1008
F. Rostami-Charati et al. / Chinese Chemical Letters 23 (2012) 1007–1010
CO R
2
N
CO R
2
H O
2
+
C S
+
Ar
N
N
S
r.t., 4 h
CO R
2
CO R
2
NAr
4
3
1
2
Yield % of 4
1, 2, 4
R
Ar
a
Me
85
Phenyl
b
Me 4-nitrophenyl
Me 4-bromophenyl
94
92
c
d
e
f
Me
3-bromophenyl 92
Et
Et
Et
90
89
87
87
Phenyl
4-nitrophenyl
4-bromophenyl
3-bromophenyl
g
h
Et
Scheme 1.
were performed using a Heraeus CHN-O-Rapid analyzer. Mass spectra were recorded on a FINNIGAN-MAT 8430
spectrometer operating at an ionization potential of 70 eV. IR spectra were measured on a Shimadzu IR-460
spectrometer. 1H, and 13C NMR spectra were measured with a BRUKER DRX-500 AVANCE spectrometer at 500.1
1
and 125.8 MHz, respectively. H, and 13C, spectra were obtained for solutions in CDCl3 using TMS as internal
standard or 85% H3PO4 as external standard.
2.1. General procedure for preparation of compounds 4a–h and 8a–d
To a magnetically stirred solution of arylisothiocyanate 1 and dialkyl acetylenedicarboxylates 2 (2 mmol) in water
was added isoquinoline 3 or quinoline 7 (2 mmol) slowly and the reaction mixture stirred for 4 h at room temperature.
After completion of the reaction as indicated by TLC (ethyl acetate/n-hexane), the reaction mixture was purified by
column chromatography to afford pure title compounds.
2.1.1. Dimethyl 2-(phenylimino)-2H,11bH-[1,3]thiazino-[2,3-a]isoquinoline-3,4-dicarboxylate (4a)
Yellow powder, mp 135–137 8C, yield 85%, IR (KBr) (nmax/cmÀ1): 1725, 1720, 1685, 1587, 1432 and 1129. 1H
NMR: d 3.65 (s, 3 H, MeO), 3.82 (s, 3 H, MeO), 7.25 (s, 1 H, CH), 7.54 (d, 1 H, 3J = 7.6 Hz, CH), 7.53 (t, 2 H, 3J = 7.2,
3
3
3
2 CH), 7.61 (t, 1 H, J = 7.2, CH), 7.69 (t, 1 H, J = 7.2 Hz, CH), 7.73 (t, 1 H, J = 7.2 Hz, CH), 7.93 (d, 1 H,
3
3J = 7.5 Hz, CH), 8.02 (d, 2 H, J = 7.3, 2 CH), 8.69 (d, 1 H, J = 7.5 Hz, CH), 9.31 (d, 1 H, J = 7.6 Hz, CH). 13
C
3
3
NMR: d 52.5 (MeO), 53.0 (MeO), 65.2 (CH), 103.4 (CH), 112.4 (C), 120.3 (2 CH), 122.3 (CH), 123.6 (CH), 125.4
(CH), 125.7 (CH), 128.7 (2 CH), 129.0 (CH), 138.2 (C), 133.5 (C), 139.7 (C), 140.1 (C), 148.7 (C–N), 157.4 (C N),
160.7 (C O), 161.5 (C O). Anal. Calcd. for C22H18N2O4S (406.45): C, 65.01; H, 4.46; N, 6.89 found: C, 64.95; H,
4.38; N, 6.75.
2.1.2. Dimethyl 2-(4-nitrophenylimino)-2H,11bH-[1,3]thiazino-[2,3-a]isoquinoline-3,4-dicarboxylate (4b)
Pale yellow crystals, mp 153–155 8C, yield 94%. IR (KBr) (nmax/cmÀ1): 1745, 1732, 1658, 1587, 1489, 1365, 1258
and 1157. 1H NMR: d 3.81 (s, 3 H, MeO), 3.92 (s, 3 H, MeO), 6.98 (d, 2 H, 3J = 7.6, 2 CH), 7.28 (s, 1 H, CH), 7.49 (d, 1
H, 3J = 7.6 Hz, CH), 7.65 (t, 1 H, 3J = 7.3 Hz, CH), 7.68 (t, 1 H, 3J = 7.3 Hz, CH), 7.88 (d, 1 H, 3J = 7.5 Hz, CH), 8.28
(d, 2 H, 3J = 7.5, 2 CH), 8.65 (d, 1 H, 3J = 7.5 Hz, CH), 9.27 (d, 1 H, 3J = 7.6 Hz, CH). 13C NMR: d 53.2 (MeO), 53.8
(MeO), 65.4 (CH), 103.8 (CH), 111.4 (C), 120.0 (2 CH), 123.5 (CH), 126.1 (2 CH), 127.2 (CH), 127.8 (CH), 128.5
(CH), 130.8 (CH), 139.6 (C), 141.6 (C), 146.8 (C), 154.2 (C), 154.9 (C–N), 156.2 (C N), 160.7 (C O), 166.5 (C O).
Anal. Calcd. for C22H17N3O6S (451.45): C, 58.53; H, 3.80; N, 9.31 found: C, 58.48; H, 3.75; N, 9.28.
2.1.3. Dimethyl 2-(4-bromophenylimino)-2H,11bH-[1,3]thiazino-[2,3-a]isoquinoline-3,4-dicarboxylate (4c)
Orange crystals, mp 165–167 8C, yield 92%. IR (KBr) (nmax/cmÀ1): 1725, 1715, 1658, 1424. 1310, 1258 and 1100.
1H NMR: d 3.81 (s, 3 H, MeO), 3.91 (s, 3 H, MeO), 6.76 (d, 2 H, 3J = 7.8, 2 CH), 7.19 (d, 1 H, 3J = 7.7 Hz, CH), 7.32 (s,
1 H, CH), 7.51 (d, 2 H, 3J = 8.0, 2 CH), 7.54 (t, 1 H, 3J = 7.4 Hz, CH), 7.59 (t, 1 H, 3J = 7.4 Hz, CH), 7.70 (d, 1 H,
3J = 7.5 Hz, CH), 8.44 (d, 1 H, 3J = 7.5 Hz, CH), 9.23 (d, 1 H, 3J = 7.7 Hz, CH). 13C NMR: d 52.6 (MeO), 53.2 (MeO),