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Applications Solution Phase Synthesis Scavengers for Nucleophiles 32 Scavengers for Electrophiles 34 Metal Scavengers 36 Phosphine Mediated Chemistry 38 Bases and Neutralizing Reagents 42 Coupling Reagents 44 Reducing Reagents 48 Oxidizing Reagents 52

Solid Phase Extraction Acid Removal 54 Catch and Release 56 Mixed Bed Ion Exchange 57 SPE Metal Removal 58

Solid Phase Sythesis Solid Phase Organic Synthesis 62 Synthesis of Carboxylic Acids 63 Synthesis of Amides 64 Synthesis of Amides and Sulfonamides 65 Synthesis of Amines and Alcohols 66 Synthesis of Other Functional Groups 67

Peptide Synthesis Peptide Synthesis 68 Peptide Synthesis - Fmoc Chemistry 69 Peptide Synthesis - Boc Chemistry 70 Peptide Purification 71

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Scavengers for NucleophilesSolution Phase Synthesis

IntroductionOne of the most commonly employed nucleophiles in organic synthesis is the amine. The five products described in this section are all effective for amine scavenging, while some are also suitable for the removal of species such as thiols, alcohols and hydrazines.

PL-AAEM and PL-CHO: Selective Primary Amine ScavengersIn most scavenging applications, the differentiation between product and starting material has to be well defined. While the removal of an amine in the presence of an amide is simple, the removal of a primary amine in the presence of other amine functionalities may cause difficulties.

Typical Experimental: Synthesis of a Secondary Amine via Reductive AminationPrimary amine (1.2 eq) and carbonyl (1 eq) were added to a solution of 3:1 THF/AcOH. After 15 minutes PL-BH3(CN) (2.5 eq) was added and the reaction was agitated at room temperature for 16-24h. PL-CHO or PL-AAEM (0.5 eq) was then added in order to scavenge the excess amine. After two hours the reaction was filtered. The resin was washed with more THF (3x5mL), and the combined organics were reduced in-vacuo to yield the secondary amines as acetate salts.

PL-MIA and NCO: Broad Spectrum Scavengers of AminesIn other examples of amine removal, selectivity of reagent and product is not so critical. PL-NCO and PL-MIA are highly effective broad spectrum scavengers of amines. They will scavenge both primary and secondary amines and are the scavengers of choice in amide bond forming reactions.

PL-AAEM and PL-CHO are selective to the scavenging of primary amines only, allowing the end user to remove excess primary amine in the presence of more substituted amine products. These scavengers are therefore perfectly suited to reductive amination and some multicomponent reaction applications.

PL-NCO and PL-MIA resins can also be used to scavenge other nucleophilic species such as hydrazides and thiols.

Handling ConsiderationsPL-NCO is a reactive material and will decompose in the presence of moisture. We recommend that the material be refrigerated under a protective atmosphere of argon or nitrogen. When the material is ready to be used it should be allowed to warm up fully to room temperature. The reactivity of PL-NCO means that handling the material in bulk scale may be difficult. In process applications we therefore recommend the use of PL-MIA.

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Scavengers for NucleophilesSolution Phase Synthesis

PL-SO2Cl: A Polymer Supported Tosyl Chloride EquivalentAlthough PL-MIA and PL-NCO can be used to sequester non-amine functionality, such as thiols, alcohols and hydrazines, a more robust method is to employ a supported tosyl chloride equivalent. PL-SO2Cl is a broad spectrum scavenger of nucleophiles ranging from anilines to alcohols.

Handling ConsiderationsPL-SO2Cl is a highly reactive, moisture sensitive material. The material should be refrigerated under an inert atmosphere and be allowed to warm fully to room temperature prior to use. End users should also be aware that for every mole of nucleophile that is sequestered, an equimolar amount of HCl is formed.

Scavengers for NucleophilesSpecies to be Scavenged Structure Reaction Conditions

PL-AAEM Resin (Acetoacetoxyethyl Ketoester) 1% DVB

Selective to 1° aminesEnolates

RNH2

RCOCH=COR12-3 eq PL-AAEM relative to nucleophile 3-18h, 20°C

PL-CHO Resin (Aldehyde) 1% DVB, MP

Selective to 1° aminesEnolates

RNH2

RCOCH=COR12-3 eq PL-CHO relative to nucleophile, AcOH (trace) 4-18h, 50°C

PL-MIA Resin (Methylisatoic Anhydride) 1% DVB

1° and 2° AminesHydrazinesThiolsThiolates

RNH2, RR1NH2

RNHNH2

RSHRS-

2-3 eq PL-MIA relative to nucleophile 3-18h, 20°C

PL-NCO Resin (Isocyanate) 1% DVB, MP

1° and 2° AminesHydrazinesThiolsThiolatesAlcohols

RNH2, RR1NH2

RNHNH2

RSHRS-

ROH

2-3 eq PL-NCO relative to nucleophile 1-16h, 20°C

PL-SO2Cl Resin (Sulfonyl Chloride) 1% DVB

Aromatic aminesAlcoholsAlkoxides

ArNH2

ROHRO-

2-3 eq PL-SO2Cl relative to nucleophile 1-16h, 20°C

For PL-AAEM see page 75For PL-CHO see page 86

For PL-MIA see page 116For PL-NCO see page 120

For PL-SO2Cl see page 136

Ordering Information

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Scavengers for ElectrophilesSolution Phase Synthesis

IntroductionThe high throughput processing and purification of reaction products may be assisted by the use of polymer supported scavengers for the removal of electrophiles from solution. This section will describe some key applications for the removal of common electrophilic reagents.

PL-DETA and PL-EDA: Multi-Purpose Amine Based ScavengersFor most synthetically useful electrophilic reagents, an amine group is a very simple and effective scavenging group. We offer two amine containing scavenger reagents on a high load base material. PL-EDA is an ethylenediamine functionalized material, while PL-DETA is the diethylenetriamine derivative.

In the scheme above, the effective scavenging of acid halides is shown. PL-DETA and PL-EDA are also highly effective in scavenging isocyanates, isothiocyanates and sulfonyl chlorides.

PL-SO2NHNH2: An Effective Scavenger of Carbonyl SpeciesAldehydes and ketones are commonly used intermediates in a range of useful chemistries, such as reductive amination and a host of multicomponent reactions. This polymer supported sulfonyl hydrazide equivalent is the most effective way of removing excess carbonyl reagents from a reaction. Although PL-SO2NHNH2 is effective at neutral pH, the addition of trace AcOH to the reaction during scavenging can increase its scavenging rate.

Experimental: Reductive AminationAmine (1 eq) and carbonyl (1.2 eq) were added to a solution of 3:1 THF/AcOH. After 15 minutes PL-BH3(CN) (2.5 eq) was added and the reaction was agitated at room temperature for 16-24h. After this time PL-SO2NHNH2 (2 eq) was added in order to scavenge the excess aldehyde. After two hours the reaction was then filtered. The resin was washed with more THF and the combined organics were reduced in-vacuo to yield the amine product as an acetate salt.

The reduction in scavenging time for a solution of benzaldehyde when PL-SO2NHNH2 was used in the presence of trace AcOH.

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Scavengers for ElectrophilesSolution Phase Synthesis

For PL-DETA see page 94For PL-EDA see page 99

For PL-SO2NHNH2 see page 137For PL-DEAM see page 93


PL-DEAM: Scavenger for Boronic AcidsBoronic acids are highly useful building blocks in modern synthetic chemistry. Perhaps their most well known use is in the palladium catalyzed Suzuki-Miyaura cross-coupling reaction. Boronic acids can also be used in Petasis (boronic Mannich) multicomponent reactions.

Once a particular boronic acid has been scavenged from solution, it can be later released using acidic conditions. This can be advantageous if the boronic acid is of high value or in limited quantity.

Experimental: Release of Boronic AcidsAt the end of the scavenging process, the reaction product will be contained in the combined organic washings. Place the filtered resin into a small vial or flask and add a mixture of THF/AcOH/TFA (90:5:5). The recommended resin to solvent ratio should be 1g of resin per 15mL of solvent. Leave the mixture for 1-2 h. Filter the resin and wash with THF. Evaporate the combined solvents to isolate the boronic acid.

Amine Based Scavengers Species to be Scavenged Structure Reaction Conditions

PL-DETA Resin (Diethylenetriamine) 1% DVB, MP

Acid chloridesSulfonyl chloridesIsocyanatesIsothiocyanates

RCOClRSO2ClRNCORNCS

3-6 eq PL-DETA relative to electrophile 4h, 20°C

PL-EDA Resin (Ethylenediamine) 1% DVB, MP

Acid chloridesSulfonyl chloridesIsocyanatesIsothiocyanates

RCOClRSO2ClRNCORNCS

3-6 eq PL-EDA relative to electrophile 4h, 20°C

Scavenger for CarbonylsSpecies to be Scavenged Structure Reaction Conditions

PL-SO2NHNH2 Resin (Sulfonyl Hydrazide) 1% DVB

AldehydesKetones

RCHORC=OR1

2 eq PL-SO2NHNH2 relative to carbonyl, AcOH (trace) 1-3h, 20°C

Scavenger for Boronic AcidsSpecies to be Scavenged Structure Reaction Conditions

PL-DEAM Resin (Diethanolamine) 1% DVB, MP

Boronic acids R-B(OH)2 2-3 eq PL-DEAM relative to boronic acid 4h, 20°C


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Metal ScavengingSolution Phase Synthesis

IntroductionThe range of reliable organometallic reactions has increased greatly over the last few decades, and it is common to see such reactions in a high throughput chemistry environment. The removal of subsequent metal residues from organic reactions and samples is therefore essential to provide clean, screenable compounds for synthetic organic and medicinal chemistry. This section will describe a range of polymers designed specifically for metal sequestration.

Macroporous TechnologyThe StratoSpheres range of metal scavengers is based on a specially engineered macroporous polymer. Macroporous polymers are non-swelling, rigid and highly porous particles, perfectly suited for metal removal applications. Macroporous particles work in a broad range of solvents including polar and non-polar, protic and non-protic.

Recommended Products for Metal Removal

PL-

BnS

H M

P

PL-

DE

AM

MP

PL-

DE

TA M

P

PL-

ED

A M

P

PL-

TBD

MP

PL-

Thio

urea

MP

PL-

TMT

MP

PL-

Ure

a M

P

Metal SolutionCadmium l

Cobalt u

Copper u l u

Iron u l

Lead u u

Mercury 4 u

Nickel (0) and (II) l

Palladium (0) and (II) 4 l u l 4 l

Platinum l l 4 l l 4 4

Ruthenium l l l l 4

Tin l l l l 4 4 4

Zinc l

Recommended Product 4 Scavengers l Reported in Literature u

Composition of macroporous particle


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Metal ScavengingSolution Phase Synthesis

For PL-BnSH see page 81For PL-DEAM see page 93For PL-DETA see page 94

For PL-EDA see page 99 For PL-TBD see page 139For PL-Thiourea see page 142

For PL-TMT see page 143 For PL-Urea see page 142


Amine Based Scavengers Metal to be Scavenged Structure Applications

PL-BnSH Resin (Mercaptomethyl) MP

Copper, Iron, Palladium, Platinum, Ruthenium, Tin • Pd coupling reactions• Hydrogenation• Olefin metathesis

PL-DEAM Resin (Diethanolamine) MP

Platinum, Tin • Sn (II) reduction• Radical chemistry• Stille coupling• Pt hydrogenation

PL-DETA Resin (Diethylenetriamine) MP

Cobalt, Palladium, Platinum, Ruthenium, Tin • Sn (II) reduction• Radical chemistry• Stille coupling• Ru, Pt hydrogenation

PL-EDA Resin (Ethylenediamine) MP

Cadmium, Lead, Nickel, Palladium, Platinum, Ruthenium, Tin • Sn (II) reduction• Radical chemistry• Stille coupling• Ru, Pt hydrogenation

PL-TBD Resin (1,5,7-Triazabicyclo[4.4.0]dec-5-ene) MP

Mercury, Palladium, Platinum, Tin • Pd coupling reactions• Sn mediated chemistry• Mercuric oxidation

PL-Thiourea Resin (N-Ethyl Thiourea) MP

Palladium, Platinum, Ruthenium, Tin • Sn (II) reduction• Radical chemistry• Stille coupling• Ru, Pt hydrogenation

PL-TMT Resin (Trimercaptotriazine) MP

Copper, Palladium • Cu “CLICK” chemistry• Pd coupling reactions• Hydrogenation

PL-Urea Resin (N-Butyl Urea) MP

Palladium, Tin • Pt hydrogenation• Sn mediated chemistry


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Phosphine Mediated ChemistrySolution Phase Synthesis

IntroductionThe favored oxidation of P(III) reagents to P(V) species is the basis of most organophosphorous chemical reactions. Of the many reagents available, triphenylphosphine (TPP) is perhaps the most well known. In TPP applications the reagent is converted to a P(V) oxide. This species can create serious purification difficulties. Triphenylphosphine oxide (TPPO) is difficult to precipitate in the presence of other organic compounds and will often co-elute with compounds of interest during flash or HPLC purification. These purification issues have led to the development of polymer supported triphenylphosphine derivatives, where the phosphine oxide remains on the polymer support and can be simply filtered out of the reaction.

Problems with Conventional Methods of ManufactureThe standard way of producing polymer supported triphenylphosphine derivatives is to use lithiation chemistry. The two choices for a base polymer are either a non-functionalized styrene-divinylbenzene polymer or a brominated polystyrene. After treatment with butyl lithium (BuLi) the lithiated polystyrenes are reacted with chlorodiphenylphosphine to produce the polymer supported triphenylphosphine.

This manufacturing process creates a range of issues. The harsh nature of lithiation chemistry means that the base polymer integrity is compromised, inorganic salt contamination and extra crosslinking is observed. Another disadvantage of using the lithiation chemistry, is that batch size and batch reproducibility are also severely affected. This results in the handling of BuLi in large quantities needing extreme care. In addition, the handling of the chlorodiphenylphosphine reagent is difficult due to its extreme air sensitivity, which means that a percentage of the reagent is already oxidized to the P(V) form prior to its attachment to the polymer. The P(V) component can play no part in the desired chemical reaction. As a result, most commercially available lithiation based materials have an actual P(III) loading significantly below the quoted phosphorous loading.

The Varian Polymer Laboratories Approach: CopolymerizationUsing a proprietary suspension copolymerization technique, PL-TPP is manufactured using the styryldiphenylphosphine monomer. This means that the P(III) species is introduced in the polymerization step, without the need for any harsh chemical modification. The end result is a very clean product, free of chemical contamination and P(V) species. This unique manufacturing method allows us to produce this material in multi kg quantities with excellent batch to batch reproducibility.

High purity PL-TPP (white) in between two materials formed by lithiation chemistries.

(PL-TPP)

Feature Benefit

n Lithiation free manufacture n Ultra clean polymer free of salts and P(V) species

n Copolymer technology n Quoted phosphine content reflects P(III) loading directly

n Scalability and excellent batch reproducibility

n Zero fines and leachables


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Ether Formation: Mitsunobu ReactionThe Mitsunobu reaction allows the coupling of two alcohol species to form an ether. This dehydration/coupling reaction requires a phosphine reagent and an azodicarboxylate species such as DEAD or DIAD. The P(V) oxide formed at the end of the reaction creates the main purification challenge in this reaction.

The use of an immobilized TPP is well suited to this reaction and is fast becoming the accepted way of conducting such an application. The insoluble P(V) polymer is filtered away at the end of a reaction and the ether product can then be isolated and purified using standard methods.

The formation of the phosphonium salt intermediate is achieved through the simple treatment of PL-TPP with an alkyl halide (preferably Br or I). This intermediate is stable and can be stored as a building block for later use. In order to effect olefination, the salt is treated with the strong base sodium hexamethyldisilazide (NaHMDS). The resultant ylide then undergoes [2+2] cyclization, then elimination to produce the alkene and the immobilized phosphine oxide, which is simply removed by filtration.

Synthesis of Alkenes: The Wittig ReactionThe Wittig reaction is the coupling of a phosphonium ylide with an aldehyde to give an alkene and triphenylphosphine oxide.

Typical Experimental: Mitsunobu ReactionPL-TPP (2 eq) was added to a solution of phenol (1 eq) and alcohol (1 eq) in DCM. The reaction was then cooled to 0oC over a period of five minutes. A solution of DIAD (1.2 eq) was then added dropwise and the reaction was left to agitate for 12-24 h. The reaction was diluted two-fold with DCM and washed with 0.1M KOH solution and 0.1M HCl solution. The combined organics were then dried (MgSO4) and concentrated under vacuum to yield the ether product.

Phenol Alcohol Yield

91%

89%

75%

Typical Experimental: Wittig ReactionHeat alkyl bromide (5 eq) in THF to 60°C and then add the PL-TPP (1 eq). Leave reaction to agitate for 12-24 h. Wash the resin with THF then DCM and then dry under vacuum for 24 hours. Resuspend the resin in THF under argon and add five equivalents of NaHMDS (as a 1M solution in THF) and agitate the resin for 1 hour. Wash the resin with THF. Add the carbonyl compound (0.5 eq) and agitate under argon for 24-48 h. After filtration and concentration of the solution, the olefin can be isolated free of any associated phosphine oxide by-products.

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HalogenationThe conversion of alcohols and carboxylic acids is a fundamental reaction in organic synthesis. There are several methods which use TPP as a reagent. Allowing the reaction to proceed under mild conditions makes this an attractive alternative to using hygroscopic and reactive reagents which are difficult to handle.

There are two methods that we recommend for this application. The first is a halosaccharin-mediated halogenation of alcohols, which proceeds at neutral pH. The second is the more classical carbon tetrachloride (CCl4) or carbon tetrabromide (CBr4) halogenation. For most examples, we recommend that the alkyl or acyl halides be then used in-situ without further isolation or purification.

Experimental 1: Halosaccharin MethodAdd PL-TPP (2 eq) to a solution of N-Halosaccharin (2 eq) and alcohol (1 eq) in DCM. Agitate the reaction at room temperature for four hours. At the end of the reaction filter the resin and wash with DCM (3x5mL). The alkyl halide can then be used in-situ or purified using a short silica column.

Note: Some alkyl halides may be too reactive to undergo further purification.

Experimental 2: Halogenated Solvent MethodAdd PL-TPP (1 eq) to a solution of alkyl alcohol or acid (0.5 eq) in CCl4 (if a bromination is required use CBr4 in a solution of DCM). Heat the reaction to 80oC for 2-3 h. At the end of the reaction, filter the resin and wash with DCM (3x5mL). The alkyl or acyl halide can then be used in-situ or concentrated under vacuum and resuspended in a different solvent prior to use in the next stage of a reaction.

Use as a Metal Ligand / Metal ScavengerTriarylphosphines are commonly used as transition metal ligands for a range of catalysts. During a catalytic process, phosphine ligands can dissociate from the metal center and experience oxidation to a P(V) species. The use of a polymeric phosphine will therefore be advantageous in such cases.

PL-TPP can be used to immobilize a range of metal species, palladium and ruthenium, in particular. This property also makes it suitable as metal scavenger in some instances.

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For PL-TPP resin see page 144 For PL-TPPO resin see page 145



PL-TPPO: An Effective Dehydration ReagentP(V) reagents can also be used in synthetic transformations. PL-TPPO (triphenylphosphine oxide) can easily be converted to a polymer supported triphenylphosphine ditriflate species upon treatment with triflic anhydride. This species can then be used as a dehydrating reagent in a variety of organic transformations such as amide and ester bond formation and aza-Mitsunobu chemistry.

ExperimentalAdd PL-TPPO (2 eq) to anhydrous DCM and allow to condition for five minutes. To this suspension carefully add trifluoromethanesulfonic anhydride (1 eq) and allow the mixture to agitate for 15 minutes. Reduce the reaction temperature to 0oC and add the sulfonic acid pyridine salt (1 eq) over a period of five minutes. Add triethylamine (2 eq) and amine 1.2 eq and allow to warm up in temperature over 30 minutes. Filter away the resin and dilute the filtrates with a two-fold volume of DCM. Wash the reaction mixture with 2M HCl solution and saturated sodium bicarbonate solution. Dry the organic component with MgSO4, filter, and concentrate the combined organics under vacuum to yield the sulfonamide product.

Scavenger for CarbonylsStarting Materials Product Structure Reaction Conditions

PL-TPP Resin (Triphenylphosphine) 1% DVB, MP

ROHRCO2HR-OH + R-OHR-X + R1-Y

HalogenationCarbon Carbon bond formationAlcohol activationAcyl halide formation

RXRCO2ClR-O-RR-R1

Halogenations:1 eq PL-TPP, 0.5 eq of acid or alcohol in CX4, (X = Cl,Br) 2h, 80°C.

Pd coupling reactions:2 eq of PL-TPP used as phosphine ligand.

Mitsunobu:Pd coupling reactions 2 eq ofPL-TPP used as phosphine ligand.

Scavenger for CarbonylsStarting Materials Product Structure Reaction Conditions

PL-TPPO Resin (Triphenylphosphine Oxide) 1% DVB

PL-TPPO + (CF3SO2)2O

→[Activated species]

+ R1SO3H + R2NH2

R1SO2NHR2 1 eq PL-TPPO 0.75 eq (CF3SO2)2O in DCM0.25h, 0°C

Then 1 eq RSO3H (salt) and 1.2 eq RNH2 in DCM 0.5h, 0°C

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Bases and Neutralizing ReagentsSolution Phase Synthesis

IntroductionThe use of an immobilized base can offer significant purification advantages over solution phase equivalents. At the end of a reaction the immobilized bases can be simply filtered away. In some cases this can remove the need for a liquid-liquid extraction based work-up, which is highly advantageous if the reaction product is present in a small quantity or is partially soluble in water.

Reagent Selection: ApplicationsQuaternary based reagents (PL-CO3, PL-HCO3, PL-OH)Quaternary ammonium based materials have excellent ion exchange properties and therefore are very good at scavenging a range of acidic reagents and substrates from organic reactions. Favourable reaction kinetics allow for acid sequestration to occur in a short timeframe, reducing the possibility of side reactions.

Strong bases (PL-DIPAM, PL-TBD, PL-TEA)These reagents are basic enough to promote deprotonation and are therefore useful in alkylation protocols. PL-TBD has a pKa (conjugate acid) of around 14 and will deprotonate most phenolic compounds with ease. PL-TEA and PL-DIPAM can be used as direct replacements for triethylamine and Hunig’s base, respectively.

Cyclic amine based reagents (PL-MPH, PL-MPPZ, PL-PIP, PL-PPZ)These polymer supported bases are all suitable for the removal of acid species of the form H-X. The reagents have similar pKa values, functionality and efficacy. The range of choice here allows the end-user the flexibility to match an immobilized reagent to the equivalent chemical reagent for a particular solution phase procedure.

Neutralizing Reagents – Quaternary Amine SupportedSynthetic Utility Structure Reaction Conditions

PL-CO3 Resin (Carbonate) MP, MR

A polymer supported carbonate equivalent, which can be used in a broad range of acid scavenging and neutralization applications.

3.5 eq PL-CO3

0.5-2h, 20°C

PL-HCO3 Resin (Hydrogen Carbonate) MP, MR

A polymer supported hydrogen carbonate equivalent, which can be used in a range of acid scavenging applications. In particular the removal of TFA, AcOH and formic acid.

3.5 eq PL-HCO3

0.5-2h, 20°C

PL-OH Resin (Hydroxide) MP

A polymer supported hydroxide equivalent, which can be used to quench organic reactions. This product can also be used as a precursor to other quaternary ammonium based reagents.

3.5 eq PL-OH0.5-2h, 20°C

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Bases and Neutralizing ReagentsSolution Phase Synthesis

For PL CO3 see page 91For PL-HCO3 see page 103For PL-OH see page 121For PL-DIPAM see page 96

For PL-TBD see page 139For PL-TEA see page 140For PL-MPH see page 117

For PL-MPPZ see page 118For PL-PIP see page 126For PL-PPZ see page 127


Strong BasesSynthetic Utility Structure Reaction Conditions

PL-DIPAM Resin (Diisopropylethylamine) 1% DVB, MP

A polymer supported equivalent of diisopropylethylamine (Hunig’s base), which can be used in a range of synthetic applications.

pKa (conjugate acid) PL-DIPAM ~ 11

2-3 eq PL-DIPAM relative to limiting reagent

PL-TBD Resin (1,5,7,-Triazabicyclo[4.4.0]dec-5-ene) 1% DVB, MP

A strong base suitable for use in the alkylation of phenols, amines and activated methylene compounds.

pKa (conjugate acid) PL-TBD ~ 14

2-3 eq PL-TBD relative to limiting reagent

PL-TEA Resin (Triethylamine) 1% DVB

A polymer supported equivalent of triethylamine. Useful in a broad spectrum of chemistries, such as the scavenging of acids of the form H-X.

pKa (conjugate acid) PL-TEA ~ 11

2-3 eq PL-TEA relative to limiting reagent

Scavengers for AcidsSynthetic Utility Structure Reaction Conditions

PL-MPH Resin (Morpholine) 1% DVB, MP

A polymer supported morpholine equivalent, which is used in the scavenging of acids H-X.

2-3 eq PL-MPH relative to acid

PL-MPPZ Resin (N-Methyl Piperazine) 1% DVB

A polymer supported N-methyl piperazine equivalent, which is used in the scavenging of acids H-X.

2-3 eq PL-MPPZ relative to acid

PL-PIP Resin (Piperidine) 1% DVB, MP

A polymer supported piperadine equivalent, which is used in the scavenging of acids H-X.

2-3 eq PL-PIP relative to acid

PL-PPZ Resin (Piperazine) 1% DVB, MP

A polymer supported piperazine equivalent, which is used in the scavenging of acids H-X. It can also be used as a catalyst for Knoevenagel reactions.

2-3 eq PL-PPZ relative to limiting reagent


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Coupling ReagentsSolution Phase Synthesis

IntroductionThe amide bond is a key structural component made up of a large number of small molecules and is a core component of peptide and protein chemistry. The standard method for making an amide bond is to employ a reagent which can activate a carboxylic acid allowing for nucleophilic attack of an amine. In this section, the key role that immobilized coupling reagents can play and the advantages they offer is described.

Typical Experimental: Synthesis of a Secondary Amine via Reductive AminationTo a carboxylic acid (1.5 eq) and HOBt (0.5 eq) in anhydrous DCM or DMF, add PL-DCC or PL-EDC resin (2 eq). Agitate the mixture under an inert atmosphere for 15 minutes at room temperature. After this time add amine (1 eq) and agitate for a further 12-16 h. Once the amidation reaction is complete, remove excess amine using PL-NCO or PL-MIA (0.5 eq). Filter the solution, washing with DCM (3x5mL). Concentrate the combined organic washings under vacuum to afford amide products.

If HOBt is used in the coupling reaction, it can be removed using PL-HCO3 MP or a PL-HCO3 MP SPE device.

PL-DCC and PL-EDC: Carbodiimide Mediated AmidationPL-DCC and PL-EDC are polymer-bound carbodiimides for producing activated acid species, particularly in the formation of amide bonds. Typically solution phase carbodiimide reagents introduce purifications due to the formation of insoluble urea by-products. When using a supported reagent, the insoluble urea by-product remains bound to the resin and therefore greatly simplifies the work-up procedure.

This method can also be applied for the synthesis of sulfonate esters if the amine is substituted with an alcohol (0.5 eq).

Typical Experimental: Synthesis of a SulfonamideTo a solution of a sulfonyl chloride (3 eq) in anhydrous DCM add PL-DMAP (1 eq). Agitate the mixture under an inert atmosphere for 1 hour. Filter and wash the resin thoroughly with DCM to remove any unreacted sulfonyl chloride. Resuspend the activated PL-DMAP resin in DCM and amine (0.5 eq). Agitate the reaction for a further 16-24 h. Remove the PL-DMAP resin by filtration and wash with DCM (3x5mL). Combine the organic solutions and concentrate under vacuum to afford the sulfonamide product.

PL-DMAP: An Effective Transfer CatalystPL-DMAP is a nucleophilic catalyst used as a transfer reagent in acylation and sulfonylation reactions. It can also be used as a base in standard organic transformations as a scavenger for acids H-X. A very powerful application of this resin is in the synthesis of sulfonamides.

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PL-HOBt and PL-TFP: Activated Ester Reagents for AmidationHOBt is perhaps the most well known active ester reagent and is used routinely in a range of small molecule and peptide synthesis applications. It can, however, be difficult to remove from solution at the end of a reaction. PL-HOBt can be used as a direct replacement for the solution phase reagent, and can be simply filtered away at the end of the reaction. PL-HOBt can also be used to make intermediate active esters, which can be used in-situ or isolated and used later. One particularly useful application is the transfer of oxy-carbonyl based protecting groups.

As a similar product in this application field, PL-TFP enables the preparation of the solid supported equivalent of Pfp esters. Pfp esters are a well-established means of activating carboxylic acid and sulfonic acid derivatives. PL-TFP can be used either as a solid support in a reaction, allowing isolation of intermediates or it can be used solely as a reagent in a one-step protocol. Carboxylic acids may be loaded onto PL-TFP using a conventional carbodiimide coupling. The preferred reagent for this step is diisopropylcarbodiimide (DIC). The urea by-product formed by this reagent is soluble in DCM, allowing it to be washed out of the polymer effectively.

Step 2: Amide Formation StepThe preformed PL-TFP or PL-HOBt active ester (1.5 eq) was added to a solution of amine (1 eq) and tertiary base (Et3N or iPr2NEt, 1 eq) in THF. The mixture was left to agitate for 4-6 h, after which the resin was filtered and washed with DCM and THF. The combined organic solutions were concentrated under vacuum to afford the amide product.

Experimental: Formation of AmidesStep 1: Active Ester FormationPL-TFP or PL-HOBt (1.5 eq) was added to a solution of carboxylic acid (1 eq) and DMAP (0.6 eq) in DCM/DMF. After 10 minutes, DIC (4 eq) was added and the mixture left to agitate for two hours. After this time, the resin was filtered and washed with DMF, DCM and THF. The activated ester intermediates were then dried and stored under anhydrous conditions, awaiting the next stage.

Handling and Storage of Active Ester IntermediatesIf dried, stored under argon and refrigerated, the PL-TFP and PL-HOBt intermediate active esters can be isolated and stored for later use if desired. Care should be taken to allow no moisture into the storage device. In our experience isolated active esters can be used successfully after a period of 1-2 months.


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PL-Mukaiyama and PL-IIDQ: Highly Reactive Coupling ReagentsPL-Mukaiyama is a highly versatile reagent, capable of a range of coupling reactions. It can also be used in the dehydration of ureas and the desulfurization of thioureas, giving access to carbodiimide and guanidine functionalities.

PL-IIDQ is a polymer supported equivalent of the classical solution phase coupling reagent and provides in-situ activation of carboxylic acids. PL-IIDQ creates a mixed anhydride which then reacts with the amine forming an amide bond. The only by-products created are carbon dioxide and isobutanol. The intermediate formed during the PL-IIDQ coupling is sufficiently stable to allow prolonged reaction times with particularly unreactive amines, such as anilines or secondary amines.

PL-IIDQ ExperimentalPL-IIDQ (2 eq) was added to acetonitrile and allowed to condition for five minutes. Carboxylic acid (1 eq) and amine (1 eq) were then added to the reaction. The mixture was left to agitate for 24 h. At the end of the reaction the resin was filtered and washed with DCM and MeOH (3x5mL). The combined organic solutions were then concentrated under vacuum to afford the amide product.

Acid Amine Yield

87%

98%

94%

PL-Mukaiyama ExperimentalPL-Mukaiyama (2 eq) was added to DCM and allowed to condition for five minutes. Carboxylic acid (1.05 eq), amine (1 eq) and Et3N (3 eq) were then added and the reaction was left to agitate for 2-6 h. Once the reaction had reached completion, the resin was filtered and washed with DCM and MeOH (3x5mL). The combined organic solutions were then concentrated under vacuum to afford the amide product.

Acid Amine Yield

97%

86%

93%


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Coupling Reagents: Carbodiimide BasedStarting Materials Product Structure Reaction Conditions

PL-DCC Resin (Cyclohexyl Carbodiimide) 1% DVB

RCO2H + R1NH2 RCONHR1 2 eq PL-DCC1.5 eq acid1 eq amine in DCM12-16h, 20°C

PL-EDC Resin (1-Ethyl-3-(3-Dimethylaminopropyl)-Carbodiimide) 1% DVB, MP

RCO2H + R1NH2 RCONHR1 2 eq PL-EDC1.5 eq acid1 eq amine in DCM12-16h, 20°C

For PL-DCC see page 92For PL-EDC see page 100For PL-HOBt see page 106

For PL-TFP see page 141For PL-Mukaiyama see page 119For PL-IIDQ see page 109

For DMAP see page 98


Coupling Reagents: Acyl Transfer ReagentStarting Materials Product Structure Reaction Conditions

PL-DMAP Resin (4-Methylaminopyridine) 1% DVB, MP

RCO2H + R1NH2 RCONHR1 1.5 eq PL-DMAP3 eq (RCO)2O or RSO2ClWash with DCM 0.5 eq R1OH or R1NH2

16-24h, 20°C


Coupling Reagents: Activated EstersStarting Materials Product Structure Reaction Conditions

PL-HOBt Resin (1-Hydroxybenzotriazole) 1% DVB

RCO2H + R1NH2 RCONHR1 1.5 eq PL-HOBt1 eq acid4.5 eq DIC0.6 eq DMAP in 4:1DCM/DMF2h, 20°C

PL-TFP Resin (Tetrafluorophenol) 1% DVB, MP

RCO2H + R1NH2 RCONHR1 1.5 eq PL-TFP1 eq acid4.5 eq DIC0.6 eq DMAP in 4:1DCM/DMF2h, 20°C

Coupling Reagents: Non-Carbodiimide BasedStarting Materials Products Structure Reaction Conditions

PL-Mukaiyama Resin (N-Methyl-2-Chloropyridinium Triflate) 1% DVB

RCO2H + R1NH2

RCO2H + R1OHRNH(C=S)NHR1

RCONHR1

RCO2R1

RHN=C=NHR1

2 eq PL-Mukaiyama1.05 eq acid1 eq amine3 eq Et3N in DCM2-6h, 25°C

PL-IIDQ Resin (2-Isobutoxy-1-Isobutoxycarbonyl-1,2-Dihydroquinoline) 1% DVB

RCO2H + R1NH2 RCONHR1 2 eq PL-IIDQ1 eq acid1 eq amine in CH3CN24h, 20°C


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Reducing ReagentsSolution Phase Synthesis

IntroductionPolymer supported reagents offer key advantages to solution phase equivalents in that the end purification is simplified. Boron by-products remain bound to the resin and can be removed with simple filtration. Many solution phase reagents rely on aqueous based quench or work-up, which may compromise compound integrity and yield.

Effect of Resin Quality on Unwanted Side ReactionsThis product is manufactured via an ion exchange of sodium borohydride onto the quaternary amine base resin. We employ proprietary washing steps to ensure that any excess residual sodium borohydride is removed from the macroporous polymer.

Quaternary ammonium borohydride species will reduce an α-β unsaturated ketone selectively on the carbonyl group. However, sodium borohydride will also remove the double bond in a 1,4 reduction. The experimental study below was designed to indicate the level of residual sodium borohydride, if any, present in the PL-BH4, and two polymer supported borohydride products from alternative suppliers. The ratios of the desired alcohol and the over reduced product was determined by GC analysis. PL-BH4 showed a very low level of the over reduced cyclohexanol product, indicating the lowest level of residual sodium borohydride.

Reagent

PL-BH4 95% <1%

Source A 87% 7%

Source B 94% 4%

Experimental: Reduction of CarbonylsA mixture of PL-BH4 (2 eq), aldehyde (1 eq) in MeOH was agitated at room temperature for 2-12 h. Once the reaction was shown to be complete by GC analysis the resin was filtered and washed with MeOH (2x5mL). The combined organic solutions were evaporated under vacuum to afford the desired alcohol product.

Product Yield Purity

97% >99%

99% 98%

96% >99%

PL-BH4: An Effective Immobilized BorohydridePL-BH4 is the polymer supported equivalent of sodium borohydride.


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PL-BH3(CN): A Reagent for Reductive AminationReductive amination allows the synthesis of structurally diverse amines using readily available starting substrates under mild conditions. Immobilized reagents and scavengers are particularly useful in reductive amination methodologies as they can help eliminate post reaction purification issues. PL-BH3(CN) is easy to handle and is more stable than its solution phase equivalent. The resin is simply filtered away at the end of the reaction, removing residual boron species in the process.

The Synthesis of Secondary AminesPL-BH3(CN) is effective in the synthesis of secondary amines. Acetic acid is needed in the reaction to aid imine formation, and will also help activate the cyanoborohydride species. At the end of the reaction any excess primary amine can be scavenged in the presence of the secondary amine product using the selective PL-AAEM resin. Excess aldehyde is scavenged using PL-SO2NHNH2, which has an increased scavenging rate when under acidic conditions.

The Synthesis of Tertiary AminesThe method for tertiary amine synthesis is very similar to the secondary amine synthesis. The reaction times may be slightly longer and extra equivalents of starting materials are recommended. Excess aldehyde is removed in the same way as before, while PL-NCO or PL-MIA can be employed to scavenge excess secondary amine.

Experimental: Secondary Amine SynthesisWith Limiting CarbonylPrimary amine (1.2 eq) and aldehyde (1 eq) were added to a solution of 3:1 THF/AcOH. After 15 minutes PL-BH3(CN) (2.5 eq) was added and the reaction was agitated at room temperature for 16-24 h. After this time PL-AAEM (0.5 eq) was added in order to scavenge the excess amine. After two hours the reaction was then filtered. The resin was washed with more THF and the combined organics were concentrated under vacuum to yield the secondary amines as acetate salts.

With Limiting AminePrimary amine (1 eq) and aldehyde (1.5 eq) were added to a solution of 3:1 THF/AcOH. The same reaction conditions were followed as above. When the reaction was complete, PL-SO2NHNH2 (1 eq) was added in order to scavenge the excess carbonyl. After one hour the reaction was then filtered. The resin was washed with more THF and the combined organics were concentrated under vacuum to yield the secondary amines as acetate salts.

Experimental: Tertiary Amine SynthesisWith Limiting CarbonylSecondary amine (1.5 eq) and aldehyde (1 eq) were added to a solution of 3:1 THF/AcOH. After 15 minutes PL-BH3(CN) (2.5 eq) was added and the reaction was agitated at room temperature for 16-24 h. After this time PL-NCO or PL-MIA (0.5 eq) was added in order to scavenge the excess amine. After two hours the reaction was worked-up as previously described.

With Limiting AmineSecondary amine (1 eq) and aldehyde (1.5 eq) were added to a solution of 3:1 THF/AcOH. The same reaction conditions were followed as above. When the reaction was complete, PL-SO2NHNH2 (2 eq) was added in order to scavenge the excess carbonyl. After two hours the reaction was then filtered, washed with THF and isolated as before.


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SPE Mediated Clean-up of Reductive Amination ReactionsReductive amination is a chemical transformation that is highly amenable to high throughput synthesis and chemical automation. The reaction conditions are relatively mild and the starting materials are available in large diverse arrays from commercial sources.

One potential problem in high throughput methods is the end product isolation and purification. Most reductive amination methods yield the amine product as an acetate salt. The neutralization and/or purification of these species can be time consuming and may involve aqueous extractions and chromatography steps. The two methods below are specific SPE techniques, which can be used to purify and freebase products from reductive amination reactions.

Catch and Release Purification of Reductive Amination ProductsThe catch and release purification of amines using an SCX type sorbent is a well-adopted technique. The ability to remove interferences and then selectively elute an amine product is very advantageous. PL-SO3H MP SPE is a high capacity ultra pure polymer SCX variant designed for this very type of application. The acetate is exchanged onto the sorbent and impurities are washed away. The amine is then released using a methanolic ammonia solution.

Acid Removal and Freebasing of Reductive Amination ProductsAn alternative to the catch and release method is to employ a PL-HCO3 MP SPE to scavenge excess acetic acid in a flow through method. As the sample passes through the tube, any free acetic acid will be removed and amine acetate salts will be freebased at the same time. This method reduces the amount of handling steps needed compared to catch and release methods, eliminating the ammonia elution step.

Experimental: SPE Mediated Amine Clean-upIt is recommended that the amine salt is isolated from the reaction via evaporation under vacuum. The salt should then be resuspended in a suitable solvent prior to loading.

Catch and Release Methodn Precondition the PL-SO3H MP SPE device with 1mL

of MeOH.

n Apply the amine salt in a suitable solvent and allow to pass under gravity.

n Wash the SPE device with with 2-5mL of MeOH or THF to remove non-retained impurities.

n Elute the compound of interest using 2M ammonia in methanol solution.

Acid Removal and Freebasing Methodn Precondition the PL-HCO3 MP SPE device with 1mL

of MeOH.

n Load the organic salt in a suitable solvent and allow to pass under gravity through the device.

n Once the solution has passed through wash the tube with 1-2mL of MeOH.

n Isolate the freebase compound by evaporating the collected eluents under vacuum.

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For PL-BH3(CN) see page 78For PL-BH4 see page 79For PL-AAEM see page 75

For PL-NCO see page 120For PL-SO2NHNH2 see page 137For PL-HCO3 MP SPE see page 160

For PL-SO3H MP SPE see page 160For PL-MIA see page 116



Reducing Reagents Starting Materials Products Structure Reaction Conditions

PL-BH3(CN) Resin (Cyanoborohydride) MP, MR

RCHO

RCHO + R1NH2

RCH2OH

RCH2NHR1

2.5 eq PL-BH3(CN)1 eq carbonyl1.2 eq amine3:1 THF/AcOH12-16h, 20°C

PL-BH4 Resin (Borohydride) MP, MR

RCHO

RCOR1

RCH2OH

RCH(OH)R1

2 eq PL-BH4

1 eq carbonyl in EtOH/MeOH2-12h, 20°C

Scavengers for Reductive Amination Species to be Scavenged Structure Reaction Conditions

PL-AAEM Resin (Acetoacetoxyethyl Ketoester) 1% DVB

Selective to 1° amines

Enolates

RNH2

RCOCH=COR1

2-3 eq PL-AAEM relative to nucleophile 3-18h, 20°C

PL-MIA Resin (Methylisatoic Anhydride) 1% DVB

1° and 2° AminesHydrazinesThiolsThiolates

RNH2, RR1NH2

RNHNH2

RSHRS-

2-3 eq PL-MIA relative to nucleophile 3-18h, 20°C

PL-NCO Resin (Isocyanate) 1% DVB, MP

1° and 2° AminesHydrazinesThiolsThiolatesAlcohols

RNH2, RR1NH2

RNHNH2

RSHRS-

ROH

2-3 eq PL-NCO relative to nucleophile 1-16h, 20°C

PL-SO2NHNH2 Resin (Sulfonyl Hydrazide) 1% DVB

Aldehydes

Ketones

RCHO

RC=OR1

2 eq PL-SO2NHNH2 relative to carbonyl, AcOH (trace)1-3h, 20°C

SPE Devices Synthetic Utility Structure Reaction Conditions

PL-HCO3 MP SPE MP

Used for the removal of residual AcOH, or for the freebasing of amine acetate salts during reductive amination reactions.

Use SPE device in a 2 molar excess.

PL-SO3H MP SPE MPUsed for the catch and release purification of amines. Use SPE device in a 2 molar

excess.


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Oxidizing ReagentsSolution Phase Synthesis

IntroductionPolymer supported oxidants offer a key advantage to solution phase equivalents, in that the end purification is simplified. Oxidant by-products remain bound to the resin and can be removed by simple filtration. Many solution phase oxidants rely on aqueous based quench or work-up, which may compromise compound integrity and yield.

ExperimentalPL-IO4 (2 eq) was added to a solution of 1,2-diol or sulfide in DCM or THF. The reaction was agitated for 2-12 h, depending on the reactivity of the substrate (sulfide oxidation typically takes longer). Once the reaction had reached completion, the polymer supported reagent was removed by filtration and washed with the reaction solvent (DCM or THF, 3x5mL). The product was then isolated via evaporation of the combined filtrates.

Starting Material Product Yield

93%

98%

100%

PL-RuO4: Catalytic Oxidation of Alcohols to CarbonylsPL-RuO4 is a catalytic oxidant used in the oxidation of primary alcohols to aldehydes. The catalytic ruthenium species is regenerated using air as a co-oxidant. PL-RuO4 can also be used for converting hydroxylamines into nitrones, a chemical group that is useful in heterocycle formation. At the end of a reaction any ruthenium residues remain ionically bound to the polymer particle.

ExperimentalPL-RuO4 (0.2-0.5 eq) was added to a solution of primary alcohol in toluene or THF under aerobic conditions. The reaction was agitated for 24-48 h at 80°C. Once the reaction was complete, the polymer supported reagent was removed by filtration and washed with THF (3x5mL). The products were then isolated via evaporation of the combined organic solutions.

Note: In these examples air was used as a co-oxidant for the catalyst. In some examples reaction rates can be improved when N-methylmorpholine N-oxide (2 eq) is employed.


94% 99%

91% >99%

96% 95%

PL-IO4: Cleavage of 1,2 diols and Selective Oxidation of SulfidesPL-IO4 is a very useful, highly selective oxidant, which operates under mild conditions. The most commonly used application for periodate based species is the cleavage of 1,2 diols. PL-IO4 will also oxidize sulfides to sulfoxides without the formation of any sulfone products. This type of selectivity can be very difficult with other oxidants.


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Oxidizing ReagentsSolution Phase Synthesis

PL-IBX AmideHypervalent iodine based oxidants have attracted much attention due to their excellent selectivity and mild reaction conditions. Examples of such solution phase oxidants are Dess-Martin periodinane and IBX. These reagents can have solubility issues in some organic solvents.

By immobilizing the iodine species to a solid support, this problem is by-passed. PL-IBX Amide is very simple to use, with no co-oxidants or other reaction additives required.

ExperimentalPL-IBX Amide (2 eq) was added to a solution of alcohol in DCM or THF. The reaction was agitated at room temperature for 6-12 h. Upon reaction completion, the polymer supported reagent was removed by filtration and washed with DCM (3x5mL). The product was then isolated via evaporation of the combined filtrates.

NB: For activated species such as benzylic alcohols, reaction times are fast, in some cases under one hour. Less activated species such as alkyl alcohols have a much longer reaction time (6-12h).


96% >99%

95% >99%

99% >99%

Oxidizing Reagents – Hypervalent IodineStarting Materials Products Structure Reaction Conditions

PL-IBX Amide (Hypervalent Iodine Oxidant) 1% DVB

R1CH2OHR1CH(OH)R2

R1CHOR1COR2

2 eq PL-IBX Amide relative to alcohol 6-12h, 20°C

Oxidizing Reagents – Quaternary Amine FunctionalityStarting Materials Products Structure Reaction Conditions

PL-IO4 Resin (Periodate) MP

R1CH(OH)CH(OH)R2

R1SR2R1CHO + R2CHOR1(S=O)R2

2 eq PL-IO4 relative to 1,2 diol or sulfide 2-12h, 20°C

PL-RuO4 Resin (Perruthenate) MP

R1CH2OHR1CH(OH)R2

R1CHOR1COR2

0.2-0.5 eq PL-RuO4 relative to alcohol. Use air as co-oxidant 24-48h, 80°C.

For PL-IO4 see page 111 For PL-RuO4 see page 133 For PL-IBX Amide see page 108



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Acid RemovalSolid Phase Extraction

BackgroundThere are a host of chemical reactions where the end product is usually isolated as a salt form. Often a compound will need to be in a neutral form prior to the next synthetic step or screening/storage. PL-HCO3 MP SPE is a simple flow through device which removes acidic counter ions from organic compounds with ease. This straightforward step can often be used as an alternative to an aqueous based work-up or purification of a compound.

Description: Polymer supported hydrogen carbonateApplication: Scavenger of Organic and Inorganic Acids (AcOH, HCO2H, TFA, HCl)See Also: PL-SO3H MP SPE, PL-MIXED MP SPE

Application 1: Freebasing of Basic Polar Compounds Present as AcOH, TFA and HCl SaltsAcetic acid is a commonly used acid that helps promote reactions such as reductive amination. AcOH is also a by-product of acetylation reactions where its anhydride is employed. TFA is a very useful organic acid, employed in a range of chemistries from Boc deprotection, acid catalysis and the cleavage of compounds from a solid support. HCl is one of the most commonly used acids in synthesis and will form organic salts readily.

PL-HCO3 MP SPE can be used with a broad range of solvent conditions. The end user has the flexibility to pass a reaction mixture directly through the device, or take an existing organic salt, resolvate it in an appropriate solvent and freebase it. The counter ion on the SPE sorbent is “traceless”, converting to water and CO2 upon treatment with acid.

Application 2: The Removal of Acidic Mobile Phase Additives from HPLC FractionsThe use of organic acids in HPLC mobile phase to aid solubility of polar molecules is a well known technique. Typically, 0.1% TFA in mixtures of water and acetonitrile are most commonly employed. If a compound is purified using preparative HPLC, the resulting solvent fractions will contain traces of TFA. If these species then undergo evaporation or lyophilization the resulting organic species may be present as a TFA salt. The long-term stability of acid salts, particularly TFA ones, may be compromised.

TFA Removal GuidelinesFor all acid removal applications we recommend that the SPE device be used as a two fold excess. The nominal loadings of the available devices are shown below, along with the theoretical volume of 0.1% TFA which can be quenched when used as a two fold excess.

Sorbent Mass Nominal Loading(Per Device)

Theoretical Quantityof 0.1% TFA Quenched

100mg 0.18mmol ~ 5mL

200mg 0.36mmol ~ 10mL

500mg 0.9mmol ~ 25mL

19F NMR spectra showing TFA salt (black) and freebase compound (blue) after SPE treatment.

19F Spectra shows no TFA signal post SPE treatment.

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Acid RemovalSolid Phase Extraction

Other Applications of PL-HCO3 MP SPEThe standard strong anion exchange abilities of PL-HCO3 MP SPE also make it useful for other applications. The removal of activating reagents such as HOBt and HOSu from a reaction can be achieved by simply passing through the SPE tube. PL-HCO3 MP SPE can also be used as a scavenger of carboxylic acid reagents from coupling and some multicomponent reactions.

Experimental 1: Freebasing of TFA SaltsThis method is for the freebasing of isolated compounds that are present as salts. Salt forms suitable for this application include: AcOH, TFA, Formate, HCl and HBr.

n Precondition the PL-HCO3 MP SPE device with 1mL of MeOH. (If MeOH is incompatible then a similar low viscosity solvent can be used such as DCM or THF).

n Wash the SPE device with 2-3mL of the solvent in which the sample will be added.

n Load the organic salt in a suitable solvent and allow to pass under gravity through the device.

n Once the solution has passed through, wash the tube with 1-2mL of MeOH.

n Isolate the freebase compound by evaporating the combined organics under vacuum.

Experimental 2: Removal of Acidic Mobile Phase AdditivesThis method is for the removal of acidic mobile phase additives from HPLC eluents. The most common example would be 0.1% TFA in MeCN/H2O systems.

n Precondition the PL-HCO3 MP SPE device with 1mL of MeOH.

n Wash the SPE device with 2-3mL of the blank HPLC eluent.

n Allow the acid containing HPLC fraction to pass through the SPE device under gravity.

n Once the solution has passed through wash the tube with 1-2mL of MeOH (favored) or the blank HPLC eluent.

n Isolate the freebase compound by evaporating the combined organics under vacuum.

For PL-HCO3 MP SPE see page 160


Additional InformationVarian Polymer Laboratories also manufactures SPE devices in bulk quantities. Please contact us for a quotation.


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Description: Polymer supported sulfonic acid (SCX H+ form)Application: Scavenger of Bases, Catch and ReleaseSee Also: PL-MIXED MP SPE, PL-HCO3 MP SPE

Catch and ReleaseSolid Phase Extraction

BackgroundPL-SO3H MP SPE is an SPE device containing a high load sulfonic acid SCX polymer. This product is used in the catch and release purification of basic polar compounds.

Typical Experimentaln Precondition the PL-SO3H MP SPE device with 1mL

of MeOH. (If MeOH is incompatible then a similar low viscosity solvent can be used such as DCM or THF).


n Apply sample in a suitable solvent and allow to pass under gravity.

n Wash the SPE device with with 2-5mL of MeOH or THF to remove non-retained impurities.

n Elute the compound of interest using 2M ammonia in methanol solution.

Note: If 2M NH3 is too concentrated and causes side reactions then a dilution to 1M or 0.5M can be made. In most cases this will still allow reasonable release of compound.

Purification of Basic Amine Containing MoleculesSCX sorbent-mediated catch and release methods are very attractive for a whole range of chemical methodologies. The clean up of an amine after cleavage from a solid support or after a Boc group removal can be achieved with this simple method. The synthesis of amines, particularly via reductive amination protocols is perfectly suited to this method. The crude amine acetate salts can be purified effectively and freebased in the same step.

For PL-SO3H MP SPE see page 160



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Description: Mixed bed ion exchangeApplication: Scavenger of Bases, Catch and ReleaseSee Also: PL-SO3H MP SPE, PL-HCO3 MP SPE

BackgroundPL-MIXED MP SPE is a mixed bed polymeric sorbent containing equimolar quantities of a strong cation exchanger (H+ form) and a strong anion exchanger (OH- form). This mixed mode functionality allows for the sequestration of cationic and anionic interferences from organic solutions. This SPE device is particularly useful in the purification of non-polar, neutral molecules.

Mixed Bed Ion ExchangeSolid Phase Extraction

Effective Work-Up of Amidation ReactionsPL-MIXED MP SPE is a highly convenient single use device that has broad utility, particularly in amidation reactions. Most amide bond forming chemistries use polar or ionizable activating agents, auxiliaries and bases. The mixed mode functionalities of PL-MIXED MP allow these to be removed while the desired amide passes unhindered through the tube. This type of work-up is amenable to high throughput chemistry as it can, in some cases, eliminate the need for a liquid-liquid extraction. The whole clean-up process is performed under gravity, and the sorbent within the device is tolerant to a broad range of solvents.

For PL-MIXED MP SPE see page 160



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Metal Removal SPESolid Phase Extraction

Application: Metal RemovalSee Also: PL-BnSH, PL-DEAM, PL-DETA, PL-EDA, PL-TBD, PL-Thiourea, PL-TPP, PL-Urea, PL-SO3H

BackgroundThe removal of residual metal species from organic reactions is essential for providing clean screenable compounds. This range of SPE devices is designed to remove a broad range of metal reagents from organic reactions using a a simple gravity flow method. Unwanted residues are retained by the sorbent in the SPE tube, allowing the desired compound to pass through.

TechnologyThe StratoSpheres SPE range for metal removal is designed around a specially engineered macroporous particle, which has a high capacity and can be used in a broad range of solvents. This base polymer is functionalized with a range of ligands designed to bind metal-based reagents and catalysts. If the metal species being removed is highly colored, then the sorbent will self-indicate, allowing the end user to determine when the device is nearing capacity.

Product Metals Removed

PL-Guanidine MP SPE Au, Bi, Cd, Hg, Pd, Pt, Re, Rh, Sn, Zn

PL-Thiol MP SPE Ag, Au, Cu, Fe, Pd, Pt, Ru, Rh, Sn, Pb, Cu

PL-Thiourea MP SPE Ag, Cd, Cu,Pt, Pd, Ru, Rh, Hg, Cu, Ni

PL-Urea MP SPE Ag, Au, Hg, Ni, Pd, Pt, Re, Sc, PL-Thiol MP SPE device scavenging a 1000ppm Pd(II) solution.

Application: Removal of Palladium and Rhodium CatalystsTwo of the most common catalytic metals used in drug discovery are palladium and rhodium. Popularity of cross-coupling reactions and catalytic hydrogenation has made the removal of these two metals highly relevant. The table below is a representative study of the removal of some common Pd and Rh catalysts screened against the metal removal SPE devices.

Catalyst Start Concentration Guanidine MP SPE Thiol MP SPE Thiourea MP SPE Urea MP SPE

Pd(OAc)2 1000 ppm <0.1 ppm <0.1 ppm <0.1 ppm 2.1 ppm

PdCl2 1000 ppm <0.1 ppm 1.1 ppm 2.3 ppm >10 ppm

Pd(PPh3)4 600 ppm <0.1 ppm <0.1 ppm 0.9 ppm >10 ppm

Wilkinson’s Catalyst 300 ppm 4.8 ppm <0.1 ppm <0.1 ppm <0.1 ppm

Rh2(OAc)2 300 ppm <0.1 ppm <0.1 ppm <0.1 ppm >10 ppm

Description: Polymer supported guanidine Description: Polymer supported thiol

Description: Polymer supported thiourea Description: Polymer supported urea


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Metal Removal SPESolid Phase Extraction

Application: Removal of Ruthenium Based Metathesis ReagentsOlefin metathesis is a very powerful organic reaction. The most commonly used catalysts for this reaction are the Grubbs and Grubbs-Hoyveda ruthenium based catalysts. These are typically difficult to remove from a reaction and can cause ring opening polymerization (ROMP) if not fully removed and concentrated during reaction work-up. PL-Thiol MP SPE and PL-Thiourea MP SPE are effective in scavenging this class of reagents.

Catalyst (Start conc. of 1000ppm in DCM)

PL-Thiol MP SPE

PL-Thiourea MP SPE

A Grubbs 1st Gen. 0.8 ppm 0.1 ppm

B Grubbs 2nd Gen. 4.0 ppm 1.2 ppm

C Grubbs-Hoveyda 1st <0.1 ppm <0.1 ppm

D Grubbs-Hoveyda 2nd <0.1 ppm <0.1 ppm

Typical Experimentaln Precondition the SPE device with 1mL of MeOH.

(If MeOH is incompatible then a similar low viscosity solvent can be used such as DCM or THF).


n Load the sample in a suitable solvent and allow the solution to pass through the device under gravity (flow rate is typically ~ 0.5mL per minute).

n Wash the SPE device with 2-3mL of MeOH.

n Isolate product via the evaporation of the combined organics.

Residual metal species (red) are sequestered by the sorbent while product (green) passes through the tube.


For PL-Guanidine MP SPE see page 161For PL-Thiol MP SPE see page 161

For PL-Thiourea MP SPE see page 161For PL-Urea MP SPE see page 161

For Metal Removal Screening Kit see page 161


The simple methodology allows the end user to quickly screen a particular catalyst or reagent against the range of SPE devices.

These SPE devices can be used on vacuum or positive pressure manifolds, although excessively high flow rates may affect the performance of the metal scavenger.


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Metal Removal SPE: Special StudySolid Phase Extraction

BackgroundStratoSpheres SPE for metal removal has proven to be effective for a variety of common catalysts and metal reagents. However, the evolution of modern synthesis means that nearly all metals in the periodic table can be used as some form of reagent or catalyst. A special study was commissioned to screen our SPE metals against 64 common and rare metals.

A series of ICP standards with a starting concentration of 100ppm was passed through each tube, where the sorbent was used in a five-fold excess. The residual metal concentration was then determined using a Varian 720-ES instrument. The final concentration (ppm) is shown below the atomic symbol on the individual periodic tables.

This unique study offers the end user a ‘best guess’ starting point when considering the sequestration of a more exotic or less commonly used metal based reagent.

PL-Guanidine MP SPE

PL-Thiol MP SPE


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Metal Removal SPE: Special StudySolid Phase Extraction

Periodic Table Key

PL-Thiourea MP SPE

PL-Urea MP SPE

For more information on Varian ICP instrumentation please visit www.varianinc.com


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IntroductionIn solid phase synthesis, the polymer support acts as a temporary protecting group. Most often this means that, as the compound is released from the polymer during the cleavage reaction, the functional group used to attach the compound to the support is regenerated. For example, a carboxylic acid may be immobilized and protected as an ester, but the product when cleaved, will contain a carboxylic acid group. In a smaller number of cases it is possible to cause some form of transformation during the cleavage reaction. One of the simplest ways is to immobilize a carboxylic acid, but to cleave it as an amide. Finally there is also a class of supports which may be described as ‘traceless’. This means that the product cleaved from the polymer does not contain any characteristic functional group that can be identified at the point of attachment to the resin.

The purpose of this section is to show the commonest reactions typically performed by solid phase synthesis. It is divided into categories based on the chemical class of the product released from the resin. Each list is ordered according to the strength of acid required to cause cleavage (starting with strongest acid first and ending with those resins which may be cleaved under basic conditions). This will allow the user to choose the most appropriate product for a particular application to complement the other protection strategies that are being used.

Solid Phase Organic SynthesisSolid Phase Synthesis

An overview of the different types of products that may be obtained from polymer supports is given in the table below:

Product Car

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Am

ides

Sul

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Am

ines

Alc

oh

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Oth

ers

NotesAlkenyl Substituted ResinsPL-DHP 4 Equivalent to THP protecting groupPL-REM 4 Tertiary amine synthesisPL-Wang-Acr 4 Tertiary amine synthesisAmine Substituted ResinsPL-AMS Attachment of linkersPL-BZA Traceless linker via triazinePL-IDC 4 Primary amine synthesisPL-MBHA 4

PL-Ramage 4

PL-Rink 4 (4) (4) Also hydroxamatesPL-Rink MBHA 4

PL-Sieber 4 4 Also nitrile synthesisFormyl Substituted ResinsPL-FMP 4 4 4 GuanidinesPL-FMPB 4 4

PL-FDMP 4 4

PL-FDMPB 4 4

PL-IND 4 4 4 Ureas, thioureas and guanidinesPL-ICHO 4 4 4 Ureas, thioureas and guanidinesHalogen Substituted ResinsPL-Bromoacetal 4 Cyclative cleavagePL Cl-Trt-Cl 4 4 4 4 Thiols and imidazolesPL-CMS 4 (4) EstersPL-PBSPL-Wang-Br 4 4

Hydroxyl Substituted ResinsPL-HMBA 4 4

PL-HMS 4

PL-HTP 4 4

PL-IPG 4 Aldehydes and ketonesPL-IPG-Diol 4 Aldehydes and ketonesPL-Carboni 4 Aldehydes and ketonesPL-Carboni-Diol 4 Aldehydes and ketonesPL-MAMP-OH 4

PL-Wang 4 (4) Also phenolsSafety Catch Substituted ResinsPL-SABu 4 4 4 Also esters, thioesters and hydrazidesPL-SABz 4 4 4 Also esters, thioesters and hydrazidesOther ResinsPL-BIG-W 4 Unnatural amino acids and peptidomimeticsPL-BnSH Heterocycles via unsaturated ketonesPL-Oxime 4 4 Also esters, thioacids, hydrazides and hydroxamatesPL-Wang-TCA 4 4

PL-Weinreb 4 Aldehydes and ketones


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Synthesis of Carboxylic AcidsStarting Materials Product Structure Cleavage Conditions

PL-CMS & PL-HMS Resins 1% DVB

R1-COOH R2-COOH HF or TFMSA

PL-Wang & PL-Wang-Br Resins 1% DVB

R1-COOH R2-COOH 95% TFA in DCM

PL-Wang-TCA Resin 1% DVB

R1-COOH R2-COOH 95% TFA in DCM

PL Cl-Trt-Cl Resin 1% DVB

R1-COOH R2-COOH 5% TFA in DCM orAcOH/DCM/TFE

PL-SABu Resin 1% DVB

R1-COOH R2-COOH BrCH2CN then KOH (aq) in THF

PL-SABz Resin 1% DVB

R1-COOH R2-COOH BrCH2CN then KOH (aq) in THF

PL-HMBA Resin 1% DVB

R1-COOH R2-COOH NaOH (aq) in THF

Synthesis of Carboxylic AcidsSolid Phase Synthesis

For PL Cl-Trt-Cl see page 87For PL-CMS see pages 88-90For PL-HMBA see page 104

For PL-HMS see page 105For PL-SABu see page 134For PL-SABz see page 134

For PL-Wang see pages 146-147For PL-Wang-Br see page 149For PL-Wang-TCA see page 150



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Synthesis of Primary AmidesStarting Materials Product Structure Cleavage Conditions

PL-MBHA Resin 1% DVB

R1-COOH R2-COOH HF or TFMSA

PL-Rink MBHA Resin 1% DVB

R1-COOH R2-COOH 75-95% TFA in DCM

PL-Rink Resin 1% DVB


PL-Ramage Resin 1% DVB


PL-Sieber Resin 1% DVB



R1-COOH R2-COOH 1-2M NH3 in MeOH solution

PL-Oxime Resin 1% DVB

R1-COOH R2-COOH NaOH / Dioxane

For PL-HMBA see page 104For PL-MBHA see page 115For PL-Oxime see page 122

For PL-Ramage see page 129For PL-Rink see page 131

For PL-Rink MBHA see page 132For PL-Sieber see page 135

Synthesis of AmidesSolid Phase Synthesis



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Synthesis of Amides & SulfonamidesSolid Phase Synthesis

Synthesis of Secondary AmidesStarting Materials Product Structure Cleavage Conditions

PL-HMBA & PL-Oxime Resins 1% DVB

R1-COOH R2-CONH-R3 10 eq R3-NH2 in pyridine

PL-HTP Resin 1% DVB

R1-COOH R2-CONH-R3

or R2-CONR3R410 eq R3-NH2 in pyridineor 10 eq R3R4NH in pyridine

PL-SABu & PL-SABz Resins 1% DVB

R1-COOH R2-CONH-R3

or R2-CONR3R4BrCH2CNthen R3-NH2 or R3R4NH

Synthesis of Secondary Amides or SulfonamidesStarting Materials Product Structure Cleavage Conditions

PL-MAMP Resin 1% DVB

R1-NH2 R2-NHCO-R3

or R2-NHSO2-R3

25% TFA

(Note: resin requires activation before loading)

PL-FMP & PL-FMPB Resins 1% DVB

R1-NH2 R2-NHCO-R3

or R2-NHSO2-R3

10-20% TFA in DCM

PL-FDMP & PL-FDMPB Resins 1% DVB

R1-NH2 R2-NHCO-R3

or R2-NHSO2-R3

5-10% TFA in DCM

PL-IND & PL-ICHO Resins 1% DVB

R1-NH2 R2-NHCO-R3

or R2-NHSO2-R3

2-5% TFA in DCM

For PL-FDMP and PL-FDMPB see page 101For PL-FMP and PL-FMPB see page 102For PL-HMBA see page 104

For PL-HTP see page 107For PL-IND and PL-ICHO see page 110For PL-MAMP-OH see page 114

For PL-Oxime see page 122For PL-SABu see page 134For PL-SABz see page 134



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For PL Cl-Trt-Cl see page 87For PL-CMS see pages 88-90For PL-REM see page 130

For PL-Rink see page 131For PL-Wang see pages 146-147For PL-Wang-Acr see page 148

For PL-Wang-Br see page 149For PL-Wang-TCA see page 150

Synthesis of Amines & AlcoholsSolid Phase Synthesis

Synthesis of AminesStarting Materials Product Structure Cleavage Conditions

PL-Rink Resin 1% DVB

R1-CHO R2-NH2 50-95% TFA in DCM

PL-REM & PL-Wang-Acr Resins 1% DVB

R1R2NH R1R2R3N Base mediated

Synthesis of AlcoholsStarting Materials Product Structure Cleavage Conditions

PL-DHP Resin 1% DVB

R1-OH R2-OH 95% TFA / 5% H2Oor PPTS / BuOH / DCM

PL-Wang & PL-Wang-Br Resins 1% DVB

Ar-OH Ar’-OH 95% TFA in DCM

PL-Wang-TCA Resin 1% DVB

Ar-OH Ar’-OH 95% TFA in DCM

PL Cl-Trt-Cl Resin 1% DVB

R1-OH R2-OH 5% TFA in DCMor AcOH/DCM/TFE

PL-CMS & PL-Wang Resins 1% DVB

R1-COOH R2-CH2OH LiBH4 or DIBAL-H



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Synthesis of Other Functional GroupsSolid Phase Synthesis

For PL-BIG-W see page 80For PL-HMBA see page 104For PL-IND and PL-ICHO see page 110

For PL-Oxime see page 122For PL-SABu see page 134For PL-SABz see page 134

For PL-Sieber see page 135For PL-Weinreb see page 151


Synthesis of Other Functional GroupsStarting Materials Product Structure Cleavage Conditions

PL-Weinreb Resin 1% DVB

R1-COOH R2-CHOor R2-CO-R3

LiAlH4 or R3MgX (X = Cl, Br or I)


R1-COOH R2-COOCH3

or R2-CONHNH2

Methanolic cleavageor Hydrazinolysis

PL-Oxime Resin 1% DVB

R1-COOH R2-COOCH3

or R2-CONHNH2

Methanolic cleavageor Hydrazinolysis

PL-SABu & PL-SABz Resins 1% DVB

R1-COOH R2-CO-OR3

or R2-CO-SR3BrCH2CNthen R3-OH or R3-SH

PL-Sieber Resin 1% DVB

R1-COOH R2-CN 10 eq TFAA5 eq pyridine

PL-IND & PL-ICHO Resins 1% DVB

R1-NH2 R1-NH(C=O)NH-R2

orR1-NH(C=S)NH-R2

orR1-NH(C=NR3)NH-R2

Urea: R2-NCO then5% TFA in DCMThiourea: R2-NCO then5% TFA in DCMGuanidine:R2-NH(C=S)NH-R3 then10% TFA in DCM

PL-BIG-W Resin 1% DVB

R1-X H2N-CHR1-COOH(unnatural amino acids)

95% TFA in DCM


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Peptide SynthesisPeptide Synthesis

BackgroundThe use of polymer supports for solid phase synthesis originated in the field of peptide synthesis. Since 1963, technology has developed to accommodate new protecting groups, new coupling chemistries and new synthesis supports. Today, solid phase peptide synthesis is recognized as a viable approach to the manufacture of peptide drugs and APIs, alongside recombinant or solution phase approaches.

Why should you choose to produce a peptide using solid phase techniques instead of using recombinant or solution phase approaches? By using solid phase synthesis you will almost certainly accelerate the manufacturing process, particularly in the early stages of drug development. The time to market is critical and the solid phase approach is much quicker to establish. Solid phase also means that unnatural amino acids and amino acid-like compounds can be utilized during synthesis. It is also possible to combine solid phase with solution phase approaches – for example it may be appropriate to produce a peptide as two or more separate fragments to be coupled in solution afterwards, or to conduct a solution phase modification of a peptide.

There are many ways to approach the synthesis of peptides using a polymer support. However, there are three fundamental questions to consider:

n Acid labile (Boc) or base labile (Fmoc) strategy?

n Manufacture of protected peptides, or concomitant protecting group removal?

n Manufacture of peptide acids or amides (or other end groups)?

The answers to these three questions will help to determine the type of synthesis support you will need.

The tert-butyloxycarbonyl (Boc) protecting group is acid labile. The resin you will require for use with Boc chemistry must therefore be stable to repeated exposure to TFA. Although the Boc amino acid route may be more economical, the actual method of final cleavage of the peptide from the support requires careful consideration as it may involve harsh acid treatment with HF, for example.

Base labile Fmoc (9-fluorenylmethyloxycarbonyl) protection is now more commonly used. An orthogonal protection strategy is possible (where the cleavage of the side chain protecting groups and cleavage from the resin are both achieved under relatively mild acidic conditions).

There are also supports available which will allow the peptide to be cleaved from the support with the side chain protecting groups remaining intact. This is particularly useful if the fragments are to be purified prior to being assembled – a process which can greatly simplify the final overall purification of the peptide product.

Finally, the functionality of the C-terminal residue of the peptide should be considered. Most frequently the peptide will terminate as a C-terminal acid or amide and therefore different resins exist to generate the appropriate functionality. However, occasionally it is necessary to cleave as an ester, alkylamide, alcohol or even aldehyde, and on some occasions it is desirable to provide a cyclic product.

Once the choice of appropriate resin has been made, the initial amino acid can be attached. In order to simplify this process, Varian Polymer Laboratories offers a wide range of resins with the initial amino acid already attached. The twenty most common amino acids in both Fmoc and Boc protected forms are available attached to PL-CMS, PL-MBHA, PL-Rink and PL-Wang resins. These items are listed in the Products section of this catalog (pages 152-159). As part of our custom manufacturing service, we are able to provide quotations for bulk quantities of amino acid loaded resins including alternative particle size and loading combinations. Our range of high quality StratoSpheres resins are therefore available ready for use and provide you with guaranteed reproducibility time after time. If you require a resin loaded with a particular amino acid which does not appear in our catalog, please contact us - we aim to provide customer satisfaction, economic service and the highest quality product.

References(1) Lloyd-Williams, P.; Albericio, F.; Giralt, E. Tetrahedron 1993, 49, 11065-11133.


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Resins for Fmoc Chemistry – Synthesis of AcidsProduct Notes Structure Cleavage Conditions

PL-Wang Resin (4-Hydroxymethylphenoxymethyl Polystyrene) 1% DVB

Peptide-COOH Fmoc amino acid is esterified to the resin using DIC with HOBt and DMAP

95% TFA in DCM

PL Cl-Trt-Cl Resin (2-Chlorotrityl Chloride) 1% DVB

Peptide-COOH Peptide cleaved under very mild acid conditions to generate peptides with protecting groups still attached

5% TFA in DCMor AcOH/DCM/TFE

Resins for Fmoc Chemistry – Synthesis of AmidesProduct Notes Structure Cleavage Conditions

PL-Rink Resin (Fmoc Rink Amide AMS) 1% DVB

Peptide-CONH2 Fmoc protecting group is removed prior to coupling of the initial amino acid

20-50% TFA in DCM

PL-Rink MBHA Resin (Fmoc Rink Amide MBHA) 1% DVB

Peptide-CONH2 Fmoc protecting group is removed prior to coupling of the initial amino acid

20-50% TFA in DCM

PL-Ramage Resin (Tricyclic Amide Linker) 1% DVB

Peptide-CONH2 A hyper acid-labile linker for the generation of protected peptide amides

2-3% TFA in DCM

PL-Sieber Resin (Fmoc Xanthydrylamine) 1% DVB

Peptide-CONH2 A hyper acid-labile linker for the generation of protected peptide amides

1-2% TFA in DCM

For PL Cl-Trt-Cl see page 87For PL-CMS see pages 88-90For PL-Ramage see page 129

For PL-Rink see page 131For PL-Rink MBHA see page 132

For PL-Sieber see page 135For PL-Wang see pages 146-147


Peptide Synthesis - Fmoc ChemistryPeptide Synthesis

Resins for Boc Chemistry – Synthesis of AcidsProduct Notes Structure Cleavage Conditions

PL-CMS Resin (Chloromethylstyrene or Merrifield) 1% DVB

Peptide-COOH Traditional support for peptides using Boc chemistry

HF or TFMSA


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Peptide Synthesis - Boc ChemistryPeptide Synthesis

For PL-AMS see pages 76-77For PL-DMA see page 97For PL-HMBA see page 104

For PL-MBHA see page 115For PL-Oxime see page 122

For PL-PEGA see pages 124-125For PL-Weinreb see page 151

Polyamide Base ResinsProduct Notes Structure Cleavage Conditions

PL-DMA Resin (Sarcosine Dimethylacrylamide) Microporous

Various Sheppard’s PepSyn™ acrylamide based resin for optimum peptide / solvent compatibility. Requires activation prior to use.

Dependent upon linker attached.

PL-PEGA Resin (Acryloylated O,O’-bis(2-Aminopropropyl)Polyethyleneglycol) Microporous

Various Meldal’s resin, a hydrophilic support allowing for permeation by enzymes for on-bead analysis.


Specialist ResinsProduct Notes Structure Cleavage Conditions

PL-AMS Resin (Aminomethylstyrene) 1% DVB

Various Ideal for attachment of various commercially available linkers


PL-HMBA Resin (4-Hydroxymethylbenzoic Acid AMS Resin) 1% DVB

Peptide-COOH / COOR / CONHR

Sheppard’s base labile resin with cleavage using nucleophiles. The benzyl ester linkage is stable to strong acid.

NaBH4 / EtOHorROH / DIPEA / DMForRNH2 / DMF

PL-Oxime Resin (p-Nitrobenzophenone Oxime Resin) 1% DVB

Peptide-COOH / COOR Allows for cleavage of peptides via hydrazinolysis with the Boc group still attached. Other nucleophiles can also be used.

NH2NH2 / DMForNaOH / DioxaneorMeOH / DMF / TEA

PL-Weinreb Resin (N-Methoxy-β-Alanine AMS Resin) 1% DVB

Peptide-CHO / COR Allows for peptides to be released as aldehydes or ketones

LiAlH4

orRMgX (X = Cl, Br or I)


Resins for Boc Chemistry – Synthesis of AmidesProduct Notes Structure Cleavage Conditions

PL-MBHA Resin (4-Methylbenzhydrylamine) 1% DVB

Peptide-CONH2 Traditional support for peptides using Boc chemistry

HF or TFMSA


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Peptide PurificationPeptide Synthesis

Peptides created using a solid phase synthesis technique will have only a limited number of undesirable components as by-products of the synthesis. However, the identification and removal of these undesirable components is a challenge to chromatographic methods. They are, by the very nature of the production method, very closely related in their structure to the desired peptide product. For this reason, high performance methods are required with the most commonly used being reversed phase HPLC. The VariTide RPC is a small particle, 6µm, material with a pore size and pore morphology which has been optimized to give high capacity for synthetic peptides of 5 amino acids to 60 amino acid residues in size. The separation of a mixture of peptide standards, oxytocin, angiotensin II, angiotensin I and insulin was used to assess the efficiency of the VariTide RPC compared with the RP-HPLC materials currently being used for the analysis and purification of synthetic peptides.

References(1) Lloyd-Williams, P.; Albericio, F.; Giralt, E. Tetrahedron 1993, 49, 11065-11133.

Historically, peptide analysis and purification has been carried out using 0.1% TFA and acetonitrile gradients. However, as the complexity of synthetic peptides increases, it may no longer be possible to obtain the desired purity and recovery due to limited solubility or co-eluting species using this eluent system. As peptides are chains of a number of amino acids, many of which can carry a charge, the net charge on the peptide will depend on the pH of the system and it will have a zero net charge at its isoelectric point, pI. Therefore, in reversed phase HPLC, by changing the pH it is possible to alter the net charge on the peptide, and on the closely related peptides, hence changing the retention and selectivity of the separation. The VariTide RPC material is designed to work across a wide pH range and so can be used with acidic, neutral and basic eluents.

The VariTide RPC column is designed as a single ‘universal’ material for purification of synthetic peptides from the µg to g level and is therefore available pre-packed in three column dimensions: 250x4.6mm, 250x10mm and 250x21.2mm ID, with scaling factors of approximately 1x, 5x and 20x. For those laboratories who prefer to work with axial compression column hardware, loose media in 100g and 1kg pack sizes is also available.


For ordering information for the VariPep range of products, please contact your local Varian office or visit the Varian, Inc. website at www.varianinc.com

Overlay Showing the Separation of the Peptide Standard Mix, Oxytocin, Angiotensin II, Angiotensin I and Insulin on the VariTide RPC Column and Five RP-HPLC Columns Routinely used for Peptide Purification

Peptides1. Oxytocin2. Angiotensin II3. Angiotensin I4. Insulin

Column: 260x4.6mm IDEluent A: 0.1% TFA in 20% ACNEluent B: 0.1% TFA in 50% ACNGradient: 0-100% B in 15 minsFlow Rate: 1mL/min

VariTide RPC

Vendor C

Vendor B

Vendor A

Synthetic Peptide Purification: VariTide™ RPC Reversed Phase HPLC

applications - amazon s3s3.amazonaws.com/.../ · applications solution phase synthesis ... solution...

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