BRITSUN et al.
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3000–3300, 3400. H NMR spectrum, δ, ppm (J, Hz):
6.22 d (1H, H2, J 14.1), 7.33–7.45 m (10H, 2Ph), 7.65 d
(1H, H3, J 14.1), 9.78 s (1H, NH), 10.12 s (1H, NH).
Found, %: C 67.78; H 4.72; N 10.11. C16H14N2OS. Cal-
culated, %: C 68.06; H 5.00; N 9.92.
and 1,3-thiazin-4-one Va was filtered off. Yield 0.243 g
(86%), mp188–190°C. The mixed sample of compound
Va thus obtained and that prepared by reaction of N-phe-
nylthiourea with 3-phenyl-2-propenoyl chloride in acetone
in the presence of K2CO3 melted without depression of
the melting point.
N-[3-(2-Thienyl)-2-propenoyl]-N-phenylthiourea
(IVb). Yield 0.807 g (28%), mp 142–144°C. IR spec-
trum, cm–1: 1270, 1320, 1410, 1500, 1590, 1670, 3000–
3300. 1H NMR spectrum, δ, ppm (J, Hz): 5.90 d (1H, H2,
J 14.4), 7.04 d.d (1H,Ar, J1 5.3, J2 3.0), 7.28–7.57 m (7H,
Ar), 7.76 d (1H, H3, J 14.4), 9.75 s (1H, NH), 10.15 s
(1H, NH). Found, %: C 58.57; H 3.98; N 9.48.
C14H12N2OS2. Calculated, %: C 58.31; H 4.19; N 9.71.
6-Aryl-3-phenyl-2-phenylimino-2,3,5,6-tetrahy-
dro-4H-1,3-thiazin-4-ones VIIa–VIIe. To a solution
of 2.28 g (0.01 mol) of N,N'-diphenylthiourea (VI) in
15 ml of anhydrous acetone at 20°C while stirring was
added a solution of 0.01 mol of 3-aryl-2-propenoyl chlo-
ride IIa–IIe in 10 ml of acetone. The mixture was stirred
for 10 min at 20°C and 30 min at 56°C, then it was cooled,
the reaction product VIIa–VIIe was filtered off, dried in
a drying cabinet at 100°C, and recrystallized from
CH3COOH.
3,6-Diphenyl-2-imino-2,3,5,6-tetrahydro-4H-1,3-
thiazin-4-one (Va). Yield 1.18 g (42%), mp 190–192°C.
IR spectrum, cm–1: 1360, 1410, 1460, 1500, 1580, 1695,
3100, 3300. 1H NMR spectrum, δ, ppm (J, Hz): 3.18 m
(1H, H5), 3.49 m (1H, H5), 5.02 m (1H, H6), 7.15 m (2H,
Ar), 7.31–7.50 m (8H,Ar), 8.84 br.s (1H, NH). 13C NMR
spectrum, δ, ppm: 39.8 (C6), 41.6 (C5), 127.4, 127.6, 128.2,
128.8, 129.0, 129.2, 138.0 (Ar), 155.9 (C2), 169.3 (C4).
Found, %: C 67.85; H 5.26; N 10.13. C16H14N2OS. Cal-
culated, %: C 68.06; H 5.00; N 9.92.
3,6-Diphenyl-2-phenylimino-2,3,5,6-tetrahydro-4H-1,3-
thiazin-4-one (VIIa).Yield 2.51 g (70%), mp 200–201°C.
IR spectrum, cm–1: 1210, 1260, 1350, 1480, 1610, 1685,
3000–3100. 1H NMR spectrum, δ, ppm: 3.20 m (1H, H5),
3.57 m (1H, H5), 5.01 m (1H, H6), 6.66 m (2H Ar), 6.98 m
13
(1H, Ar), 7.16–7.55 m (12HAr). C NMR spectrum, δ,
ppm: 39.8 (C6), 41.6 (C5), 120.2, 123.7, 127.5, 128.4,
128.8, 128.9, 129.1, 137.5, 138.8, 147.8 (Ar), 152.4 (C2),
169.2 (C4). Found, %: C 73.44; H 4.83; N 8.09.
C22H18N2OS. Calculated, %: C 73.72; H 5.06; N 7.82.
6-Thienyl-3-phenyl-2-imino-2,3,5,6-tetrahydro-4H-1,3-
thiazin-4-one (Vb). Yield 1.12 g (39%), mp 137–140°C.
IR spectrum, cm–1: 1280, 1360, 1510, 1570, 1695, 3000,
3100, 3300. 1H NMR spectrum, δ, ppm: 3.39 m (2H, H5),
5.23 m (1H, H6), 7.06–7.14 m (4H, Ar), 7.25–7.56 m
(4H, Ar), 9.08 br.s (1H, NH). Found, %: C 58.36; H 4.03;
N 9.44. C14H12N2OS2. Calculated, %: C 58.31; H 4.19;
N 9.71.
6-Thienyl-3-phenyl-2-phenylimino-2,3,5,6-tetrahydro-
4H-1,3-thiazin-4-one (VIIb).Yield 2.37 g (65%), mp 202–
204°C. IR spectrum, cm–1: 1210, 1260, 1320, 1340, 1485,
1590, 1680, 3100. 1H NMR spectrum, δ, ppm : 3.45 m
(2H, H5), 5.29 m (1H, H6), 6.67 m (2HAr), 7.01–7.50 m
(11HAr). Found, %: C 66.14; H 4.30; N 7.42.
C20H16N2OS2. Calculated, %: C 65.91; H 4.42; N 7.69.
Cyclization of N-(3-phenyl-2-propenoyl)-N-phe-
nyl-thiourea (IVa) into 3,6-diphenyl-2-imino-2,3,5,6-
tetrahydro-4H-1,3-thiazin-4-one hydrochloride
(IIIa). Through a solution of 0.282 g (0.001 mol) of
N-phenylthiourea IVa in 3 ml of dry acetone at 50°C was
passed for 10 min a flow of dry HCl. The reaction mix-
ture was cooled, and precipitated hydrochloride IIIa was
filtered off. Yield 0.255 g (80%), mp 208–210°C. The
mixed sample of compound IIIa thus obtained and that
prepared by reaction of N-phenylthiourea with 3-phenyl-
2-propenoyl chloride in acetone melted without depres-
sion of the melting point.
6-(4-Methoxyphenyl)-3-phenyl-2-phenylimino-2,3,5,6-
tetrahydro-4H-1,3-thiazin-4-one (VIIc). Yield 2.87 g
(74%), mp 246–248°C. IR spectrum, cm–1: 1210, 1260,
1330, 1480, 1510, 1595, 1680, 3000. 1H NMR spectrum,
δ, ppm: 3.15 m (1H, H5), 3.55 m (1H, H5), 3.81 s (3H,
CH3O), 4.94 m (1H, H6), 6.65 m (2H Ar), 6.91 d (2H,
ï -C6H4, J 8.7 Hz), 6.97 m (1H, Ar), 7.24 m (4HAr),
7.34 d (2H, ï -C6H4, J 8.7 Hz), 7.47 m (3HAr). Found, %:
C 70.92; H 5.42; N 6.92. C23H20N2O2S. Calculated, %:
C 71.11; H 5.19; N 7.21.
6-(4-Fluorophenyl)-3-phenyl-2-phenylimino-2,3,5,6-
tetrahydro-4H-1,3-thiazin-4-one (VIId). Yield 2.56 g
(68%), mp 213–215°C. IR spectrum, cm–1: 1210, 1230,
1270, 1350, 1510, 1605, 1695, 3100. 1H NMR spectrum,
δ, ppm: 3.20 m (1H, H5), 3.57 m (1H, H5), 5.04 m (1H,
Preparation of base Va from 3,6-diphenyl-2-
imino-2,3,5,6-tetrahydro-4H-1,3-thiazin-4-one hy-
drochloride (IIIa). A mixture of 0.319 g (0.001 mol) of
hydrochloride Va with a solution of 0.002 mol of K2CO3
in 5 ml of water was stirred for 20 min at 50°C, cooled,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 42 No. 11 2006