984
A. Dandia et al.
ꢀm = 3,350, 2,935, 1,690, 1,620, 1,580, 1,490, 745 cm-1 ; 1H
NMR (300 MHz, CDCl3): d = 1.10 (3H, s, CH3), 1.33
(3H, s, CH3), 1.59 (1H, s, 2,4-HA), 1.75 (1H, s, 2,4-HA),
2.38 (1H, s, 2,4-HB), 2.62 (1H, s, 2,4-HB), 5.48 (1H, s,
CH), 6.98–7.69 (3H, m, Ar–H), 12.69 (1H, bs, NH,
D2O exchangeable) ppm; 13C NMR (75 MHz, CDCl3):
d = 28.65, 40.23, 43.56, 103.23, 108.20, 124.80, 128.60,
135.40, 152.32, 154.80 ppm; DIPMS: m/z = 306.05 (M)?,
307.05 (M ? 1)?; HRMS (EI): calcd. 306.0594, found
306.0601.
(1H, s, 2,4-HA), 1.75 (1H, s, 2,4-HA), 2.32 (1H, s, 2,4-HB),
2.50 (1H, s, 2,4-HB), 4.69 (1H, s, CH), 7.15-8.05 (7H, m,
Ar- H) ppm; 13C NMR (75 MHz, CDCl3): d = 17.90,
28.21, 29.81, 45.63, 47.55, 50.02, 119.04, 121.80, 125.60,
129.40, 130.90, 134.80, 139.40, 144.80, 147.90, 164.00,
192.50 ppm; DIPMS: m/z = 439.07 (M)?, 440.07
(M ? 1)?; HRMS (EI): calcd. 439.0757, found 439.0789.
8-Chloro-2,3,4,12-tetrahydro-3,3-dimethyl-12-(3-nitro-
phenyl)-1H-benzothiazolo[2,3-b]quinazolin-1-one
(4c, C22H18ClN3O3S)
ꢀ
9-(4-Chlorophenyl)-3,4,5,6,7,9-hexahydro-3,3,6,6-
tetramethyl-1H-xanthene-1,8(2H)-dione (8)
M.p.: 127 °C; IR (KBr): m = 2,936–2,876, 1,678, 1,620,
1,560, 1,520, 1,370, 760 cm-1 1H NMR (300 MHz,
;
A mixture of 2 (0.01 mol) and 3 (0.02 mol) in the
minimum quantity of ethanol was irradiated under micro-
waves (300 W) intermittently until completion of the
reaction (5 min, TLC), and after cooling pure product 8
was obtained. M.p.: 231 °C (Refs. [43] 228–230 °C, [44]
230–232 °C (EtOH)).
CDCl3): d = 1.08 (3H, s, CH3), 1.28 (3H, s, CH3), 1.62
(1H, s, 2,4-HA), 1.78 (1H, s, 2,4-HA), 2.33 (1H, s, 2,4-HB),
2.56 (1H, s, 2,4-HB), 4.69 (1H, s, CH), 7.15–8.10 (7H, m,
ArH) ppm; 13C NMR (75 MHz, CDCl3): d = 17.86, 28.41,
29.93, 45.79, 47.91, 50.22, 120.01, 124.70, 128.90, 132.40,
133.80, 138.60, 143.50, 148.90, 163.01, 190.85 ppm;
DIPMS: m/z = 439.07 (M)?, 440.07 (M ? 1)?; HRMS
(EI): calcd. 439.0757, found 439.0790.
Synthesis of 4a from the intermediates
8-Chloro-2,3,4,12-tetrahydro-3,3-dimethyl-12-phenyl-
1H-benzothiazolo[2,3-b]quinazolin-1-one
(4d, C22H19ClN2OS)
Equimolar mixtures of intermediates 6a, 7, and 8 with 1,
2a, and 1, respectively (Table 1) in the minimum quantity
of ethanol required to form a slurry were irradiated in the
microwave oven for an appropriate time (monitored by
TLC, Table 1). Crystals of 4a separated on cooling in
every case.
ꢀ
M.p.: 187 °C; IR (KBr): m = 2,928–2,879, 1,678, 1,630,
1,540, 1,480, 750 cm-1 1H NMR (300 MHz, CDCl3):
;
d = 1.05 (3H, s, CH3), 1.22 (3H, s, CH3), 1.58 (1H, s, 2,4-
HA), 1.72 (1H, s, 2,4-HA), 2.29 (1H, s, 2,4-HB), 2.43 (1H, s,
2,4-HB), 4.66 (1H, s, CH), 6.97–7.28 (8H, m, Ar–H) ppm;
13C NMR (75 MHz, CDCl3): d = 17.68, 28.52, 29.89,
45.92, 47.84, 50.18, 121.02, 122.30, 124.60, 130.70,
132.60, 138.70, 140.50, 143.90, 149.40, 162.04,
190.02 ppm; DIPMS: m/z = 394.09 (M)?, 395.09
(M ? 1)?; HRMS (EI): calcd. 394.0907, found 394.1009 .
The same reactions were also performed using DMF
instead of ethanol under microwaves. Isolation of product
in a manner similar to that after the multicomponent
reaction gave identical product in all cases.
8-Chloro-12-(4-chlorophenyl)-2,3,4,12-tetrahydro-3,3-
dimethyl-1H-benzothiazolo[2,3-b]quinazolin-1-one
(4a, C22H18Cl2N2OS)
8-Chloro-12-(2-chlorophenyl)-2,3,4,12-tetrahydro-3,3-
dimethyl-1H-benzothiazolo[2,3-b]quinazolin-1-one
(4e, C22H18Cl2N2OS)
ꢀ
M.p.: 192 °C; IR (KBr): m = 2,930–2,875, 1,680, 1,625,
1,580, 1,485, 765 cm-1 1H NMR (300 MHz, CDCl3):
;
M.p.: 226 °C; IR (KBr): m =2,930– 2,880, 1,685, 1,625,
ꢀ
d = 1.03 (3H, s, CH3), 1.23 (3H, s, CH3), 1.57 (1H, s,
2,4-HA), 1.78 (1H, s, 2,4-HA), 2.28 (1H, s, 2,4-HB), 2.42 (1H,
s, 2,4-HB), 4.68 (1H, s, CH), 6.98–7.28 (7H, m, Ar–H) ppm;
13C NMR (75 MHz, CDCl3): d = 17.10, 27.82, 29.21,
45.24, 47.38, 50.08, 116.02, 120.60, 124.30, 128.60, 131.50,
135.80, 138.60, 141.30, 148.50, 158.20, 159.60, 162.09,
191.22 ppm; DIPMS: m/z = 428.05 (M)?, 429.02
(M ? 1)?; HRMS (EI): calcd. 428.0517, found 428.0524.
1,560, 1,490, 740 cm-1
;
1H NMR (300 MHz, CDCl3):
d = 1.08 (3H, s, CH3), 1.23 (3H, s, CH3), 1.56 (1H, s, 2,4-
HA), 1.78 (1H, s, 2,4-HA), 2.30 (1H, s, 2,4-HB), 2.53 (1H, s,
2,4-HB), 4.69 (1H, s, CH), 6.89–7.21 (7H, m, Ar–H) ppm;
13C NMR (75 MHz, CDCl3): d = 17.45, 28.51, 29.79,
45.3, 47.59, 50.19, 122.03, 125.60, 128.70, 131.70, 133.40,
139.20, 142.30, 143.80, 149.60, 167.03, 192.30 ppm;
DIPMS: m/z = 428.05 (M)?, 429.05 (M ? 1)?; HRMS
(EI): calcd. 428.0517, found 429.0530.
8-Chloro-2,3,4,12-tetrahydro-3,3-dimethyl-12-(2-nitro-
phenyl)-1H-benzothiazolo[2,3-b]quinazolin-1-one
(4b, C22H18ClN3O3S)
8-Chloro-2,3,4,12-tetrahydro-12-(4-methoxyphenyl)-
3,3-dimethyl-1H-benzothiazolo[2,3-b]quinazolin-1-one
(4f, C22H18Cl2N2OS)
ꢀ
M.p.: 172 °C; IR (KBr): m = 2,935– 2,885, 1,675, 1,615,
1,570, 1,510, 1,360, 740 cm-1 1H NMR (300 MHz,
;
M.p.: 207 °C; IR (KBr): m = 2,928– 2,878, 1,680, 1,632,
ꢀ
CDCl3): d = 1.09 (3H, s, CH3), 1.27 (3H, s, CH3), 1.61
1,530, 1,480, 1,130, 760 cm-1
;
1H NMR (300 MHz,
123