benzo condensed pyridines: quinolines and isoquinolines alkaloid natural products largets class of...
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BENZO CONDENSED PYRIDINES:
QUINOLINES AND ISOQUINOLINES
N
QuinolineBenzo[b]pyridine(1-azanaphtalene)
abc
1
2
34
4a
56
78
8a
N
IsoquinolineBenzo[c]pyridine(2-azanaphtalene)
abc
12
34
4a
56
78
8a
Alkaloid Natural Products
•Largets class of secondary metabolites, >6500 compds known•Contains N, most compds basic (alkaline), often heterocyclic•Often highly toxic•Found in certain higher plants (seldom in bacteria)•Little is known regarding why alkaloids are produced•Biosynthesis from amino acids
Quinoline alkaloidsCinchona pubescens (Kinatre) from South America
N
R
HO NH
R=OMe: Quinine (Cinchonidine epimer at C-9)
R=H: Quinidine (Cinchonine epimer at C-9)
Quinidine: AntiarytmicQuinine: Antimalaria
N CF3CF3
HONH
Mefloquine
N Cl
HNN
Chloroquine
Dihydroquini(di)ne and der.Chiral ligandsAsym. dihydroxylation (Sharpless)
Isoquinoline alkaloids
Curare - Pilgift - Søramerikanske indianereBland. Av flere alkaloider med muskeslammende effektFlere plantekilder bl.a. Chondodendron tomentosum
MeON
Me
MeO
MeONH
Me
MeO
MeO
MeO
MeO
MeO
MeO
OMe
O
OO
O
MeO
O
HO
OOH
OMe
NR
Me
NMe
Me
R=H: TubocurarinR=Me: Wrong struct.
N N
Ex. Mivacurium kloridMuscle relax, anesthesia
Cl
NO
ON
O
O
Cl
Esterase
Cl
NOH
HON
O
O
Cl
HOOH
Succinsyrekolin
Suksametonium, Curacit® “Nesset”
Isoquinoline alkaloids
Morfinanalogs, binds to opiopeptide (endorfin / enkefalin) reseptors
O OHO
NCH3
O OHHO
NCH3
H3CO OO
NCH3
H3C CH3
Thebaine Morfin
NH
OHHO OH
OH
Norlaudanosoline
NH
OH
OH
HO
HON
O
O
O
O
O O O
N
O
O
O
O
Papaverine(against spasms)
NH2
HO
CO2H
Tyr
Noskapin(not analgetic,not adiction)
OOHHO
N
Morfin
O
OHN
OH
H2N
OH
HN
HN
OO
O
NH
HO
NH
O
O
S
Met-enkefalin
Tyr N-terminalin opiopeptides
N NN
pKa 5.2 pKa 4.9 pKa 5.5
Protonation Electrophilic Ar. Subst.
N
E
N
N
E
N
Major isomers shownE
E
Halogenation in the Pyridine Ring
N
HClBr2
NH
Br
N
H BrH
Br Br
N
H Br
H BrH
- H
N
Br
HH Br
- HBr
N
Br
N
HClBr2
N
Br
Nucleophilic Addition - Nucleophilic Ar. Subst.
N
Nu
N Nu
N
Nu
N
Nu
N
Nu
N
Nu
N
XN X N
X
X=halogen
Reactivity towards Nu as N NX
X
Nu-radicals (Minisci react.)attacks in the same pos.
ANRORC (Add. Of Nu., Ring Opening and Ring Closure)
NH
NH
N
NH2
N
Br NaNH2N
Br
H NH2
N
Br
HNH2
NNH2
H
NuN N
Nu
X N NuX+ X
a) X=Hb) X=Good leaving group
Oxy- and Aminoderivatives - Tautomeri
-All - isomers amino (not imino)
-“One”-Isomers:
NH
O NH
O
NH
O
Tautomeric Mixt.:
N
OH
NH
OQuinoid struct.: NegativeAmide: Possitive
Synthesis - Quinolines
NH2
O
O
H
-2 H2O NNH2
OH
- H2O [ox]
NH
Synthesis - Isoquinolines
NH2
O
O
HH
N-2 H2O
O NH2
OEtEtO
H
- H2O- 2 EtOH
N
NH2
O
X R
X: -Cl, H
- H2O [ox]
N