Synthesis of Pyran, Pyridine, Thiophene, Pyrimidine and Thiazole Derivatives with Antitumor Activities

Synthesis of Pyran, Pyridine, Thiophene, Pyrimidine and Thiazole Derivatives with Antitumor Activities

Corresponding author: Dr. Rafat M. Mohareb, Department of Chemistry, Cairo University, Giza, A. R. Egypt, Email: raafat_mohareb@yahoo.com

Abstract

The aim of present study was the uses of 4- methyl cyanoacetanilide (1) in the synthesis of pyridine, pyran, thiophene, thi- azole, pyrimidine, chromen derivatives together with their antitumor evaluations. The work has resulted in the synthesis of a variety of 2- aminopyran, 2- hydroxypyran, 2-amino pyridine, 2-hydroxypyridine, 4,5,6,7-tetrahydrobenzo[b]thiophene, N-ben- zal,N-acetyl, N-phenylthiourea, thiazole, pyrimidine, phenylhydrazone, benzalydine, ethoxyethine and N- phenylmethino deriv- atives. The antitumor activities of the newly synthesized product were evaluated against cancer.

Keywords : Pyridine; Pyran; Thiophene; Pyrimidine; Antitumor Activities

Introduction

Multicomponent reactions (MCRs) have emerged as a valuable tool in the preparation of structurally diverse chemical librar- ies of heterocyclic compounds [1]. They are inherently atom economical processes in which relatively complex products can be obtained in a one-pot reaction from simple starting ma- terials, and thus they exemplify many of the desired features of an ideal synthesis. MCRs are generally much more environ- mentally friendly and offer access to large compound libraries with diverse functionalities with the avoidance of protection and deprotection steps for possible combinatorial surveying of structural variations. In view of the increasing interest in the preparation of a large variety of heterocyclic compound librar- ies, the development of new synthetically valuable MCRs with several diversity points remains a challenge for both academic and industrial institutions [2]. Thiophene and its derivatives are an important class of heterocyclic compounds possess- ing broad biological activities, such as anti-inflammatory [3], analgesic [3], antioxidant [4], antitubercular [5], antidepressant [6], sedative [6], antiamoebic [7], oral analgesic [8], an- ti-metabolite [9] and antineoplastic properties [10]. From the aforementioned reports, it seemed that the development of an efficient, rapid, and clean synthetic route towards focused libraries of such compounds is of great importance to both me- dicinal and synthetic chemists. Hence in this paper, we report a one-pot, three-component reaction for the synthesis of pyran derivatives through the reaction of α-cyano-4-methylacetani- lide (1) with cyanomethylene derivatives and aromatic alde- hydes. All the synthesized compounds were characterized us- ing FT-IR, 1H NMR, 13C NMR, and mass spectrometry and were subjected to screening towards cancer cell lines.

Results

In the present work, the multicomponent reaction of 4-meth- ylcyanoacetanilide (1) reacted with malononitrile(2) and any of benzaldehyde (3a), 4-methoxybenzaldehyde (3b), and 4-chlorobenzaldehyde (3c), in ethanolic/triethylamine gave the 2-amino pyran derivatives 4a-c, respectively. The analyt- ical and spectral data of the compounds 4a-c were the tools of their structural elucidation. Thus, the 1H NMR spectrum of compound 4a showed a singlet at δ 3.11 ppm due to the pres- ence of CH3 group, a singlet, D2O exchangeable at δ 4.82 ppm indicating the presence of NH2 group, a singlet at δ 6.05 ppm for the pyran H-4, a multiplet at δ 7.28-7.39 ppm for the two phenyl protons and a singlet, D2O exchangeable, at δ 8.29 ppm

for the NH group. Similarly, the multi-component reaction of compound (1) with ethyl cyanoacetate (5) and any of benz- aldehyde (3a), 4-methoxybenzaldehyde (3b), and 4-chloro- benzaldehyde (3c) gave the 2-hydroxypyran derivatives 6a-c, respectively (Scheme 1).

On the other hand, carrying the multi-component reactions of compound 1 with either of malononitrile (2) or ethyl cyano- acetate (5) and any of the aromatic aldehydes 3a-c but in the presence of ammonium acetate instead of triethylamine gave the pyridine derivatives 7a-f, respectively. The analytical and spectral data of compounds 7a-f were consistent with their respective structures. Thus, the 1H NMR spectrum of com- pound 7a (as an example) showed a singlet at δ 3.16 ppm due to the presence of CH3 group, a singlet, D2O exchangeable, at δ

4.89 ppm indicating the presence of NH2 group, a singlet at δ

6.14 ppm for the pyridine H-4, a multiplet at δ 7.26-7.35 ppm

for the two phenyl protons and two singlets, D2O exchangeable, at δ 8.33 & 8.38 ppm for the two NH group. The multi-com- ponent reaction of compound 1 with furfural (8) and either of malononitrile (2) or ethyl cyanoacetate (5) in ethanolic/ triethylamine gave the pyran derivatives 9a,b; respectively. Carrying the same reaction of compound 1 with either of malo- nonitrile (2) or ethyl cyanoacetate (5) but in the presence of ammonium acetate instead of triethylamine gave the pyridine derivatives 10a and 10b, respectively (Scheme 2).

Next, we moved towards the uses of compound (1) to form thiophene derivatives using the Gewald’s thiophene synthe- sis. Thus, the reaction of compound 1 with elemental sulfur

and cyclohexanone (11) in ethanolic/triethylamine gave the 4,5,6,7-tetrahydrobenzo[b]thiophene derivative 12. Com- pound 12 was used as the key starting product for the synthesis of acyclic and heterocyclic derivatives incorporated thiophene moiety. Thus, the reaction of compound 12 with any of benz- aldehyde (3a) or 4-methoxybenzaldehyde (3b) in 1,4-dioxane containing a catalytic amount of piperidine gave the N-benzal derivatives 13a and 13b, respectively. On the other hand, the reaction of compound 12 with α-chloroacetylchloride (14) in 1,4dioxane gave the N-acetyl derivative 15. The analytical and spectral data of the latter product were used to elucidate its structure. Thus, the 1H NMR spectrum of compound 15 re- vealed two multiplets at δ 1.60-1.84 and 2.22-2.40 ppm indi- cating the psesence of the four CH2 group, a singlet at δ 3.15 ppm due to the presence of CH3, a singlet at δ 5.24 ppm due to the presence of CH2 group, two doublets at δ 7.25-7.39 ppm for the phenyl protons and two singlets, D2O exchangeable, at δ 8.24, 8.30 ppm for the two NH group. Moreover, the reaction of compound 12 with phenylisothiocyanate (16) in 1,4-dioxane gave the N-phenylthiourea derivative 17 (Scheme 3).

Compounds 17 was used for further heterocyclization reac- tions to give thiazole derivatives with potential antitumor ac- tivity. Thus compound 17 reacted with acetylacetone (18) in

ethanol containing a catalytic amount of piperidine to give the pyrimidine derivative 19. The analytical and spectral data of the latter product are in agreement with its structure. Thus, the 1H NMR spectrum of compound 19 showed two multiplets at δ 1.60-1.84 and 2.20-2.38 ppm indicating the presence of four CH2 group, three singlets at δ 2.87, 3.05, 3.13 ppm due to the presence of three CH3 group, a multiplet at δ 6.22 ppm for the pyrimidine H-4, H-5, a multiplet at δ 7.28-7.36 ppm for the two phenyl protons and a singlet, D2O exchangeable, at δ

    1. ppm for the NH group. Compound 17 with its thiourea moiety capable for the synthesis of thiazole derivatives. Thus, the reaction of compound 17 with either of α-chloroacetone (20a) or ethyl chloroacetate (20b) in ethanol solution under reflux gave the thiazole derivatives 21a and 21b, respectively. Moreover, the reaction of compound 17 with ⍵-bromo-4-chlo- roacetophenone (22) in ethanol solution gave the thiazole de- rivative 23 (Scheme 4).

The 2-(2-chloroacetamido)-N-(p-tolyl)-4,5,6,7-tetrahydroben- zo[b]thiophene-3-carboxamide (15) showed interesting reac- tivity toward some chemical reagents. Thus, it reacted with

thiourea (24) in ethanol solution to give thiazole derivative

25. On the other hand, the reaction of compound 15 with ben- zenediazonium chloride in ethanolic/sodium acetate at 0-5 ºC give phenylhydrazone derivative 26, moreover, the reaction of compound 15 with salicylaldehyde (27) in ethanolic/piper- idine gave the benzylidine derivative 28.

The multi-component reaction of compound 15 with malo- nonitrile (2) and either of the aromatic aldehydes namely benzaldehyde (3a), 4-methoxybenzaldehyde (3b) or 4-chloro- benzaldehyde (3c) in ethanolic/triethylamine gave the pyran derivatives 29a-c, respectively. On the other hand, the reaction of compound 15 with malononitrile (2) and salicylaldehyde

(27) in ethanolic/triethylamine gave the 5,10b-dihydropy- rano[3,4-c]chromen-2-yl derivative (30). Formation of com- pound 30 was assumed on the intermediate formation of the expected pyran derivative followed by the Micheal addition of the 2-hydroxy group of salicylaldehyde to the 3-cyanopyrane moiety to give compound 30 (Scheme 5).

The multi-component reaction of compound 12 with triethy- lorthoformate (31) in acetic acid solution gave ethoxyethine derivative 32. Compound 32 reacted with aniline (33) in acetic acid solution to give N- phenylmethino derivative 34 (Scheme 6).

Antitumor evaluations

Fetal bovine serum (FBS) and L-glutamine, were from Gibco Invitrogen Co. (Scotland, UK). RPMI-1640 medium was from Cambrex (New Jersey, USA). Dimethyl sulfoxide (DMSO), doxo- rubicin, penicillin, streptomycin and sulforhodamine B (SRB) were from Sigma Chemical Co. (Saint Louis, USA).

Cell cultures: Three human tumor cell lines, MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer), and SF-268 (CNS cancer) were used. MCF-7 was obtained from the European Collection of Cell Cultures (ECACC, Salisbury, UK) and NCI-H460 and SF-268 were kindly provided by the Nation- al Cancer Institute (NCI, Cairo, Egypt). They grow as monolayer and routinely maintained in RPMI-1640 medium supplement- ed with 5 % heat inactivated FBS, 2 mM glutamine and antibi- otics (penicillin 100 U/mL, streptomycin 100 μg/mL), at 37°C in a humidified atmosphere containing 5 % CO2. Exponential- ly growing cells were obtained by plating 1.5 x 105 cells/mL for MCF-7 and SF-268 and 0.75 x 104 cells/mL for NCI-H460, followed by 24 h of incubation. The effect of the vehicle sol- vent (DMSO) on the growth of these cell lines was evaluated in all the experiments by exposing untreated control cells to the maximum concentration (0.5 %) of DMSO used in each assay.

Tumor Cell Growth Assay

The effects of 4a-34 on the in vitro growth of human tumor cell lines were evaluated according to the procedure adopted by the National Cancer Institute (NCI, USA) in the ‘In vitro An- ticancer Drug Discovery Screen’ that uses the protein-binding dye sulforhodamine B to assess cell growth. Briefly, exponen- tially, cells growing in 96-well plates were then exposed for 48 h to five serial concentrations of each compound, starting from a maximum concentration of 150 μM. Following this ex- posure period adherent cells were fixed, washed, and stained. The bound stain was solubilized and the absorbance was mea- sured at 492 nm in a plate reader (Bio-Tek Instruments Inc., Power wave XS, Wincoski, USA). For each test compound and

cell line, a dose–response curve was obtained and the growth inhibition of 50 % (GI50), corresponding to the concentration of the compounds that inhibited 50 % of the net cell growth, was calculated as described by the National Cancer Research Center in Cairo, Egypt. Doxorubicin was used as a positive con- trol and tested in the same manner.

Compound GI50 (mol L-1)
MCF-7 NCI-H460 SF-268
4a 0.06 ± 0.004 0.03 ± 0.003 0.1 ± 0.02
4b 0.01 ± 0.002 0.01 ± 0.004 0.04 ± 0.01
4c 0.03 ± 0.002 0.02 ± 0.003 0.05 ± 0.002
6a 0.3 ± 0.1 0.2 ± 0.08 0.5 ± 0.01
6b 0.9 ± 0.2 0.1 ± 0.02 0.3 ± 0.05
6c 2.84 ± 0.14 4.62 ± 1.04 6.08 ± 1.16
7a 28.6 ± 12.2 12.6 ± 8.6 52.4 ± 14.6
7b 26.4 ± 2.2 34.1 ± 0.8 18.8 ± 4.8
7c 18.1 ± 0.6 16.3 ± 1.4 12.3 ±1.5
7d 0.01 ± 0.003 0.02 ± 0.001 0.01 ± 0.001
7e 16.29 ± 4.06 20.81 ± 8.29 18.29 ± 6.39
7f 22.6 ± 1.4 24.9 ± 2.8 13.8 ± 3.8
9a 0.02 ± 0.005 0.06 ± 0.004 0.02 ± 0.003
9b 55.1 ± 2.7 23.2 ± 4.8 14.4 ± 2.6
10a 36.2 ± 6.24 26.19 ± 6.22 22.40 ± 3.21
10b 0.42 ± 0.2 0.14 ± 0.02 0.92 ± 0.08
12 22.6 ± 2.6 24.3 ± 0.8 30.9 ± 3.8
13a 10.8 ± 2.6 4.5 ± 0.8 4.8 ± 1.8
13b 0.73 ± 0.50 0.25 ± 0.08 1.03 ± 0.02
15 32.8 ± 0.6 36.5 ± 0.8 30.7 ± 1.6
17 70.7 ± 18.5 40.2 ± 12.8 52.4 ± 8.6
19 31.41± 2.83 20.80 ± 4.33 18.21 ±3.70
21a 0.02 ± 0.008 0.03 ± 0.006 0.05 ± 0.00
21b 22.4 ± 2.2 32.6 ± 1.4 26.8 ± 6.4
23 28.75 ± 6.16 24.58 ± 16.07 18.41 ± 4.22
25 60.6 ± 16.9 38.9 ± 10.8 50.8 ± 8.6
26 0.02± 0.005 0.01 ±0.007 0.20 ± 0.03
28 0.63± 0.07 0.80 ± 0.14 0.018 ± 0.002
29a 2.84 ± 2.04 3.62 ± 1.04 6.08 ± 2.16
29b 1.29 ± 0.04 5.29 ± 1.84 3.14 ± 1.06
29c 36.0 ± 1.8 43.0 ± 0.8 30.5 ± 1.1
30 0.31± 0.020 0.21 ±0.03 0.39 ± 0.13
32 30.6 ± 10.2 32.6 ± 8.6 24.4 ± 12.8
34 0.01 ± 0.006 0.03 ± 0.001 0.02 ± 0.004
Doxorubicin 0.04 ± 0.008 0.09 ± 0.008 0.09 ± 0.007

Table 1. Effect of the newly synthesized compounds on the growth of three human tumor cell lines.

Results are given in concentrations that were able to cause 50

% of cell growth inhibition (GI50) after a continuous exposure of 48 h and show means ± SEM of three-independent experi- ments performed in duplicate.

The effect of compounds 4a to 34 was evaluated on in vitro growth of three human tumor cell lines representing different

tumor namely (MCF-7), (NCI-H460), (SF-268) after a contin- uous exposure for 48 h, these effects were indicated through figure 1.

The results were summarized in the previous table. The results indicate that:

Compounds 4b, 4c, 7d, 9a, 21a, 34 showed the highest inhibi- tory effect against all the three tumor cell lines. Compounds 4a, 26 showed high inhibitory effect against (MCF-7), (NCI-H460). Compounds 6a, 6b, 10b, 13b, 30 showed moderate inhibito- ry effect against the three cell line. Compound 28 showed the moderate inhibitory effect against (MCF-7), (NCI-H460), and high inhibitory effect against (SF-268). (Compounds 6c, 7a, 7b, 7c, 7e, 7f, 9b, 10a, 12, 13a, 15, 17, 19, 21b, 23, 25, 29a,

29b, 29c, 32 showed the lowest inhibitory effect against the three cell lines. Comparing the inhibitory effect of the com- pound 4a, 4b, 4c it is obvious that the highest inhibitory effect of compounds 4b and 4c against all the three tumor cell lines attributed to the presence of 4-methoxy group, chlorine atom respectively which are not presence in compound 4a which showed high inhibitory effect against (MCF-7), (NCI-H46). Considering pyridine derivatives 7a-7f it is obvious that com- pound 7d with its hydroxyl and 4-methoxy groups showed highest inhibitory effect against all the three tumor cell lines. The high inhibitory effect of compound 9a relative compound 9b against all the three tumor cell lines attributed to the pres- ence of amine group moieties. Also the high inhibitory effect of compound 21a relative to 21b against all the three tumor cell lines attributed to the presence of methyl group. On the other hand the high inhibitory effect of compound 26 against (MCF- 7), (NCI-H460 ) attributed to the presence of chlorine atom and phenylhydrazone group. Finally the high inhibitory effect of compound 34 against of the three tumor cell lines attributed to the presence of N- phenylmethino group (Figure 1).

80

MCF-7

NCI-H460 SF-268

70

60

50

GI50 (µ mol/l)

40

30

20

10

0

4a 4b 4c 6a 6b 6c 7a 7b 7c 7d 7e 7f 9a 9b 10a 10b 12 13a 13b 15 17 19 21a 21b 23 25 26 28 29a 29b 29c 30 32 34

Compounds

Figure 1. GI50 of the new synthesized compounds against MCF-7,

NCI-H460 and SF-268.

Experimental General

All melting points were determined on an Electrothermal dig- ital melting point apparatus and are uncorrected. IR spectra (KBr discs) were recorded on a FTIR plus 460 or PyeUnicam SP-1000 spectrophotometer. 1H NMR spectra were recorded with Varian Gemini-200 (200 MHz) and Jeol AS 500 MHz in-

126.0, 128.9, 129.6, 130.0, 132.9, 132.6 (2 C6H4, pyran C).

Compound 4c: Yellow crystals from ethanol, yield 72 % (2.61 g), m.p> 300 °C. Anal. Calculated for C20H15ClN4O (362.81): C, 66.21; H, 4.17; N, 15.44. Found: C, 66.40; H, 4.38; N; 15.60. MS:

m/e 362 (M+, 18 %), IR, υ: 3481-3319 (NH2, NH), 3056 (CH,

aromatic), 2224, 2220 (2CN), 1634 (C=C). 1H NMR (DMSO-d6,

200 MHz): 3.12 (s, 3H, CH3), 4.89 (s, 2H, D2O exchangeable,

NH ), 6.13 (s, 1H, pyran H-4), 7.28-7.39 (m, 8H, C H , C H ),

struments spectra were performed in DMSO-d6 as solvent us- ing TMS as internal standard and chemical shifts are expressed

2

    1. (s, 1H, D2O exchangeable, NH).

6 4 6 4

as δ ppm. MS (EI) spectra were recorded with Hewlett Pack- ard 5988 A GC/MS system and GCMS-QP 1000 Ex Shimadzu instruments. Analytical data were obtained from the Micro-an- alytical Data Unit at Cairo University and were performed on Vario EL III Elemental analyzer. The Anti-tumor evaluation has been carried out through the National Cancer Research Center in Cairo, Egypt where the GI50 values were calculated.

2-Amino-4-phenyl-6-(p-tolylamino)-4H-pyran-3,5-dicarboni- trile (4a), 2-amino-4-(4-methoxyphenyl)-6-(p-tolylamino)-4H- pyran-3,5-dicarbonitrile (4b) and 2-amino-4-(4-chlorophenyl)- 6-(p-tolylamino)-4H-pyran-3,5-dicarbonitrile(4c).

General procedure: To a solution of compound 1 (1.74 g,

0.01 mol) in ethanol (50 mL) containing triethylamine (0.50 mL), malononitrile (0.66 g, 0.01 mol ) either of benzaldehyde (1.06 g, 0.01 mol), 4-methoxybenzaldehyde (1.36 g, 0.01 mol) or 4-chlorobenzaldehyde (1.41 g, 0.01 mol) was added. The reaction mixture in each case was heated under reflux for 4 h then poured onto ice/water containing few drops of hydro- chloric acid and the formed solid product was collected by fil- tration.

Compound 4a: Yellow crystals from ethanol, yield 73 % (2.4

2-Hydroxy-4-phenyl-6-(p-tolylamino)-4H-pyran-3,5-dicarbo- nitrile (6a), 2-hydroxy-4-(4-methoxyphenyl)-6-(p-tolylamino)- 4H-pyran-3,5-dicarbonitrile (6b) and 2-hydroxy-4-(4-chloro- phenyl)-6-(p-tolylamino)-4H-pyran-3,5-dicarbonitrile (6c)

General procedure: To a solution of compound 1 (1.74 g, 0.01 mol) in ethanol (50 mL) containing triethylamine (0.50 mL), ethyl cyanoacetate (1.13 g, 0.01 mol ), any of benzaldehyde (1.06 g, 0.01 mol), 4-methoxybenzaldehyde (1.36 g, 0.01 mol) or 4-chlorobenzaldehyde (1.41 g, 0.01 mol) was added. The reaction mixture in each case was heated under reflux for 4 h then poured onto ice/water containing few drops of hydro- chloric acid and the formed solid product was collected by fil- tration.

Compound 6a: Brown crystals from ethanol, yield 63 % (2.08 g), m.p 287 °C. Anal. Calculated for C20H15N3O2 (329.35): C, 72.94; H, 4.59; N, 12.76. Found: C, 73.13; H, 4.55; N; 12.46.

MS: m/e 329 (M+, 16 %), IR, υ: 3523-3318 (OH, NH), 3056 (CH,

aromatic), 2228, 2220 (2CN), 1638 (C=C). 1H NMR (DMSO-d6,

200 MHz): δ = 3.13 (s, 3H, CH3), 6.12 (s, 1H, pyran H-4), 7.28-

7.39 (m, 9H, C6H5, C6H4), 8.32 (s, 1H, D2O exchangeable, NH),

10.28 (s, 1H, D2O exchangeable, OH). 13C NMR (DMSO-d6, 75

MHz): δ = 19.8 (CH ), 80.6 (pyran C-4), 116.4, 116.7 (2CN),

g), m.p>300°C. Anal. Calculated for C H N O (328.37): C, 3

20 16 4

73.15; H, 4.91; N, 17.06. Found: C, 73.08; H, 5.11; N; 16.89. MS:

m/e 328 (M+, 22 %), IR, υ: 3472-3332 (NH2, NH), 3054 (CH,

120.3, 120.5, 121.4, 122.5, 123.8, 124.9, 126.1, 127.4, 128.5,

129.6, 130.0, 132.6 (C6H5, C6H4, pyran C).

aromatic), 2227, 2222 (2CN), 1632 (C=C). 1H NMR (DMSO-d6,

200 MHz): δ = 3.11 (s, 3H, CH3), 4.82 (s, 2H, D2O exchangeable,

NH2), 6.05 (s, 1H, pyran H-4), 7.28-7.39 (m, 9H, C6H4,C6H5),

8.29 (s, 1H, D O exchangeable, NH). 13C NMR (DMSO-C H , 75

Compound 6b: Yellow crystals from ethanol, yield 67 % (2.40 g), m.p172 °C. Anal. Calculated for C21H17N3O3 (359.38): C, 70.18; H, 4.77; N, 11.69. Found: C, 70.23; H, 4.80; N; 11.72. MS:

m/e 359 (M+, 28 %), IR, υ: 3520-3321 (OH, NH), 3056 (CH, aro-

2 6 4

MHz): δ = 19.6 (CH3), 80.4 (pyran C-4), 116.8, 117.0 (2CN),

119.3, 119.8, 120.2, 120.6, 122.4, 125.3, 126.0, 128.6, 129.8,

130.1, 132.2, 132.3 (C6H5, C6H4, pyran C).

Compound 4b: Yellow crystals from ethanol yield 56 %

matic), 2228, 2220 (2CN), 1632 (C=C). 1H NMR (DMSO-d6, 200

MHz): δ = 3.16 (s, 3H, CH3), 3.14 (s, 3H, OCH3), 6.13 (s, 1H, pyran

H-4), 7.28-7.36 (m, 8H, 2C6H4), 8.28 (s, 1H, D2O exchangeable, NH), 10.20 (s, 1H, D2O exchangeable, OH). 13C NMR (DMSO-d6,

75 MHz): δ = 19.6, 24.1 (CH , OCH ), 80.4 (pyran C-4), 116.6,

(2.00 g), m.p 165 °C. Anal. Calculated for C H N O (358.39): 3 3

21 18 4 2

C, 70.38; H, 5.06; N, 15.63. Found: C, 70.19; H, 5.20; N; 15.83.

117.2 (2CN), 120.1, 120.2, 121.6, 122.5, 124.0, 124.5, 126.1,

127.8, 129.0, 129.4, 130.3, 131.9 (2 C H , pyran C).

6 4

MS: m/e 358 (M+, 16 %), IR, υ: 3478-3328 (NH2, NH), 3054

(CH, aromatic), 2226, 2222 (2CN), 1631 (C=C). 1H NMR (DM- SO-d6, 200 MHz): δ = 3.09, 3.20 (2s, 6H, 2CH3), 4.86 (s, 2H, D2O

exchangeable, NH2), 6.08 (s, 1H, pyran H-4), 7.26-7.45 (m,

8H, 2C H ), 8.26 (s, 1H, D O exchangeable, NH). 13C NMR (DM-

Compound 6c: Yellow crystals from ethanol, yield 63 % (2.27 g), m.p> 300°C. Anal. Calculated for C20H14ClN3O2 (363.80): C, 66.03; H, 3.88; N, 11.55. Found: C, 66.18; H, 4.02;

N; 11.63. MS: m/e 363 (M+, 22 %), IR, υ: 3520-3308 (OH, NH),

6 4 2

SO-C H ,75 MHz): δ = 19.4 , 24.6 (CH , OCH ), 80.4 (pyran C-4), 3056 (CH, aromatic), 2224, 2220 (2CN), 1633(C=C). 1H NMR

6 4 3 3

116.8, 117.0 (2CN), 119.6, 119.9, 120.4, 120.5, 122.0, 125.8,

(DMSO-d6, 200 MHz): 3.09 (s, 3H, CH3), 6.11 (s, 1H, pyran H-4),

7.26-7.37 (m, 8H, C6H4, C6H4), 8.13 (s, 1H, D2O exchangeable,

NH), 9.88 (s, 1H, D2O exchangeable, OH).

2-Amino-4-phenyl-6-(p-tolylamino)-1,4-dihydropyridine-3,5-di- carbonitrile (7a), 2-hydroxy-4-phenyl-6-(p-tolylamino)-1,4-di- hydropyridine-3,5-dicarbonitrile (7b), 2-amino-4-(4-methoxy-

Compound 7d: Yellow crystals from ethanol, yield 77 % (2.75 g), m.p179 °C. Anal. Calculated for C21H18N4O2 (358.39): C, 70.38; H, 5.06; N, 15.63. Found: C, 70.44; H, 5.28; N; 15.52.

MS: m/e 358 (M+, 18 %), IR, υ: 3553-3338 (OH, 2NH), 3056 (CH, aromatic), 2228, 2220 (2CN), 1638 (C=C). 1H NMR (DM- SO-d , 200 MHz): δ = 3.08, 3.12 (2s, 6H, 2CH ), 6.11 (s, 1H, pyr-

phenyl)-6-(p-tolylamino)-1,4-dihydropyridine-3,5-dicarbonitrile 6 3

(7c), 2-hydroxy-4-(4-methoxyphenyl)-6-(p-tolylamino)-1,4-di- hydropyridine-3,5-dicarbonitrile (7d), 2-amino-4-(4-chloro- phenyl)-6-(p-tolylamino)-1,4-dihydropyridine-3,5-dicarbo- nitrile(7e),and4-(4-chlorophenyl)-2-hydroxy-6-(p-tolylami- no)-1,4-dihydropyridine-3,5-dicarbonitrile (7f)

General procedure: To a solution of compound 1 (1.74 g, 0.01 mol) in ethanol (50 mL) containing ammonium acetate (0.50 g), either of malononitrile (0.66 g, 0.01 mol ) or ethyl cyanoac- etate (1.13 g, 0.01 mol ), and any of benzaldehyde ( 1.06 g, 0.01 mol), 4-methoxybenzaldehyde (1.36 g, 0.01 mol) or 4-chloro- benzaldehyde (1.41 g, 0.01 mol) was added. The reaction mix-

idine H-4), 7.26-7.41 (m, 8H, 2C6H4), 8.13, 8.22 (2s, 2H, D2O

exchangeable, 2NH), 10.09 (s, 1H, D2O exchangeable, OH). 13C NMR (DMSO-d6, 75 MHz): δ = 19.6, 24.0 (CH3, OCH3), 80.6

(pyridine C-4), 116.6, 117.1 (2CN), 120.2, 120.4, 121.6, 122.5,

124.0, 124.8, 126.3, 127.8, 129.0, 129.6, 130.3, 131.9 (2 C6H4,

pyridine C).

Compound 7e: White crystals from ethanol, yield 60 % (2.17 g), m.p> 300 °C. Anal. Calculated for C20H16ClN5 (361.83): C, 66.39; H, 4.46; N, 19.36. Found: C, 66.59; H, 4.28; N; 19.04.

MS: m/e 361 (M+, 22 %), IR, υ: 3484-3313 (NH2, 2NH), 3056 (CH, aromatic), 2225, 2221 (2CN), 1632 (C=C). 1H NMR (DM- SO-d , 200 MHz): 3.11 (s, 3H, CH ), 4.83 (s, 2H, D O exchange-

ture in each case was heated under reflux for 4 h then poured 6 3 2

onto ice/water containing few drops of hydrochloric acid and

the formed solid product was collected by filtration.

Compound 7a: white crystals from ethanol, yield 64 % (2.09 g), m.p> 300 °C. Anal. Calculated for C H N (327.38): C, 73.37; H,

able, NH2), 6.11 (s, 1H, pyridine H-4), 7.26-7.41 (m, 8H, 2C6H4),

8.11, 8.28 (2s, 2H, D2O exchangeable, 2NH).

Compound 7f: White crystals from ethanol, yield 64 % (2.33 g), m.p 159 °C. Anal. Calculated for C20H15ClN4O (362.81):

20 17 5

5.23; N, 21.39. Found: C, 73.41; H, 5.08; N; 21.44. MS: m/e 327

(M+, 31 %), IR, υ: 3438-3315 (NH2, 2NH), 3056 (CH, aromatic), 2226, 2220 (2CN), 1634 (C=C). 1H NMR (DMSO-d6, 200 MHz):

C, 70.38; H, 5.06; N, 15.63. Found: C, 70.21; H, 5.17; N; 15.44.

MS: m/e 362 (M+, 23 %), IR, υ: 3529-3314 (OH, 2NH), 3052 (CH, aromatic), 2223, 2220 (2CN), 1632 (C=C). 1H NMR (DM- SO-d , 200 MHz): 3.16 (s, 3H, CH ), 6.13 (s, 1H, pyridine H-4),

δ = 3.16 (s, 3H, CH ), 4.89 (s, 2H, D O exchangeable, NH ), 6.14 6 3

3 2 2

7.27-7.39 (m, 8H, 2C6H4), 8.16, 8.24 (2s, 2H, D2O exchangeable,

(s, 1H, pyridine H-4), 7.26-7.35 (m, 9H, C6H5, C6H4), 8.33, 8.38

(2s, 2H, D O exchangeable, 2NH). 13C NMR (DMSO-d , 75 MHz):

2NH), 10.24 (s, 1H, D2O exchangeable, OH).

2 6

δ = 19.8 (CH3), 80.6 (pyridine C-4), 116.8, 117.0 (2CN), 120.3,

120.8, 121.3, 122.6, 123.3, 123.8, 124.8, 126.6, 127.8, 128.2,

128.9, 130.5 (C6H5, C6H4, pyridine C),.

Compound 7b: Yellow crystals from ethanol, yield 55 % (1.81 g), m.p 134 °C. Anal. Calculated for C20H16N4O (328.37): C, 73.15; H, 4.91; N, 17.06. Found: C, 73.08; H, 4.88; N; 16.93. MS:

m/e 328 (M+, 22 %), IR, υ: 3538-3341 (OH, 2NH), 3057 (CH,

aromatic), 2226, 2220 (2CN), 1634 (C=C). 1H NMR (DMSO-d6,

200 MHz): δ = 3.14 (s, 3H, CH3), 6.15 (s, 1H, pyridine H-4), 7.25-

7.39 (m, 9H, C6H5, C6H4), 8.26, 8.32 (2s, 2H, D2O exchangeable,

2NH), 10.19 (s, 1H, D2O exchangeable, OH). 13C NMR (DMSO-d6,

75 MHz): δ = 19.6 (CH3), 80.4 (pyridine C-4), 116.6, 116.9

(2CN), 120.2, 120.6, 121.1, 122.8, 123.6, 123.8, 124.3, 126.4,

127.7, 128.2, 128.5, 130.2 (C6H5, C6H4, puridine C).

Compound 7c: Yellow crystals from ethanol, yield 88 % (3.13 g), m.p 157 °C. Anal. Calculated for C21H19N5O (357.41): C, 70.57; H, 5.36; N, 19.59. Found: C, 70.62; H, 5.41; N; 19.77. MS:

m/e 357 (M+, 16 %), IR, υ: 3484-3323 (NH2, 2NH), 3053 (CH,

aromatic), 2226, 2221 (2CN), 1636 (C=C). 1H NMR (DMSO-d6,

200 MHz): 2.99 (s, 3H, CH3), 3.14 (s, 3H, OCH3), 4.82 (s, 2H, D2O

exchangeable, NH2), 6.13 (s, 1H, pyridine H-4), 7.23-7.39 (m,

8H, 2C6H4), 8.16, 8.20 (2s, 2H, D2O exchangeable, 2NH).

2-Amino-4-(furan-2-yl)-6-(p-tolylamino)-4H-pyran-3,5-dicar- bonitrile (9a) and 4-(furan-2-yl)-2-hydroxy-6-(p-tolylamino)- 4H-pyran-3,5-dicarbonitrile (9b)

General procedure: To a solution of compound 1 (1.74 g, 0.01 mol) in ethanol (50 mL) containing triethylamine (0.50 mL), furfural (0.96 g, 0.01 mol), either of malononitrile (0.66 g, 0.01 mol ) or ethyl cyanoacetate (1.13g, 0.01 mol ) was added. The reaction mixture in each case was heated under reflux for 4 h then poured onto ice/water containing few drops of hydro- chloric acid and the formed solid product was collected by fil- tration.

Compound 9a: Reddish brown crystals from ethanol, yield 60 % (1.92 g), m.p 187 °C. Anal. Calculated for C18H14N4O2 (318.33): C, 67.91; H, 4.43; N, 17.60. Found: C, 67.62; H, 4.60;

N; 17.49. MS: m/e 318 (M+, 28 %), IR, υ: 3489-3342 (NH2, NH),

3059 (CH, aromatic), 2222, 2220 (2CN), 1636 (C=C). 1H NMR

(DMSO-d6, 200 MHz): δ = 3.13 (s, 3H, CH3), 4.22 (s, 2H, D2O-

exchangeable, NH2), 6.18 (s, 1H, pyran H-4), 7.22-7.45 (m, 7H, C6H4, furfuryl H), 8.16 (s, 1H, D2O exchangeable, NH). 13C NMR (DMSO-d6, 75 MHz): δ = 19.6 (CH3), 80.6 (pyran C-4), 116.4,

117.0 (2CN), 120.3, 121.8, 121.9, 122.4, 124.3, 127.4, 128.5,

129.8, 130.3, 138.2, 138.6, 140.3 (C6H4, furan, pyran C).

Compound 9b: Brown crystals from ethanol, yield 60 % (1.93 g), m.p 90°C. Anal. Calculated for C18H13N3O3 (319.31): C, 67.71; H, 4.10; N, 13.16. Found: C, 67.88; H, 4.28; N; 13.39. MS:

m/e 319 (M+, 20 %), IR, υ: 3520-3322 (OH, NH), 3055 (CH, aro-

matic), 2225, 2220 (2CN), 1638 (C=C). 1H NMR (DMSO-d6, 200

MHz): 3.12 (s, 3H, CH3), 6.17 (s, 1H, pyran H-4), 7.26-7.41(m,

7H, C H , furfuryl H), 8.13 (s, 1H, D O exchangeable, NH), 10.25

poured onto ice/water containing few drops of hydrochloric

acid and the formed solid product was collected by filtration.

Compound 12: Greenish yellow crystals from ethanol, yield 67 % (1.91 g), m.p 261 °C. Anal. Calculated for C16H18N2OS (286.39): C, 67.10; H, 6.33; N, 9.78; S, 11.20. Found: C, 67.22;

H, 6.19; N, 9.83; S, 11.04. MS: m/e 286 (M+, 19 %), IR, υ: 3477-

6 4 2

(s, 1H, D2O exchangeable, OH).

2-Amino-4-(furan-2-yl)-6-(p-tolylamino)-4H-pyridine-3,5-di- carbonitrile (10a) and 4-(furan-2-yl)-2-hydroxy-6-(p-tolylami- no)-4H-pyridine-3,5-dicarbonitrile (10b)

General procedure: To a solution of compound 1 (1.74 g, 0.01 mol) in ethanol (50 mL) containing ammonium acetate (0.50 mL) furfural (0.96 g, 0.01 mol), either of malononitrile (0.66 g,

0.01 mol ) or ethyl cyanoacetate (1.13g, 0.01 mol ) was added. The reaction mixture in each case was heated under reflux for 3 h then poured onto ice/water containing few drops of hy- drochloric acid and the formed solid product was collected by filtration.

Compound 10a: Reddish brown crystals from ethanol, yield 64 % (2.04 g), m.p 183 °C. Anal. Calculated for C18H15N5O (317.34): C, 68.13; H, 4.76; N, 22.07. Found: C, 67.93; H, 4.82;

N; 21.99. MS: m/e 317 (M+, 32 %), IR, υ: 3449-3312 (NH2,

2NH), 3054 (CH, aromatic), 2226, 2222 (2CN), 1631 (C=C). 1H

NMR (DMSO-d6, 200 MHz): δ = 3.13 3.16 (s, 3H, CH3), 4.24 (s,

2H, D2O exchangeable, NH2), 6.15 (s, 1H, pyridineH-4), 7.26-

7.38 (m, 7H,C6H4, furfuryl H), 8.14, 8.29 (2s, 2H, D2O exchange-

able, 2NH). 13C NMR (DMSO-d , 75 MHz): δ = 19.8 (CH ), 80.3

3321 (NH2, NH), 2981, 2859 (CH3, CH2), 1689 (CO), 3055 (CH, aromatic),1634 (C=C). 1H NMR (DMSO-d6, 200 MHz): δ = 1.62-1.84 (m, 4H, 2CH2), 2.21-2.38 (m, 4H, 2CH2), 3.02 (s, 3H, CH3), 5.83 (s, 2H, D2O exchangeable, NH2), 7.26-7.36 (2d, 4H, C6H4), 8.26 (s, 1H, D2O exchangeable, NH). 13C NMR (DMSO-d6, 75 MHz): δ = 19.6 (CH3), 22.8, 26.4, 28.2, 29.6 (4CH2), 118.3,

120.4, 122.7, 126.9, 130.3, 133.2, 134.6, 138.2 (C6H4, thiophene

C), 164.8 (CO).

2-(Benzylideneamino)-N-(p-tolyl)-4,5,6,7-tetrahydroben- zo[b]thiophene-3-carboxamide (13a) and 2-((4-methoxyben- zylidene)amino)-N-(p-tolyl)-4,5,6,7- tetrahydrobenzo [b]thio- phene-3-carboxamide (13b)

To a solution of compound 12 (2.86 g, 0.01 mol) in 1,4-dioxane (50 mL) containing piperidine (0.50 mL) any of benzaldehyde (1.06 g, 0.01 mol) or 4-methoxybenzaldehyde (1.36 g, 0.01 mol) was added. The reaction mixture was heated under reflux for 3 h then poured onto ice/water containing few drops of hy- drochloric acid and the formed solid product was collected by filtration.

Compound 13a: Orange crystals from 1,4-dioxane, yield 76 % (2.86 g), m.p 184 °C. Anal. Calculated for C23H22N2OS (374.50):

6 3 C, 73.76; H, 5.92; N, 7.48; S, 8.56. Found: C, 73.56; H, 6.03; N;

(pyridine C-4), 116.1, 117.0 (2CN), 119.4, 121.8, 121.9, 124.8,

126.9, 130.4, 132.5, 133.1, 134.7, 136.8, 138.6, 140.4 (C H ,

7.59; S, 8.67. MS: m/e 374 (M+, 28 %), IR, υ: 3433, 3339 (NH),

furan, pyridine C).

6 4 3056 (CH, aromatic), 1688 (CO), 1631 (C=C). 1H NMR (DM- SO-d6, 200 MHz) (DMSO-d6, 200 MHz): δ = 1.60-1.86 (m, 4H,

Compound 10b: Yellow crystals from ethanol, yield 88 %

(2.78 g), m.p 150 °C. Anal. Calculated for C18H14N4O2 (318.33): C, 67.91; H, 4.43; N, 17.60. Found: C, 67.79; H, 4.36; N; 17.42.

MS: m/e 318 (M+, 14 %), IR, υ: 3593-3338 (OH, 2NH), 3053 (CH, aromatic), 2228, 2222 (2CN), 1633 (C=C). 1H NMR (DM- SO-d6, 200 MHz), δ: 3.15 (s, 3H, CH3), 6.19 (s, 1H, pyridine H-4),

7.22-7.39 (m, 7H, C6H4, furfuryl H), 8.16, 8.27 (2s, 2H, D2O ex-

changeable, 2NH), 10.34 (s, 1H, D O exchangeable, OH). 13C

2CH2), 2.23-2.39 (m, 4H, 2CH2), 3.11 (s, 3H, CH3), 6.22 (s, 1H,

N=CH), 7.28- 7.39 (m, 9H, C6H5, C6H4), 8.24 (s, 1H, D2O ex- changeable, NH). 13C NMR (DMSO-d6, 75 MHz): δ = 19.9 (CH3), 22.6, 26.6, 28.4, 29.2 (4CH2), 120.3, 120.8, 121.4, 124.3, 126.7,

128.0, 129.3, 129.5, 133.5, 134.4, 138.6 (C6H5, C6H4, thiophene

C), 164.8 (CO), 168.9 (C=N).

Compound 13b: Orange crystals from 1,4-dioxane, yield

2 82 % (3.318 g), m.p 228 °C. Anal. Calculated for C H

N O S

NMR (DMSO-d6, 75 MHz): δ = 19.6 (CH3), 80.2 (pyridine C-4),

24 24 2 2

116.6, 116.9 (2CN), 119.4, 120.3, 121.9, 125.0, 126.9, 130.4,

131.8, 133.1, 134.7, 136.8, 138.8, 140.4 (C H , furan, pyridine

(404.52): C, 71.26; H, 5.98; N, 6.93; S, 7.93. Found: C, 71.36; H,

6.11; N; 6.82; S, 8.04. MS: m/e 404 (M+, 17 %), IR, υ: 3463, 3316

C).

6 4 (NH), 3053 (CH, aromatic), 1689 (CO), 1636 (C=C). 1H NMR (DMSO-d6, 200 MHz): δ = 1.63-1.86 (m, 4H, 2CH2), 2.23-2.41

2-Amino-N-(p-tolyl)-4,5,6,7-tetrahydrobenzo[b]thio-

phene-3-carboxamide (12)

To a solution of compound 1 (1.74 g, 0.01 mol) in ethanol (50 mL) containing triethylamine (0.50 mL) elemental sulfur (0.32 g, 0.01 mol) and cyclohexanone (0.98 g, 0.01 mol) were add- ed. The reaction mixture was heated under reflux for 1 h then

(m, 4H, 2CH2), 3.08, 3.24 (2s, 6H, 2CH3), 6.24 (s, 1H, N=CH),

7.29-7.42 (m, 8H, 2C6H4), 8.26 (s, 1H, D2O exchangeable, NH).

13C NMR (DMSO-d6, 75 MHz): δ = 19.8, 24.3 (CH3, OCH3), 22.5,

26.6, 28.4, 29.4 (4CH2), 120.8, 121.2, 121.4, 124.2, 126.7,

128.3, 129.3, 129.5, 133.7, 134.4, 138.9 (C6H5, C6H4, thiophene

C), 164.5 (CO), 168.6 (C=N).

2-(2-Chloroacetamido)-N-(p-tolyl)-4,5,6,7-tetrahydrobenzo[b] thiophene-3-carboxamide (15)

To a solution of compound 12 (2.86 g, 0.01 mol) in 1,4-diox- ane (50 mL) containing chloroacetylchloride (1.12 g, 0.01 mol) was added. The whole reaction mixture was heated under re- flux for 6 h then poured onto ice/water containing few drops of hydrochloric acid and the formed solid product was collect-

Compound 19: Reddish brown crystals from ethanol, yield 65 % (3.158 g), m.p> 300 °C. Anal. Calculated for C28H29N3OS2 (487.68): C, 68.96; H, 5.99; N, 8.62; S, 13.15. Found: C, 68.80;

H, 5.73; N; 8.47; S, 12.83. MS: m/e 503 (M+, 26 %), IR, υ: 3463-

3316 (NH), 3056 (CH, aromatic), 1688 (CO), 1643 (C=C), 1212 (C=S). 1H NMR (DMSO-d6, 200 MHz): δ = 1.60-1.84 (m, 4H, 2CH2), 2.20-2.38 (m, 4H, 2CH2), 2.87, 3.05, 3.13 (3s, 9H, 3CH3),

6.22 (m,2H, pyrimidine H-4, H-5), 7.28-7.36 (m, 9H, C H ,

6 5

ed by filtration.

C6H4), 8.28 (s, 1H, D O exchangeable, NH). 13C NMR (DMSO-d ,

2 6

Compound 15: Brown crystals from 1,4-dioxane, yield 63

% (2.29 g), m.p 212 °C. Anal. Calculated for C H ClN O S

75 MHz): δ = 16.8, 17.3, 19.6 (3CH3), 22.4, 26.8, 28.3, 29.5

(4CH2), 120.3, 121.2, 121.4, 124.6, 126.4, 128.2, 129.0, 129.7,

18 19 2 2

130.8, 134.4, 138.8 140.2, 141.8, 142.4 (C6H5, C6H4, pyridine,

(362.87): C, 59.66; H, 5.28; N, 7.72; S, 8.8. Found: C, 59.36; H,

5.51; N; 7.82; S, 8.04. MS: m/e 362 (M+, 16 %), IR, υ: 3454-3326

(2NH), 3058 (CH, aromatic), 1702, 1686 (2CO), 1630 (C=C).

1H NMR (DMSO-d6, 200 MHz): δ = 1.60-1.84 (m, 4H, 2CH2),

2.22-2.40 (m, 4H, 2CH2), 3.15 (s, 3H, CH3), 5.24 (s, 2H, CH2),

7.25-7.39 (2d, 4H, C6H4), 8.24, 8.30 (2s, 2H, D2O exchangeable,

2NH). 13C NMR (DMSO-d6, 75 MHz): δ = 19.6 (CH3), 22.4, 26.7,

28.4, 29.1 (4CH2), 64.3 (CH2), 120.8, 121.4, 124.3, 126.7, 128.0,

133.5, 134.4, 138.6 (C6H4, thiophene C), 164.3, 165.2 (2CO).

2-(3-Phenylthioureido)-N-(p-tolyl)-4,5,6,7-tetrahydrobenzo[b] thiophene-3-carboxamide (17)

To a solution of compound 12 (2.86 g, 0.01 mol) in 1,4-diox- ane (50 mL) phenylisothiocyanate (1.35 g, 0.01 mol) was add- ed. The reaction mixture was heated under reflux for 4 h then evaporated under vacuum and the remaining product was trit- urated with ethanol and the formed solid product was collect- ed by filtration.

Compound 17: Brown crystals from 1,4-dioxane, yield 61

thiophene C), 164.5 (CO), 168.6 (C=N).

2-((4-Methyl-3-phenylthiazol-2(3H)-ylidene)amino)-N-(p- tolyl)-4,5,6,7- tetrahydrobenzo [b]thiophene-3-carboxamide (21a) and 2-((4-hydroxy-3-phenylthiazol-2(3H)-ylidene)ami- no)-N-(p-tolyl)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbox- amide (21b)

General procedure: To a solution of compound 17 (4.21 g,

0.01 mol) in ethanol (50 mL), either of α-chloroacetone (0.92 g, 0.01 mol) or α -chloroethyl acetate (1.22 g, 0.01 mol) was added. The reaction mixture, in each case, was heated under reflux for 2 h then left to cool and the formed solid product was collected by filtration.

Compound 21a: Greenish yellow crystals from ethanol, yield 55 % (2.53 g), m.p 151 °C. Anal. Calculated for C26H25N3OS2 (459.63): C, 67.94; H, 5.48; N, 9.14; S, 13.95. Found: C, 67.85;

H, 5.62; N; 9.05; S, 14.18. MS: m/e 459 (M+, 22 %), IR, υ: 3474-

3329 (NH), 3053 (CH, aromatic), 1687 (CO), 1632 (C=C). 1H NMR (DMSO-d , 200 MHz): δ = 1.62-1.86 (m, 4H, 2CH ), 2.21-

% (2.567 g), m. p 245 °C. Anal. Calculated for C H N OS 6 2

23 23 3 2 2.39 (m, 4H, 2CH2), 3.02, 3.14 (2s, 6H, 2CH3), 6.02 (s, 1H, thi-

(421.58): C, 65.53; H, 5.50; N, 9.97; S, 15.21. Found: C, 65.72;

H, 5.82; N; 10.13; S, 15.35. MS: m/e 421 (M+, 38 %), IR, υ: 3450-

3329 (3NH), 3058 (CH, aromatic), 1686 (CO), 1642 (C=C),

1205 (C=S). 1H NMR (DMSO-d6, 200 MHz): δ = 1.62-1.84 (m,

4H, 2CH2), 2.20-2.37 (m, 4H, 2CH2), 3.12 (s, 3H, CH3), 7.26-7.39

azole H-5), 7.26-7.39 (m, 9H, C6H5, C6H4) , 8.25 (s, 1H, D2O

exchangeable, NH). 13C NMR (DMSO-d6, 75 MHz): δ = 18.8, 19.3 (2CH3), 22.8, 26.3, 28.2, 29.5 (4CH2), 120.6, 122.7, 123.8,

126.2, 126.9, 127.0, 127.8, 128.5, 129.2, 133.5, 134.2, 135.6,

136.8, 140.2 (C H , C H , thiazole, thiophene C), 164.4 (CO),

(m, 9H, C H , C H ), 8.26, 8.32, 8.36 (3s, 3H, D O exchangeable,

6 5 6 4

6 5 6 4

2 172.8 (C=N).

3NH). 13C NMR (DMSO-d6, 75 MHz): δ = 19.4 (CH3), 22.5, 26.4,

28.4, 29.2 (4CH2), 120.3, 120.9, 124.3, 125.4, 126.7, 127.0,

127.9, 128.0, 129.4, 133.5, 136.7, 138.9 (C6H5, C6H4, thiophene

Compound 21b: Gray crystals from ethanol, yield 56 % (2.6 g), m.p 217 °C. Anal. Calculated for C H N O S (461.60): C,

C), 164.2, (CO), 173.6 (C=S).

2-(4,6-Dimethyl-2-thioxopyrimidin-1(2H)-yl)-N-(p-tol yl)-4,5,6,7- tetrahydrobenzo[b] thiophene-3-carboxamide (19)

25 23 3 2 2

65.05; H, 5.02; N, 9.10; S, 13.89. Found: C, 64.82; H, 5.14; N;

9.24; S, 14.04. MS: m/e 461 (M+, 15 %), IR, υ: 3523-3320 (OH, NH), 3056 (CH, aromatic), 1688 (CO), 1630 (C=C). 1H NMR (DMSO-d , 200 MHz): δ = 1.62-1.86 (m, 4H, 2CH ), 2.21-2.39

6 2

To a solution of compound 17 (4.21 g, 0.01 mol) in ethanol (50 mL) containing piperidine (0.50 mL), acetylacetone (1.0 g,

0.01 mol) was added. The reaction mixture was heated under reflux for 3 h then evaporated under vacuum and the remain- ing product was triturated with ethanol and the formed solid product was collected by filtration.

(m, 4H, 2CH2), 3.14 (s, 3H, CH3), 6.02 (s, 1H, thiazole H-5), 7.26-7.39 (m, 9H, C6H5, C6H4), 8.28 (s, 1H, D2O exchangeable, NH), 10.08 (s, 1H, D2O exchangeable, OH). 13C NMR (DMSO-d6, 75 MHz): δ = 19.5 (2CH3), 22.8, 26.3, 28.2, 29.3 (4CH2), 120.3,

122.9, 123.5, 126.4, 126.9, 127.0, 127.3, 128.8, 129.6, 133.8,

134.5, 135.6, 136.8, 140.5 (C6H5, C6H4, thiazole, thiophene C),

164.3 (CO), 172.6 (C=N).

2-((4-(4-Chlorophenyl)-3-phenylthiazol-2(3H)-ylidene)ami-

no)-N-(p-tolyl)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbox- amide (23)

To a solution of compound 17 (4.21 g, 0.01 mol) in ethanol (50 mL), ⍵-bromo-4-chloroacetophenone (2.33 g, 0.01 mol) was added. The reaction mixture, in each case, was heated under reflux for 4 h then left to cool and the formed solid product was collected by filtration.

Compound 23: Yellow crystals from ethanol, yield 57 %

the formed solid product was collected by filtration.

Compound 26: Yellow crystals from ethanol, yield 97 % (4.52 g), m.p> 300 °C. Anal. Calculated for C24H23ClN4O2S (466.98): C, 61.73; H, 4.96; N, 12.00; S, 6.87. Found: C,

61.92; H, 5.25; N; 11.83; S, 6.92. MS: m/e 466 (M+, 20 %),

IR, υ: 3473-3322 (3 NH), 3054 (CH, aromatic), 1689, 1703 (2CO), 1632 (C=C). 1H NMR (DMSO-d6, 200 MHz): δ = 1.59- 1.84 (m, 4H, 2CH2), 2.20-2.39 (m, 4H, 2CH2), 3.11 (s, 3H,

CH ), 7.22-7.40 (m, 9H, C H , C H ), 8.21, 8.26, 8.32 (3s, 3H,

3 6 5 6 4

(3.16 g), m.p 174 °C. Anal. Calculated for C31H26ClN3OS2

(556.14): C, 66.95; H, 4.71; N, 7.56; S, 11.53. Found: C, 67.16;

H, 4.52; N; 7.69; S, 11.72. MS: m/e 556 (M+, 38 %), IR, υ: 3482-

3320 (NH), 3056 (CH, aromatic), 1690 (CO), 1631 (C=C). 1H NMR (DMSO-d , 200 MHz): δ = 1.63-1.88 (m, 4H, 2CH ), 2.20-

D2O exchangeable, 3NH). 13C NMR (DMSO-d6, 75 MHz): δ = 19.5 (CH3), 22.4, 26.3, 28.0, 29.5 (4CH2), 120.4, 121.9, 123.6,

124.2, 125.4, 126.8, 127.3, 128.6, 129.2, 131.8, 132.8, 135.3,

(C6H5, C6H4, thiophene C), 162.3, 164.3 (2CO), 172.3 (C=N).

6 2

2.37 (m, 4H, 2CH2), 3.11 (s, 3H, CH3), 6.08 (s, 1H, thiazole H-5),

7.28-7.37 ( m, 13H, C6H5, 2C6H4), 8.26 (s, 1H, D2O exchangeable, NH). 13C NMR (DMSO-d6, 75 MHz): δ = 19.2 (CH3), 22.6, 26.3,

28.2, 29.6 (4CH2), 120.3, 121.9, 123.6, 124.8, 125.6, 126.8,

127.8, 128.2, 128.6, 129.2, 130.4, 130.3, 131.8, 132.8, 135.3,

136.3, 140.6 (C6H5, 2C6H4, thiazole, thiophene C), 164.3 (CO),

172.3 (C=N).

2-((2-Aminothiazol-4-yl)amino)-N-(p-tolyl)-4,5,6,7-tetrahydro- benzo-[b]thiophene-3-carboxamide (25)

To a solution of compound 15 (3.62 g, 0.01 mol) in ethanol (50 mL), thiourea (0.76 g, 0.01 mol) was added. The reaction mix- ture was heated under reflux for 2 h then left to cool and the formed solid product was collected by filtration.

Compound 25: Brown crystals from ethanol, yield 66 %

2-(2-Chloro-3-(2-hydroxyphenyl)acrylamido)-N-(p-tolyl)- 4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxamide (28)

To a solution of compound 15 (3.62 g, 0.01 mol) in ethanol (50 mL) containing piperidine (0.50 mL), salicylaldehyde (1.22 g,

0.01 mol) was added. The reaction mixture was heated under reflux for 3 h and the solid product, so formed, upon pouring onto ice/water mixture containing few drops of hydrochloric acid was collected by filtration.

Compound 28: Yellow crystals from ethanol, yield 97 % (4.52 g), m.p 200 °C. Anal. Calculated for C25H23ClN2O3S (466.98): C, 64.30; H, 4.96; N, 6.00; S, 6.87. Found: C, 64.55;

H, 4.86; N; 5.83; S, 6.59. MS: m/e 466 (M+, 12 %), IR, υ: 3532-

3314 (OH, 2NH), 3053 (CH, aromatic), 1690 , 1702 (2CO),

1632 (C=C). 1H NMR (DMSO-d6, 200 MHz): δ = 1.62-1.82 (m,

4H, 2CH ), 2.23-2.37 (m, 4H, 2CH ), 3.09 (s, 3H, CH ), 5.93 (s,

(2.53 g), m.p 204 °C. Anal. Calculated for C H N OS

(384.52): 2 2 3

19 20 4 2

1H, CH=C), 7.25-7.36 (m, 8H, 2C6H4 ), 8.23, 8.30 (2s, 2H, D2O

C, 59.35; H, 5.24; N, 14.57; S, 16.68. Found: C, 59.27; H, 5.05;

N; 14.29; S, 16.83. MS: m/e 384 (M+, 100 %), IR, υ: 3487-3340 (NH2, 2NH), 3056 (CH, aromatic), 1688 (CO), 1630 (C=C). 1H NMR (DMSO-d6, 200 MHz): δ = 1.61-1.88 (m, 4H, 2CH2), 2.20-

exchangeable, 2NH), 10.25 (s, 1H, D2O exchangeable, OH). 13C NMR (DMSO-d6, 75 MHz): δ = 19.4 (CH3), 22.6, 26.3, 28.0, 29.5

(4CH2), 86.8, 89.3 (C=CH), 120.2, 120.6, 124.2, 125.4, 126.8,

127.3, 131.8, 132.8, 135.3 (2 C H , thiophene C), 162.2, 164.5

2.37 (m, 4H, 2CH ), 3.13 (s, 3H, CH ), 4.28 (s, 2H, D O exchange- 6 4

2 3 2

able, NH2), 6.09 (s, 1H, thiazole H-5), 7.26-7.39 (2d, 4H, C6H4), 8.23, 8.29 (2s, 2H, D2O exchangeable, 2NH). 13C NMR (DMSO-d6,

75 MHz): δ = 19.4 (CH3), 22.6, 26.3, 28.2, 29.5 (4CH2), 120.3,

122.4, 123.8, 126.2, 126.5, 128.8, 129.2, 133.6, 135.4, 140.8

(C6H4, thiazole, thiophene C), 164.2 (CO), 173.5 (C=N).

2-Oxo-N’-phenyl-2-((3-(p-tolylcarbamoyl)-4,5,6,7-tetrahydro- benzo[b]thiophen-2-yl)amino)acetohydrazonoyl chloride (26)

To a cold solution of compound 15 (3.62 g, 0.01 mol) in ethanol (60 mL) containing sodium acetate (0.99 g in 10 mL water) at 0-5 oC a cold solution of benzenediazonium chloride [pre- pared by the addition of sodium nitrite solution (0.70 g, 0.01 mol) to a cold solution of aniline (0.93 g, 0.01 mol) in concen- trated hydrochloric acid (12 mL) with contineous stirring] was added with contineous stirring. The whole reaction mixture was stirred at room temperature for an additional 2 hours and

(2CO).

2-((6-Amino-3-chloro-5-cyano-4-phenyl-4H-pyran-2-yl)ami- no)-N-(p-tolyl)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-car- boxamide(29a),2-((6-amino-3-chrolo-5-cyano-4-(p-tolyl)- 4H-pyran-2-yl)amino-N-(p-tolyl)-4,5,6,7-tetrahydrobenzo[b] thiophene-3-carboxamide(29b)and2-((6-amino-3-chloro-4-(4- chlorophenyl)-5-cyano-4H-pyran-2-yl)amino)-N-(p-tolyl)-4,5,6,7

-tetrahydrobenzo[b]thiophene-3-carboxamide (29c)

General procedure: To a solution of compound 15 (3.62 g,

0.01 mol) in ethanol (50 mL) containing triethylamine (0.50 mL), malononitrile (0.66 g, 0.01 mol) and any of benzaldehyde (1.06 g, 0.01 mol), 4-methoxybenzaldehyde (1.36 g, 0.01 mol) or 4-chlorobenzaldehyde (1.41 g, 0.01 mol) were added. The reaction mixture was heated under reflux for 4 h then poured onto ice/water containing few drops of hydrochloric acid and the formed solid product was collected by filtration.

Compound 29a: Reddish brown crystals from ethanol, yield 70 % (3.62 g), m.p 181 °C. Anal. Calculated for C28H25ClN4O2S (517.04): C, 65.04; H, 4.87; N, 10.84; S, 6.20. Found: C, 65.32;

H, 4.93; N; 11.05; S, 6.36. MS: m/e 517 (M+, 28 %), IR, υ: 3488-

3342 (NH2, 2NH), 3056 (CH, aromatic), 2220 (CN), 1688 (CO),

1630 (C=C). 1H NMR (DMSO-d6, 200 MHz): 1.60-1.82 (m, 4H,

2CH2), 2.21-2.39 (m, 4H, 2CH2), 3.12 (s, 3H, CH3), 4.87 (s, 2H,

D2O exchangeable, NH2), 6.21 (s, 1H, pyran H-4), 7.26-7.42 (m,

9H, C6H5, C6H4), 8.24, 8.29 (2s, 2H, D2O exchangeable, 2NH).

Compound 29b: Brown crystals from ethanol, yield 66 % (3.62 g), m.p 162 °C. Anal. Calculated for C29H27ClN4O3S (547.07): C, 63.67; H, 4.97; N, 10.24; S, 5.86. Found: C, 63.77; H, 5.03; N;

(50 mL) triethylorthoformate (1.48 g, 0.01 mol) was added. The reaction mixture was heated under reflux for 3 h then evaporated under vacuum and the remaining product was trit- urated with ethanol and the formed solid product was collect- ed by filtration.

Compound 32: Brown crystals from acetic acid, yield 85 % (2.89 g), m.p 203 °C. Anal. Calculated for C19H22N2O2S (342.46): C, 66.64; H, 6.48; N, 8.18; S, 9.36. Found: C, 66.39; H, 6.61; N;

8.09; S, 9.22. MS: m/e 342 (M+, 20 %), IR, υ: 3470-3310 (NH),

3050 (CH, aromatic), 1688 (CO), 1630 (C=C). 1H NMR (DM- SO-d6, 200 MHz): 1.13 (t, 3H, J = 7.02 Hz, CH3), 1.54-1.80 (m,

4H, 2CH ), 2.21-2.39 (m, 4H, 2CH ), 3.10 (s, 3H, CH ), 3.80 (q,

10.29; S, 5.93. MS: m/e 547 (M+, 17 %), IR, υ: 3469-3331 (NH , 2 2 3

2

2NH), 3058 (CH, aromatic), 2222 (CN), 1688 (CO), 1630 (C=C).

2H, J = 7.02 Hz, CH2), 6.30 (s, 1H, CH=N), 7.23-7.43 (2d, 4H,

C H ), 8.26 (s, 1H, D O exchangeable, NH). 13C NMR (DMSO-d ,

1H NMR (DMSO-d , 200 MHz): 1.63-1.82 (m, 4H, 2CH ), 2.24- 6 4 2 6

6 2 75 MHz): δ = 16.8, 19.6 (2CH3), 22.8, 26.4, 28.2, 29.6 (4CH2),

2.37 (m, 4H, 2CH2), 3.11, 3.28 (2s, 6H, 2CH3), 4.83 (s, 2H, D2O

exchangeable, NH2), 6.23 (s, 1H, pyran H-4), 7.29-7.39 (m, 8H,

2C6H4), 8.23, 8.26 (2s, 2H, D2O exchangeable, 2NH).

Compound 29c: Brown crystals from ethanol, yield 66 % (3.62 g), m.p180 °C. Anal. Calculated for C28H24Cl2N4O2S (551.49): C, 60.98; H, 4.39; N, 10.16; S, 5.81. Found: C, 61.28; H, 4.28;

N; 10.22; S, 5.79. MS: m/e 551 (M+, 38 %), IR, υ: 3473-3326

(NH2, 2NH), 3056 (CH, aromatic), 2220 (CN), 1685 (CO), 1632 (C=C). 1H NMR (DMSO-d6, 200 MHz): 1.61-1.82 (m, 4H, 2CH2),

2.22-2.39 (m, 4H, 2CH2), 3.08 (s, 3H, CH3), 4.85 (s, 2H, D2O

exchangeable, NH2), 6.22 (s, 1H, pyran H-4), 7.31-7.42 (m, 8H,

2C6H4), 8.22, 8.28 (2s, 2H, D2O exchangeable, 2NH).

28.9 (OCH2), 118.6, 120.4, 122.7, 126.9, 130.3, 133.2, 134.6,

138.8 (C6H4, thiophene C), 164.6 (CO),170.2 (C=N).

2-(((Phenylamino)methylene)amino)-N-(p-tolyl)-4,5,6,7-tetra- hydrobenzo-[b]thiophene-3-carboxamide (34)

To a solution of compound 32 (3.42 g, 0.01 mol) in acetic acid (50 mL) aniline oil (0.93 g, 0.01 mol) was added. The reac- tion mixture was heated under reflux for 3 h then poured onto ice/water containing few drops of hydrochloric acid and the formed solid product was collected by filtration.

Compound 34: Brown crystals from acetic acid, yield 74 % (2.89 g), m.p150 °C. Anal. Calculated for C H N OS (389.51):

23 23 3

2-((4-amino-1-chloro-5-oxo-5,10b-dihydropyrano[3,4-c] chromen-2-yl)amino)-N-(p-tolyl)-4,5,6,7-tetrahydrobenzo[b] thiophene-3-carboxamide (30)

To a solution of compound 15 (3.62 g, 0.01 mol) in ethanol (50

C, 70.92; H, 5.95; N, 10.79; S, 8.23. Found: C, 71.11; H, 6.01;

N; 10.48; S, 8.04. MS:m/e 389 (M+, 16 %), IR, υ: 3472-3328 (2NH), 3053 (CH, aromatic), 1686 (CO), 1630 (C=C). 1H NMR (DMSO-d6, 200 MHz): 1.54-1.82 (m, 4H, 2CH2), 2.21-2.37 (m,

4H, 2CH ), 3.12 (s, 3H, CH ), 6.28 (s, 1H, CH=N), 7.25-7.40 (m,

2 3

mL) containing triethylamine (0.50 mL), malononitrile (0.66 g, 0.01 mol) and salicylaldehyde (1.22 g, 0.01 mol) were add- ed. The reaction mixture was heated under reflux for 4 h then poured onto ice/water containing few drops of hydrochloric acid and the formed solid product was collected by filtration.

Compound 30: Reddish brown crystals from ethanol, yield 85 % (4.52 g), m.p> 300 °C. Anal. Calculated for C28H24ClN3O4S (534.03): C, 62.97; H, 4.53; N, 7.87; S, 6.00. Found: C, 62.77; H,

4.38; N; 7.83; S, 6.28. MS: m/e 534 (M+, 22 %), IR, υ: 3483-3313

(NH2, 2NH), 3053 (CH, aromatic), 1703, 1688 (2CO), 1630 (C=C). 1H NMR (DMSO-d6, 200 MHz): 1.58-1.82 (m, 4H, 2CH2),

2.20-2.38 (m, 4H, 2CH2), 3.12 (s, 3H, CH3), 4.89 (s, 2H, D2O

exchangeable, NH2), 6.24 (s, 1H, pyran H-4), 7.28-7.40 (m, 8H,

2C6H4), 8.23, 8.30 (2s, 2H, D2O exchangeable, 2NH).

Ethyl N-(3-(p-tolylcarbamoyl)-4,5,6,7-tetrahydrobenzo[b]thio- phen-2-yl)formimidate (32)

To a solution of compound 12 (2.86 g, 0.01 mol) in acetic acid

9H, C6H5, C6H4), 8.28, 8.31 (2s, 2H, D2O exchangeable, 2NH).13C NMR (DMSO-d6, 75 MHz): δ = 19.5 (2CH3), 22.6, 26.4, 28.2, 29.4

(4CH2), 118.6, 119.8, 120.4, 122.7, 126.9, 128.7, 129.3, 130.3,

133.2, 134.6, 138.8 (C6H5, C6H4, thiophene C), 164.3 (CO), 170.6 (C=N).

Conclusion

In the current investigation, we have developed new and effi- cient methods for the synthesis of a variety of pyran, pyridine, thiophene, pyrimidine and thiazole derivatives. The antitumor activities of the newly synthesized product were evaluated against different tumor namely (MCF-7), (NCI-H460), (SF-268) where compounds 4b, 4c and 34 showed the highest inhibito- ry effect among the tested compounds through the cancer cell lines.

Acknowledgements

Ensaf Alwan would like to thank the Yemen Drug Company for industry and Commerce (YEDCO) in cooperation with the Min- istry of Higher Education on the continued support.

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