1062
S. Putatunda, A. Chakraborty / C. R. Chimie 17 (2014) 1057–1064
13C NMR (75 MHz, CDCl3):
d
166.6, 147.0, 145.6, 144.3,
(1 Â 50 mL). The organic layer was dried over anhydrous
129.8, 128.4, 127.4, 127.0, 123.5, 60.0, 34.1, 14.2.
IR (KBr, cmÀ1): 3280, 3236, 3101, 2970, 1652, 1494,
1338, 1273, 1157, 1100.
HRMS (ESI): m/z calcd for C21H21N3O4S + H+: 412.1331
[M + H+]; found: 412.1328.
Na2SO4 and removed under reduced pressure. The crude
mass was subjected to column chromatography using a
230–400 mesh silica gel when the desired product was
obtained by eluting the column with 30% EtOAc/60-80 8C
petroleum ether as the eluent.
Yield: 305 mg (84%); lemon-green solid; m.p. 215–
216 8C (ethyl acetate/n-hexane).
4.1.8. Ethyl 2-(hexadecylthio)-4-(4-methoxyphenyl)-6-
methyl-1,4-dihydropyrimidine-5-carboxylate (3.1a)
Yield: 425 mg (80%); colorless semi-solid.
1H NMR (300 MHz, DMSO-d6):
d 11.73 (brs, 1H; NH),
8.09 (d, J = 7.8 Hz, 1H; Ar–H), 7.94 (s, 1H; Ar–H), 7.63–7.53
(m, 2H; Ar–H), 6.36 (s, 1H; CH), 4.13–4.04 (m, 2H; ester
CH2), 2.58 (s, 3H; COCH3), 2.28 (s, 3H; CH3), 1.13 (t,
J = 7.2 Hz, 3H; ester CH3).
1H NMR (300 MHz, CDCl3):
d 7.26–7.23 (m, 3H; one H of
NH and two H of Ar–H), 6.82 (d, J = 8.7 Hz, 2H; Ar–H), 5.58
(s, 1H; CH), 4.11–4.07 (m, 2H; ester CH2), 3.79 (s, 3H;
OCH3), 3.30–3.11 (m, 2H; one–CH2–of n-hexadecyl), 2.99–
2.80 (m, 2H; one–CH2–of n-hexadecyl), 2.38 (s, 3H; CH3),
1.54–1.52 (m, 2H; one–CH2–of n-hexadecyl), 1.25–1.16
(m, 29H; thirteen–CH2–of n-hexadecyl and one ester CH3),
0.87 (t, J = 6.6 Hz, 3H;–CH3 of n-hexadecyl).
13C NMR (75 MHz, DMSO-d6):
d 178.0, 173.9, 165.1,
148.4, 146.2, 141.8, 133.2, 131.0, 123.5, 121.3, 106.9, 61.0,
53.0, 27.6, 17.0, 14.5.
IR (KBr, cmÀ1): 3252, 2993, 1706, 1673, 1525, 1362,
1287, 1224, 1095, 1042.
13C NMR (75 MHz, CDCl3):
d
166.8, 137.0, 128.0, 113.7,
HRMS (ESI): m/z calcd for C16H17N3O5S + Na+: 386.0787
[M + Na+]; found: 386.0787.
59.8, 55.2, 31.9, 31.2, 29.7, 29.7, 29.5, 29.4, 29.1, 28.7, 22.7,
14.3, 14.1.
IR (KBr, cmÀ1): 3298, 2924, 2855, 1655, 1607, 1504,
1245, 1167, 1095.
4.2.1. Ethyl 3-benzoyl-6-methyl-4-(3-nitrophenyl)-2-thioxo-
1,2,3,4-tetrahydropyrimidine-5-carboxylate (1.2b)
Yield: 306 mg (72%); lemon-green solid; m.p. 165–
166 8C (ethyl acetate/n-hexane).
HRMS (ESI): m/z calcd for C31H50N2O3S + H+: 531.3620
[M + H+]; found: 531.3613.
1H NMR (300 MHz, CDCl3):
d 8.27 (s, 1H; Ar–H), 8.18-
4.1.9. Ethyl 4-(4-methoxyphenyl)-6-methyl-2-{(4-
nitrobenzyl)thio}-1,4-dihydropyrimidine-5-carboxylate
(3.1b)
8.16 (m, 2H; one H of NH and one H of Ar–H), 7.84 (d,
J = 7.5 Hz, 1H; Ar–H), 7.68–7.65 (m, 2H; Ar–H), 7.57–7.50
(m, 2H; Ar–H), 7.40 (t, J = 7.8 Hz, 2H; Ar–H), 6.29 (s, 1H;
CH), 4.36-4.22 (m, 2H; ester CH2), 2.52 (s, 3H; CH3), 1.34 (t,
J = 7.2 Hz, 3H; ester CH3).
Yield: 344 mg (78%); pale yellow solid; m.p. 111–112 8C
(ethyl acetate/n-hexane).
1H NMR (300 MHz, CDCl3):
d
7.94 (d, J = 8.4 Hz, 2H; Ar–
13C NMR (75 MHz, CDCl3):
d 178.0, 172.7, 164.8, 148.4,
H), 7.30 (d, J = 8.4 Hz, 2H; Ar–H), 7.17 (d, J = 8.1 Hz, 2H; Ar–
H), 6.78 (d, J = 8.1 Hz, 2H; Ar–H), 6.07 (brs, 1H; NH), 5.64 (s,
1H; CH), 4.43 (d, J = 14.1 Hz, 1H; one H of benzylic CH2),
4.11–4.02 (m, 3H; one H of benzylic CH2 and two H of ester
CH2), 3.80 (s, 3H; OCH3), 2.31 (s, 3H; CH3), 1.18 (t, J = 7.2 Hz,
3H; ester CH3).
144.5, 141.6, 134.7, 133.1, 132.6, 129.8, 129.1, 128.5, 123.2,
121.8, 107.2, 61.3, 56.4, 17.8, 14.2.
IR (KBr, cmÀ1): 3220, 3133, 2987, 1709, 1652, 1525,
1341, 1291, 1227, 1092.
HRMS (ESI): m/z calcd for C21H19N3O5S + Na+: 448.0943
[M + Na+]; found: 448.0943.
13C NMR (75 MHz, CDCl3):
d 166.6, 159.0, 147.0, 145.7,
136.8, 129.8, 128.1, 123.5, 113.7, 59.9, 55.2, 34.1, 14.2.
IR (KBr, cmÀ1): 3304, 3082, 2985, 2934, 1652, 1512,
1475, 1344, 1268, 1247, 1158, 1105.
HRMS (ESI): m/z calcd for C22H23N3O5S + H+: 442.1437
[M + H+]; found: 442.1424.
4.2.2. Ethyl 3-cinnamoyl-6-methyl-4-(3-nitrophenyl)-2-
thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate (1.2c)
Yield: 316 mg (70%); lemon-green solid; m.p. 211–
212 8C (ethyl acetate/n-hexane).
1H NMR (300 MHz, DMSO-d6):
d 11.80 (brs, 1H; NH),
8.12–8.07 (m, 2H; Ar–H), 7.63–7.51 (m, 4H; Ar–H), 7.46–
7.33 (m, 5H; three Ar–H and two alkene H of the cinnamoyl
group), 6.25 (s, 1H; CH), 4.14–4.04 (m, 2H; ester CH2), 2.31
(s, 3H; CH3), 1.14 (t, J = 7.2 Hz, 3H; ester CH3).
4.2. Typical acylation procedure for the synthesis of ethyl 3-
acetyl-6-methyl-4-(3-nitrophenyl)-2-thioxo-1,2,3,4-
tetrahydropyrimidine-5-carboxylate (1.2a)
13C NMR (75 MHz, DMSO-d6):
d 177.1, 169.6, 164.9,
In a solution of compound 1 (321 mg, 1.0 mmol) in
anhydrous DMF (3 mL), Cs2CO3 (358 mg, 1.1 mmol) was
added. The reaction mixture was stirred at r.t. for 1 h under
anhydrous conditions. Then to the reaction mixture, DMAP
(122 mg, 1.0 mmol) and acetyl chloride (0.29 mL,
4.0 mmol) were added successively and the reaction
mixture was stirred at r.t. for 17 h under anhydrous
conditions. After completion of the reaction as indicated
by TLC, a saturated NaHCO3 solution was added. The
reaction mixture was extracted with ethyl acetate
(3 Â 35 mL). The combined organic layer was washed with
water (2 Â 50 mL), and then with the brine solution
148.3, 146.2, 142.0, 140.4, 135.0, 133.1, 130.8, 130.5, 129.3,
128.6, 123.4, 122.7, 121.3, 106.7, 60.9, 54.0, 16.9, 14.4.
IR (KBr, cmÀ1): 3209, 2983, 1709, 1654, 1618, 1532,
1351, 1228, 1158, 1093.
HRMS (ESI): m/z calcd for C23H21N3O5S + H+: 452.1280
[M + H+]; found: 452.1274.
4.2.3. Ethyl 3-acetyl-6-methyl-4-phenyl-2-thioxo-1,2,3,4-
tetrahydropyrimidine-5-carboxylate (2.2a)
Yield: 277 mg (87%); lemon-green solid; m.p. 141–
142 8C (ethyl acetate/n-hexane); lit. [10] 144–145 8C
(benzene-petroleum ether).