8
M. S. SALEM ET AL.
3.1.1. General procedure
A mixture of benzothiazinethione 1 (2.5 mmol, 1 g) and substituted amines namely 4-
hydroxy aniline, 4-aminopyridine, o-toluidine, and /or benzyl amine (0.01 mmol) in
ethanol (20 ml) was heated at reflux temperature for 5–10 h, left to cool the solid prod-
uct was collected, dried and recrystallized to afford 2-phenylquinazolinthione 3 and
benzamide derivatives 4–6.
3-(4-Hydroxyphenyl)-6-iodo-2-phenylquinazoline-4(3H)-thione (3) recrystallized from
methanol (red crystals), mp 275–279°C, yield 55%. FT-IR (KBr, cm−1): 3425 ν
3056
OH,
1
ν
aromatic, 1223 νC=S. H NMR (400 MHz, DMSO-d6): 9.58 (s, 1H, OH, D2O
CH
exchangeable), 8.20-8.13, 7.56-7.51 (2 m, 2H, Ar-H), 7.36-7.33 (m, 2H, Ar-H), 7.25-
7.19 (m, 4H, Ar-H),7.04, 6.60 (2 d, 4H, phenol moiety, J = 8 Hz). 13C NMR (100 MHz,
DMSO–d6) δ (ppm): 188.63, 157.38, 156.11, 143.61, 142.14, 139.18, 136.44, 135.26, 133.82,
•
130.68, 130.53,129.25, 129.15, 127.80, 115.71 and 94.66. MS (m/z (%)): 456 (M+, 100.00),
330 (74.81), 204 (60.08), 105 (50.83), 77 (46.71), 65 (21.26). Anal. Calcd for C20H13IN2OS
(456.30): C, 52.65; H, 2.87; N, 6.14; S, 7.03. Found: C, 52.51; H, 2.70; N, 5.97; S, 6.98.
N-(4-Iodo-2-(pyridin-4-ylcarbamothioyl)phenyl)benzamide (4) recrystallized from
ethanol (red crystals), mp 150–152°C, yield 43%. FT-IR (KBr, cm−1): 3384, 3183 ν
,
NH
1670 ν
amide, 1199 ν
1H NMR (400 MHz, DMSO-d6): 8.25 (d, 2H, pyridine-H,
C=O
C=S.
J = 8 Hz), 8.21-8.05 (m, 3H, Ar-H), 8.00 (s, 1H, NHCO, D2O exchangeable), 7.68-7.96 (m,
5H, Ar-H), 7.06 (s, 1H, NHCS, D2O exchangeable), 6.61 (d, 2H, pyridine-H, J = 4 Hz).
13C NMR (100 MHz, DMSO–d6) δ (ppm): 208.85, 157.72, 145.48, 144.60, 135.20, 134.12,
133.82, 133.43, 129.92, 129.01,127.86, 127.56, 127.25, 109.21 and 97.33. MS (m/z (%)): 460
•
([M+1]+, 3.69), 406 (30.65), 301 (57.69), 238 (83.59), 226 (78.34), 143 (26.18), 58 (83.11),
44 (100.00). Anal. Calcd for C19H14IN3OS (459.31): C, 49.69; H, 3.07; N, 9.15; S, 6.98.
Found: C, 49.75; H, 2.94; N, 8.97; S, 6.76.
2-Benzamido-5-iodo-N-(o-tolyl)benzamide (5) recrystallized from dioxane (red crys-
tals), mp 144–146°C, yield 60%. FT-IR (KBr, cm−1): 3284, 3250 νNH, 3062 νCH aromatic,
1
2955ν
aliphatic, 1652 νC=O. H NMR (400 MHz, DMSO-d6): 11.69, 10.52 (2s, 2H,
CH
2NHCO, D2O exchangeable), 8.30-7.15 (m, 12H, Ar-H), 2.27 (s, 3H, CH3). 13C NMR
(100 MHz, DMSO–d6) δ (ppm): 166.23, 165.01, 140.99, 138.85, 137.29, 136.10, 134.68,
134.01, 132.61, 129.50,129.38, 127.46, 125.13, 123.66, 121.75, 87.51 and 20.98.MS (m/z
•
(%)): 456 (M+, 1.26), 438 (1.10), 349 (6.35), 254 (22.95), 211 (4.09), 127 (3.19), 106
(100.00), 77 (26.99). Anal. Calcd for C21H17IN2O2 (456.28): C, 55.28; H, 3.76; N, 6.14.
Found: C, 55.12; H, 3.63; N, 6.01.
N-(2-(Benzylcarbamothioyl)-4-iodophenyl)benzamide (6) recrystallized from light
petroleum ether (80–100°C) (yellow crystals), mp 108–109°C, yield 65%. FT-IR (KBr,
cm−1): 3305, 3256 ν
3060 ν aromatic, 2949 ν aliphatic, 1679 ν
amide, 1232
NH,
CH
CH
C=O
ν
1H NMR (400 MHz, DMSO-d6): 11.48 (s, 1H, CONH-, D2O exchangeable), 8.35 (s,
C=S.
1H, CH2NH-, D2O exchangeable), 8.33-6.86 (m, 13H, Ar-H), 3.87 (s, 2H, CH2). 13C NMR
(100 MHz, DMSO–d6) δ (ppm): 187.06, 167.17, 142.93, 138.85, 140.19, 139.02, 134.53,
132.82, 129.45, 128.78,128.61, 128.28, 127.55, 126.45, 123.42, 119.85, 87.43 and 53.35. MS
•
(m/z (%)): 471 ([M-1]+, 1.42), 452 (22.57), 363 (20.17), 299 (34.55), 149 (100.00). Anal.
Calcd for C21H17IN2OS (472.34): C, 53.40; H, 3.63; N, 5.93; S, 6.79. Found: C, 53.31; H,
3.47; N, 5.78; S, 6.62.