ꢁꢁꢁꢂ
ꢀR. Gupta and R.P. Chaudhary: Fused thiazolopyrimidine derivatives
212ꢀ
3-(4-Methoxyphenyl)-1-phenylprop-2-en-1-one (3b)ꢀThis com- white solid; mp 100–102°C; IR: υ 1744 (C=O), 1612 (C=N) cm-1; 1H NMR:
pound was obtained in 92% yield as a yellow solid; mp 72–74°C (Lit. δ 3.84 (s, 3H, OCH3), 4.62 (dd, 2H, SCH2, J = 5.7 Hz, J = 7.4 Hz), 6.95 (s,
mp 69–71°C); IR: υ 1658 (C=O) cm-1; 1H NMR: δ 3.85 (s, 3H, OCH3), 6.93 1H, HA), 6.97 (s, 1H, CH), 7.52 (t, 2H, Ar-H, J = 7.4 Hz), 7.60 (m, 2H, Ar-
(m, 2H, Ar-H), 7.41 (d, 1H, CH, J = 15.6 Hz), 7.49 (m, 2H, Ar-H), 7.55 H), 7.72 (m, 3H, Ar-H), 8.05 (m, 2H, Ar-H); 13C NMR: δ 170, 159, 155, 139,
(m, 1H, Ar-H), 7.59 (m, 2H, Ar-H), 7.79 (d, 1H, CH, J = 15.6 Hz), 8.01 134, 131, 129, 127, 126, 121, 113, 111, 54, 40, 39, 38, 31, 28, 27; MS: m/z 337
(m, 2H, Ar-H). Anal. Calcd for C16H14O2: C, 80.67; H, 5.88. Found: C, (M+H+, 70%). Anal. Calcd for C19H16N2SO2: C, 67.86; H, 4.76; N, 8.33; S,
80.58; H, 5.94.
9.52. Found: C, 67.76; H, 4.85; N, 8.27; S, 9.59.
General procedure for synthesis of
compounds 4
General procedure for synthesis of
compounds 6
Compound 3 (0.005 mol), and thiourea (0.38 g, 0.005 mol) in etha- A mixture of thione 4 (0.01 mol) and 1,2-dibromoethane (5.0 mL) was
nolic KOH (1 g in 20 mL ethanol) was heated under reflux for 4 h. The stirred at 110°C for 4 h. The crude solid 6 was purified by silica gel
mixture was concentrated to half, and the concentrate was poured column chromatography using petroleum ether/ethyl acetate (4:1) as
into ice-cold water. The resultant solid of 4 was filtered, washed with an eluent.
water and crystallized from ethanol [24].
5,7-Diphenyl-3,5-dihydro-2H-thiazolo[3,2-a]pyrimidine (6a)ꢀThis
4,6-Diphenyl-3,4-dihydropyrimidine-2(1H)-thione (4a)ꢀThis com- compound was obtained in 65% yield as a brown solid; mp 140–142°C;
pound was obtained in 82% yield as a yellow solid; mp 160–162°C; IR: IR: υ 1673 (C=N) cm-1; 1H NMR: δ 2.42 (t, 2H, SCH2, J = 7.8 Hz), 3.52 (t, 2H,
υ 1180 (C=S), 1558 (C=C), 3171 (NH) cm-1; 1H NMR: δ 5.12 (m, 1H, HA), 5.31 NCH2, J = 7.9 Hz), 5.32 (s, 1H, HA), 5.64 (s, 1H, CH), 7.20 (m, 10H, C6H5); 13C
(m, 1H, CH), 7.28 (m, 1H, Ar-H), 7.37 (m, 7H, Ar-H), 7.47 (m, 2H, Ar-H), NMR: δ 165, 138, 131, 129, 128, 127, 125, 103, 59, 52, 40, 39, 38, 31, 30, 28,
9.08 (br, 1H, NH, exchangeable with D2O), 9.77 (br, 1H, NH, exchange- 22, 13; MS: m/z 293 (M+H+, 100%). Anal. Calcd for C18H16N2S: C, 73.97; H,
able with D2O). Anal. Calcd for C16H14N2S: C, 72.18; H, 5.26; N, 10.53; S, 5.48; N, 9.59; S, 10.96. Found: C, 73.88; H, 5.54; N, 9.50; S, 10.88.
12.03. Found: C, 72.10; H, 5.34; N, 10.45; S, 12.12.
5-(4-Methoxyphenyl)-7-phenyl-3,5-dihydro-2H-thiazolo[3,2-a]
4-(4-Methoxyphenyl)-6-phenyl-3,4-dihydropyrimidine-2(1H)- pyrimidine (6b)ꢀThis compound was obtained in 62% yield as a
thione (4b)ꢀThis compound was obtained in 86% yield as a yellow yellow solid; mp 160–162°C; IR: υ 1672 (C=N) cm-1; 1H NMR:δ 2.84–2.87
solid; mp 176–178°C; IR: υ 1250 (C=S), 1558 (C=C), 3202 (NH) cm-1; 1H (t, 2H, SCH2, J = 6 Hz), 2.95–2.98 (t, 2H, NCH2, J = 6 Hz), 3.79 (s, 3H,
NMR: δ 3.78 (s, 3H, OCH3), 5.13 (m, 1H, HA), 5.19 (m, 1H, CH), 6.88 (m, OCH3), 5.72 (d, 1H, HA, J = 10 Hz), 5.75–5.77 (d, 1H, CH, J = 8 Hz), 6.84–
2H, Ar-H), 7.28 (m, 2H, Ar-H), 7.36 (m, 3H, Ar-H), 7.49 (m, 2H, Ar-H), 6.87 (m, 2H, Ar-H), 6.91 (d, 2H, Ar-H, J= 4 Hz), 7.10–7.14 (m, 1H, Ar-H),
8.75 (br, 1H, NH, exchanged with D2O), 9.05 (br, 1H, NH, exchange- 7.25–7.27 (d, 1H, Ar-H, J = 7 Hz), 7.47 (m, 3H, Ar-H); 13C NMR: δ 165, 160,
able with D2O). Anal. Calcd for C17H16N2SO: C, 68.92; H, 5.41; N, 9.46; S, 132, 131, 130, 129, 128, 126, 125, 114, 103, 59, 55, 52, 40, 39, 31, 30, 27, 22,
10.81. Found: C, 68.87; H, 5.49; N, 9.54; S, 10.92.
14; MS: m/z 323 (M+H+, 100%). Anal. Calcd for C19H18N2SO: C, 70.81; H,
5.59; N, 8.70; S, 9.94. Found: C, 70.92; H, 5.67; N, 8.81; S, 9.88.
General procedure for synthesis of thiazoli-
dinones 5
A mixture of compound 4 (0.01 mol), chloroacetic acid (0.94 g, 0.01
mol) and anhydrous sodium acetate (0.82 g, 0.01 mol) in absolute eth-
anol (20 mL) was heated under reflux for 5 h. The mixture was cooled
to room temperature and then poured into water. The resultant solid
of 5 was filtered, washed with water and crystallized from ethanol.
General procedure for synthesis of arylidene
derivatives (7)
These compounds were prepared by two routes. (i) A mixture of thia-
zolidinone 5 (0.001 mol), aromatic aldehyde (0.001 mol) and anhy-
drous sodium acetate (0.082 g, 0.001 mol) in glacial acetic acid (10
mL) was heated under reflux for 4 h. The mixture was cooled to room
temperature and poured into water. The solid thus obtained was fil-
tered and washed with water and crystallized from dimethylforma-
mide and ethanol mixture (1:1) to give compound 7. (ii) A mixture
of thione 4a (0.001 mol), chloroacetic acid (0.094 g, 0.001 mol) and
aromatic aldehyde (0.001 mol) and anhydrous sodium acetate (0.082
g, 0.001 mol) in glacial acetic acid (10 mL) and acetic anhydride (1
mL) was heated under reflux for 3–4 h. A similar work up as in (i)
gave compound 7a.
5,7-Diphenyl-2H-thiazolo[3,2-a]pyrimidin-3(5H)-one (5a)ꢀThis
compound was obtained in 78% yield as a shining white solid; mp
1
80–84°C; IR: υ 1744 (C=O), 1651 (C=N) cm-1; H NMR: δ 3.90–4.01
(dd, 2H, SCH2, J = 12.6, J = 17.2 Hz), 5.59 (s, 1H, HA), 5.86 (s, 1H, CH),
7.12 (m, 1H, Ar-H); 7.22 (m, 1H, Ar-H); 7.28 (m, 2H, Ar-H); 7.35 (m, 5H,
Ar-H); 7.82 (d, 1H, Ar-H, J = 7.5 Hz); 13C NMR: δ 189, 161, 144, 137, 132,
130, 128, 127, 119, 114, 55, 40, 39; MS: m/z 307 (M+H+, 63%). Anal.
Calcd for C18H14N2SO: C, 70.59; H, 4.58; N, 9.15; S, 10.46. Found: C,
70.65; H, 4.65; N, 9.24; S, 10.52.
(E)-2-Benzylidene-5,7-diphenyl-2H-thiazolo[3,2-a]pyrimidin-
3(5H)-one (7a)ꢀThis compound was obtained in 70% yield as a
shining yellow solid; mp 212–214°C; IR: υ 1728 (C=O), 1582 (C=N) cm-1;
1H NMR: δ 6.28 (s, 1H, HA), 6.72 (s, 1H, CH), 7.47 (m, 4H, Ar-H), 7.55 (m,
5-(4-Methoxyphenyl)-7-phenyl-2H-thiazolo[3,2-a]pyrimidin-
3(5H)-one (5b)ꢀThis compound was obtained in 80% yield as a
Brought to you by | Massachusetts Institute of Technology - MIT Libraries
Authenticated | 18.7.29.240
Download Date | 6/12/13 3:24 PM