Nucleoside analogs have acquired an important role as therapeutic agents in the field of

chemotherapy on account of their extensive biological activities. Introduction of a triazole ring into

nucleosides to improve their bioactivity for antitumor or antiviral applications has become wide spread in

drug design practices.1,2 The 1,2,3-triazole unit may be considered as a surrogate of the amide group

because these moieties have a similar H-bond acceptor capacity, a similar distance between

substituents, and a similar dipolar properties.

Scheme 1. Synthesis of mono- and disubstituted furo[2,3-d]pyrimidine

derivatives with 1,4-disubstituted 1,2,3,- triazoles.

Scheme 3. Hybrids of purines, pseudopurines and 1,2,3-triazoles.

Fig.1. a) Molecular structure of compound 3a; b) Part of the crystal structure of the

compound 3a, which shows a one-dimensional chain created two CH ••• O and one CH

••• N hydrogen bond; c) crystal packing of 3a , shown along the crystallographic axis b,

which shows the two-dimensional ribbon formed by hydrogen bonds and hydrophobic

layers between them.

a)

b)

c)

The target regioselective 1,4-disubstituted 1,2,3-triazole

derivatives were prepared by the microwave assisted Cu-

catalyzed alkyne-azide cycloaddition (CuAAC). Linear alkyl

chain, substituted aromatic moiety and cyclopropyl ring

were introduced as alkynyl substituents at C-5 and C-6 of

furo[2,3-d]pyrimidine core using modified palladium

catalyzed cross-coupling Sonogashira reaction.

Compd. X3 X7 Y R4 Yield (%) ClogPa

6 N NH - - 15 0.97

7 N N - - 50 0.97

8 N C - - 92 1.74

9 N C Br - 70 2.56

10 CH N - - 36 0.83

11 CH NH - - 67 0.83

12 N N - 64 2.68

11 N N - 36 8.68

12 N N - 26 3.44

13 N N - 34 1.68

14 N C - 61 3.84

15 N C - 74 3.44

OO OH

Compd. X3 X7 Y R4 Yield (%) ClogPa

16 N C - 49 3.44

17 N C - 41 4.20

18 N C - 55 1.68

19 N C Br 34 4.27

20 N C Br 35 5.00

21 N C Br 37 3.27

22 CH N - 80 3.29

23 CH N - 74 1.53

24 N N - 38 2.14

25 CH N - 51 2.93

26 CH N - 72 2.53

27 CH N - 80 3.29

28 CH N - 66 1.53

CF3

a Values of n-octanol/water partition coefficients logP were calculated using ChemAxon algorithm (MarvinView Ver. 6.2.2.).

N

X3 N

X7

Cl Y

propargyl bromide

K2CO3, DMF, Ar,

60 oC, 24 h

N

X3 N

N

Cl

N

X3 N

X7

Cl Y

N3R4, Cu (0), 1M CuSO4,

t-BuOH:H2O=1:1, DMF

MW, 300 W, 80OC

N3R4,Cu (0), 1M CuSO4,

t-BuOH:H2O=1:1, DMF

MW, 300 W, 80OC

X3 N

N

Cl

X3 N

X7

Cl Y

N N

N

NN

N

R4'

R4'

4, 9

5-8 10-21

22-28

Synthesis

Scheme 2. Synthesis of N-1 and N-1, N-3-subsituted

pyrimidine derivatives with 1,2,3-triazoles.

1,2,3-TRIAZOLE PHARMACOPHORE-BASED DERIVATIVES OF PURINE

BIOISOSTERES AND PYRIMIDINES

T. Gregorić1, A. Bistrović1, A. Tomljenović Paravić2, M. Sedić2, S. Kraljević Pavelić2, V. Stepanić3, T. Gazivoda-Kraljević1, S. Raić-Malić1

1Department of Organic Chemistry, Faculty of Chemical Engineering and Technology, Marulićev trg 19, 10000 Zagreb, Croatia

2Department of Biotechnology, University of Rijeka, HR-51000 Rijeka, Croatia 3Division of Molecular Medicine, Ruđer Bošković Institute, Zagreb, Croatia

Financial support from the Croatian Science

Foundation under the project No. 5596.

Compounds 4a-4d and 5a-5d were

evaluated for their cytostatic activities

against human malignant tumor cell

lines: lung carcinoma (A549),

hepatocellular carcinoma (HepG2),

pancreatic carcinoma (CFPAC-1)

cervical carcinoma (HeLa), colorectal

adenocarcinoma (SW620), pancreatic

carcinoma (MiaPaCa-2) as well as

normal mouse embryonic fibroblast

(3T3) cell lines. Compounds 4c, 5a,

5c and 5d showed marked cytostatic

activities. Cytostatic evaluations for

other synthesized compounds are

currently underway.

IC50: 50% inhibitory concentration or concentration of the compound required to inhibit tumor cell

proliferation by 50%. The cell growth rate was evaluated by performing the MTT assay.

[1] S. Raić-Malić, A. Meščić, Curr. Med. Chem. 2015, 22, 1462

[2] S. Krištafor, A. Bistrović, J. Plavec, D. Makuc, T. Martinović, S. Kraljević Pavelić, S. Raić-Malić,

Tetrahedron Lett. 2015, 56, 1222

References

Acknowledgement

12

Table 1. Antitumor activitie of compounds 4a-4d

and 5a-5d.

Introduction

Fig.3 Comparison of binding energy and binding site between known inhibitor tomudex and compounds

5a and 4c in the active site of the enzyme thymidylate synthase and their antitumor activities.

IC50 (µM)

Cell lines

Cmpd A549 Hep-G2 CFPAC-1 HeLa SW620 3T3

5c 5.33 7.11 4.53 1.64 7.86 0.59

4c 80.68 7.66 5.51 8.42 9.87 1.16

E5a= -10,02 kcal E4c= -8,39 kcal Eref= -11,19 kcal

IC50 (µM)

Cmpd. A549 Hep-G2 CFPAC-1 HeLa SW620 3T3

4a 40.93 19.14 39.54 33.28 >100 6.7

4b 64 68.93 >100 72.9 >100 50.79

4c 80.68 7.66 5.51 8.42 9.87 1.16

4d 70.27 40.75 62.74 56.36 89.58 <0.01

5a 25.49 4.47 6.87 12.58 9.82 0.07

5b 95.79 42,.73 >100 >100 >100 4.3

5c 5.33 7.11 4.53 1.64 7.86 0.59

5d 7.41 3.62 5.92 6.13 5.63 0.37

Molecular docking of compounds 4a-4d and

5a-5d in the active site of thymidilate

synthase was performed and compared with

known inhibitors. It was found that

interactions with dUMP is of great importance

for inhibitory effect of compounds. Naimly,

pyrimidine ring of synthesized compounds is

responsible for the interaction with dUMP.

F

CF3

FOO OH

OO OH

OO OH

CF3

Cl

Cl

CF3

F

FCF3

OO OH

FCF3

OO OH

F

HN

NH

O

O

I

HN

N

I

O

O

HN

N

O

O

N N

N R1

I

N

NO

N N

N R1

N

N

O

N N

N R1

O

R2

NaHDMFrt, 24 hpropargyl bromide

N3R1, Cu(0), 1M CuSO4

DMF, t-BuOH:H2O=1:1

300W, 80 oC, MW

R1=

Cl

F

R2 =

CuI

, (PPH 3

) 4Pd,

R 2

N,N

-DIP

EA, t

olue

ne

80 o C

, 24

hCl

C5H11

Br

C6H13

OR2

R2

1

2

3

a

b

c

d

e

1a-1e2a-2e3a-3e

1'a-1'e2'a-2'e3'a-3'e

HN

NH

O

O

BrN

N

O

O

BrHN

N

O

O

Br

NaH, DMFrt., 24 h

HN

N

O

O

Br

N N

N R1

N

N

O

O

Br

N N

N R2

N

N N

R2

R1, Cu (0), 1M CuSO4

DMF, t-BuOH: H2O=1:1

MW, 300W, 80 oC

N3

N3

N3

N3

F

Cl

Cl

F

Cl

R2 =

O

N3

O

N3

N3

N3

Cl

Cl

F

Cl

R1 =

R2 , DMF

CuSO4

Na-ascorbate

rt

4a-4d 5a-5d

4 5

propargyl bromide

a

b

c

d

a

b

c

dN N

N

N

Cl

N

N

N

CF3

5c

Tomudex

4c