52 JOURNAL OF CHEMICAL RESEARCH 2010
Table 1 The overall % of yields of compounds 4a-m in both
solvent and solvent-free methods are as follows
C, 61.87; H, 3.55; N, 7.60; S, 8.69. Found: C, 61.83; H, 3.51; N, 7.54;
S, 8.64%.
3-[2-(p-Tolylamino)thiazol-4-yl]-6,8-dichloro-2H-chromen-2-one
(4d):Yellow solid, M.p. 208–209 °C. IR (KBr, νmax cm−1): 1546 (C=C),
1607 (–C=N), 1704 (lactone –C=O), 3280 (–NH). 1H NMR (DMSO-
d δ ppm): 2.28 (s, 3H, CH3), 7.19 (d, 2H, J = 6 Hz, ArH), 7.49 (d, 1H,
J6= 6 Hz, ArH), 7.63–7.66 (m, 2H, ArH), 7.78 (s, 1H, ArH), 8.15
(s, 1H, thiazole), 8.66 (s, 1H, C of coumarin), 10.25 (s, 1H, NH, D2O,
exchangeable). Anal. Calcd fo4r C H12Cl2N2O2S: C, 56.59; H, 3.00;
N, 6.95; S, 7.95. Found: C, 56.54; 1H9 , 2.96; N, 6.91; S, 7.91%.
3-[2-(p-Tolyamino)thiazol-4-yl]-6-bromo-2H-chromen-2-one (4e):
Yellow solid, M.p. 196–197 °C. IR (KBr, νmax cm−1): 1548 (C=C),
1606 (–C=N), 1732 (lactone –C=O, 3321 (–NH). 1H NMR (DMSO-d
δ ppm): 2.28 (s, 3H, CH3), 7.19 (d, 2H, J = 6 Hz, ArH), 7.43 (d, 1H6,
J = 6 Hz, ArH), 7.65 (d, 2H, J = 6 Hz, ArH), 7.76 (t, 2H, J = 6Hz,
ArH), 8.29 (s, 1H, thiazole), 8.65 (s, 1H, C of coumarin), 10.26
(s, 1H, NH, D2O, exchangeable). Anal. Calc4d for C H13BrN O2S:
C, 55.22; H, 3.17; N, 6.78; S, 7.76. Found: C, 55.18; H,139 .14; N,26.74;
S, 7.72%.
Entry
Solvent method
Solvent-free method
4a
4b
4c
4d
4e
4f
80
85
83
85
82
87
75
70
74
80
76
75
85
89
91
87
90
89
87
85
85
87
92
89
86
94
4g
4h
4i
4j
4k
4l
4m
3-[2-(p-Tolylamino)thiazol-4-yl]-6,8-dibromo-2H-chromen-2-one
(4f): Yellow solid, M.p. 220–222 °C. IR (KBr, νmax cm−1): 1550 (C=C),
1603 (–C=N), 1726 (lactone –C=O), 3319 (–NH). 1H NMR (DMSO-
d δ ppm): 2.28 (s, 3H, CH3), 7.19 (d, 2H, J = 6 Hz, ArH), 7.65 (d, 2H,
J6= 6 Hz, ArH), 7.79 (s, 1H, ArH), 8.13 (s, 1H, ArH), 8.32 (s, 1H,
thiazole), 8.61 (s, 1H, C of coumarin), 9.93 (s, 1H, NH, D2O,
exchangeable). Anal. Calc4d for C H12Br2N2O2S: C, 46.37; H, 2.46;
N, 5.69; S, 6.51. Found: C, 46.31; 1H9 , 2.42; N, 5.62; S, 6.48%.
3-[2-(Phenylamino)thiazol-4-yl]-2H-chromen-2-one (4g): Yellow
solid, M.p. 246–247 °C. IR (KBr, νmax cm−1): 1536 (C=C), 1609
General procedure for preparation of 4 from 3-(2-thiocyanatoacetyl)
coumarins
A mixture of 3-(2-thiocyanatoacetyl)coumarin (1mmol) and aryl-
amine (1mmol) was taken in 10 mL ethanol stirred at 60–65 °C for 2h.
After completion of the reaction, the product formed was filtered,
washed with ethanol and recrystallised from ethanol.
N-[4-(2-oxo-2H-chromen-3-yl)thiazol-2-yl]-N-p-tolylacetamide
(5):3-[2-(p-Tolylamino)thiazol-4-yl]-2H-chromen-2-one(4a)(1 mmol)
was taken in 3 mL of acetic anhydride and catalytic amount of
pyridine was added, the mixture was heated at 50–55 °C for 5–10 min
and kept aside for 16 h. The crude yellow crystalline solid obtained
was filtered, washed with water and recrystallised from ethanol.
1
(–C=N), 1705 (lactone –C=O), 3308 (–NH). H NMR (DMSO-d δ
ppm): 6.96 (t, 1H, J = 7 Hz, ArH), 7.30–7.38 (m, 4H, ArH), 7.556(t,
1H, J = 7 Hz, ArH), 7.66–7.73 (m, 3H, ArH), 7.75 (s, 1H, thiazole),
8.60 (s, 1H, C4 of coumarin), 9.85 (s, 1H, NH, D2O, exchangeable).
EI-MS 321 [M+ H]+. Anal. Calcd for C18H12N2O2S: C, 67.48; H, 3.78;
N, 8.74; S, 10.01. Found: C, 67.46; H, 3.71; N, 8.64; S, 9.98%.
2-[2-(Phenylamino)thiazol-4-yl]-3H-benzo[f]chromen-3-one (4h):
Yellow solid, M.p. 202–203 °C. (KBr, νmax cm−1): 1547(C=C), 1604
(–C=N), 1726 (lactone –C=O), 3310 (–NH).1H NMR (DMSO-d6
δ ppm): 7.02 (t, 1H, J = 6 Hz, ArH), 7.45 (t, 2H, J = 6 Hz, ArH),7.64–
7.70 (m, 3H, ArH), 7.78–7.80 (m, 4H, ArH), 8.11 (d, 1H, J = 6 Hz,
ArH), 8.46 (s, 1H, thiazole), 8.74 (s, 1H, C4 of coumarin), 10.44
(s, 1H, NH, D2O, exchangeable). Anal. Calcd for C H N O2S:
C, 71.33; H, 3.81; N, 7.56; S, 8.66. Found: C, 71.30; H, 3.2729;1N4 ,27.52;
S, 8.62%.
Spectral data for substituted 3-[2-(arylamino)thiazol-4-yl]coumarins
(4a–m) and its acetyl derivative 5
3-[2-(p-Tolylamino)thiazol-4-yl]-2H-chromen-2-one (4a): Yellow
solid, M.p. 184–185 °C. IR (KBr, ν
cm−1): 1538 (C=C), 1607
(–C=N), 1708 (lactone –C=O), 3307ma(x-NH). 1H NMR (DMSO-d
δ ppm): 2.27 (s, 3H, CH3), 7.13–7.17 (m, 2H, ArH), 7.29–7.35 (m, 2H6,
ArH), 7.50–7.59 (m, 3H, ArH), 7.50–7.80 (m, 2H, 1H of thiazole and
1H of ArH), 8.60 (s, 1H, C4 of coumarin), 9.85 (s, 1H, NH, D O,
exchangeable). 13C NMR (CDCl δ ppm): 20.79, 109.88, 116.227,
119.17, 119.59, 120.86, 124.48,3 128.22, 130.03, 131.21, 133.38,
137.59, 138.74, 143.97, 152.83, 159.70 and 164.63. EI-MS 335
[M+H]+. Anal. Calcd for C H14N2O S: C, 68.24; H, 4.22; N, 8.38;
S, 9.59. Found: C, 68.21; H,149 .18; N,28.40; S, 9.52%.
3-[2-(Phenylamino)thiazol-4-yl]-6-chloro-2H-chromen-2-one (4i):
Yellow solid, M.p. 168–170 °C. IR (KBr, νmax cm−1): 1546 (C=C),
1604 (–C=N), 1720 (lactone –C=O), 3358 (–NH). 1H NMR (CDCl δ
ppm): 7.10–7.14 (m, 1H, ArH), 7.40–7.43 (m, 4H, ArH), 7.59 (t, 13H,
J = 6 Hz, ArH), 7.61–7.73 (m, 2H, ArH), 7.78 (s, 1H, thiazole), 8.41
(s, 1H, C of coumarin), 8.48 (s, 1H, NH, D O, exchangeable). Anal.
Calcd for4C18H11ClN2O2S: C, 60.93; H, 3.12;2N, 7.90; S, 9.04. Found:
C, 60.90; H, 3.15; N, 7.86; S, 9.10%.
3-[2-(Phenyamino)thiazol-4-yl]-6,8-dichloro-2H-chromen-2-one
(4j):Yellow solid, M.p. 172–173 °C. IR (KBr, νmax cm−1): 1545 (C=C),
1602 (–C=N), 1720 (lactone –C=O), 3354 (–NH). 1H NMR (DMSO-
d6 δ ppm): 7.01–7.81 (m, 7H, ArH), 8.16 (s, 1H, thiazole), 8.68 (s, 1H,
C4 of coumarin), 10.37 (s, 1H, NH, D2O, exchangeable). Anal. Calcd
for C H10Cl2N O2S: C, 55.54; H, 2.59; N, 7.20; S,8.24. Found: C,
55.511;8H, 2.54;2N, 7.15; S, 8.21%.
2-[2-(p-Tolylamino)thiazol-4-yl]-3H-benzo[f]chromen-3-one (4b):
Yellow solid, M.p. 243–244 °C. IR (KBr, νmax cm−1): 1545 (C=C),
1605 (–C=N), 1708 (lactone –C=O), 3310 (–NH). 1H NMR (DMSO-
d6 δ ppm): 2.31 (s, 3H, CH3), 7.24–7.26 (m, 2H, ArH), 7.87–7.89
(m, 2H, ArH), 8.10–8.40 (m, 7H, 1H, of thiazole and 6H of ArH), 8.72
(s, 1H, C4 of coumarin), 10.33 (s, 1H, NH, D O, exchangeable).
Anal. Calcd for C23H16N2O S: C, 71.85; H, 4.192; N, 7.29; S, 8.34.
Found: C, 71.81; H, 4.16; N2, 7.25; S, 8.31%.
3-[2-(p-Tolyamino)thiazol-4-yl]-6-chloro-2H-chromen-2-one (4c):
Yellow solid, M.p. 202–203 °C. IR (KBr, νmax cm−1): 1546 (C=C),
1
1603 (–C=N), 1713 (lactone –C=O), 3320 (–NH). H NMR (CDCl
δ ppm): 2.35 (s, 3H, CH3), 7.19–7.31 (m, 6H, ArH), 7.45 (d, 1H3,
J = 6Hz, ArH) 7.55 (s, 1H, thiazole), 7.86 (s, 1H, C4 of coumarin),
8.47 (s, 1H, NH, D2O, exchangeable). Anal. Calcd for C19H13ClN2O2S:
Scheme 3 N-acetylation of compound 4a.