10016
L. D. S. Yadav et al. / Tetrahedron 61 (2005) 10013–10017
1
3
C NMR (DMSO-d /TMS) d: 26.1 (5-C), 42.7 (6-C), 54.7
6
C H ClNO S : C, 51.57; H, 3.56; N, 3.54%. Found: C,
17 14 2 3
(
1
(
OMe), 127.2, 128.5, 129.4, 130.3, 131.2, 132.4, 133.3,
34.4 (Ph, 4-MeOC H ), 165.4 (C]O), 192.2 (C]S). Mass
m/z): 361 (M ). Anal. Calcd for C H NO S : C, 56.48;
51.21; H, 3.77; N, 3.35%.
6
4
C
1
7
15
2 3
4.2.9. Compound 4i. Yellowish needles (3.05 g, 78%), mp
155–156 8C. IR (KBr) n
H, 4.18; N, 3.87%. Found: C, 56.14; H, 4.38; N, 3.65%.
3013, 2592, 1685, 1603, 1586,
max
K1
458, 1118 cm . H NMR (DMSO-d /TMS) d: 1.61 (d,
1
1
1
6
7
6
H, JZ8 Hz, SH), 3.73 (s, 3H, OMe), 3.79 (s, 3H, OMe),
.62 (d, 1H, JZ5 Hz, 6-H), 6.72 (dd, 1H, JZ5, 8 Hz, 5-H),
4
1
1
1
6
.2.4. Compound 4d. Yellowish needles (3.07 g, 84%), mp
39–140 8C. IR (KBr) n 3018, 2561, 1682, 1602, 1579,
max
1
.12–7.97 (m, 8Harom). C NMR (DMSO-d /TMS) d: 26.4
3
K1
448, 1092 cm . H NMR (DMSO-d /TMS) d: 1.58 (d,
1
6
6
(
1
5-C), 42.8 (6-C), 55.0, 55.4 (2!OMe), 127.3, 128.7, 129.5,
31.4, 132.1, 132.9, 133.6, 134.6 (2!4-MeoC H ), 165.8
H, JZ8 Hz, SH), 2.30 (s, 3H, Me), 6.58 (d, 1H, JZ5 Hz,
-H), 6.70 (dd, 1H, JZ5, 8 Hz, 5-H), 7.09–7.95 (m, 9Harom).
6
4
C
C]O), 192.5 (C]S). Mass (m/z): 391 (M ). Anal. Calcd
1
3
(
for C H NO S : C, 55.22; H, 4.38; N, 3.58%. Found: C,
C NMR (DMSO-d /TMS) d: 20.2 (Me), 25.9 (5-C), 42.3
6-C), 126.8, 127.5, 128.5, 129.2, 130.4, 131.3, 132.0,
32.6, 133.4, 134.0 (Ph, 2-MeC H ), 165.3 (C]O), 192.1
6
(
1
18 17
3 3
5
4.93; H, 4.58; N, 3.22%.
6
4
C
(
C]S). Mass (m/z): 345 (M ). Anal. Calcd for
4
.3. Isolation of the Michael adducts 7a, 7d and 7h and
C H NOS : C, 59.10; H, 4.38; N, 4.05%. Found: C,
3
1
7
15
their conversion into the corresponding final products
a, 4d and 4h
5
8.75; H, 4.57; N, 3.80%.
4
4
1
1
1
6
.2.5. Compound 4e. Yellowish needles (3.41 g, 90%), mp
43–144 8C. IR (KBr) n 3022, 2590, 1683, 1604, 1568,
452, 1091 cm . H NMR (DMSO-d /TMS) d: 1.61 (d,
The procedure followed was the same as described above
for the synthesis of 4 except that the time of MW irradiation
in this case was 4–6 min instead of 8–10 min for 4. The
adducts 7 were recrystallized from ethanol to give a
diastereomeric mixture (O97:!3; in the crude isolates
max
K1
1
6
H, JZ8 Hz, SH), 2.33 (s, 3H, Me), 6.63 (d, 1H, JZ5 Hz,
-H), 6.74 (dd, 1H, JZ5, 8 Hz, 5-H), 7.12–8.01 (m, 8Harom).
1
3
C NMR (DMSO-d /TMS) d: 20.8 (Me), 26.2 (5-C), 42.8
6-C), 126.8, 127.6, 128.7, 129.4, 130.2, 131.3, 132.1,
6
1
the ratio was O94:!6 as determined by H NMR
(
spectroscopy), which was again recrystallized from ethanol
to obtain an analytically pure sample of 7a, 7d and 7h. The
adducts 7a, 7d and 7h were assigned the erythro
1
1
32.7, 133.3, 134.1 (4-ClC H , 2-MeC H ), 165.4 (C]O),
6 4 6 4
C
92.2 (C]S). Mass (m/z): 379 (M ). Anal. Calcd for
C H ClNOS : C, 53.74; H, 3.71; N, 3.69%. Found: C,
1
7
14
3
1
stereochemistry, as their H NMR spectra exhibited lower
values of coupling constant, JcyclicSCH, acyclicSCHZ5 Hz,
5
3.95; H, 3.55; N, 3.43%.
than that of the very minor (!3%) diastereomer (threo),
4
1
1
1
.2.6. Compound 4f. Yellowish needles (2.85 g, 76%), mp
47–148 8C. IR (KBr) n 3017, 2581, 1682, 1603, 1585,
455, 1093 cm . H NMR (DMSO-d /TMS) d: 1.60 (d,
35–40
JcyclicSCH, acyclicSCHZ10 Hz.
Finely powdered inter-
max
mediate compounds 7a, 7d and 7h were intermittently MW
irradiated for 6 min in the same way as described for the
synthesis of 4 to give the corresponding annulated products
K1
1
6
H, JZ8 Hz, SH), 2.31 (s, 3H, Me), 3.76 (s, 3H, OMe), 6.61
(
d, 1H, JZ5 Hz, 6-H), 6.72 (dd, 1H, JZ5, 8 Hz, 5-H), 7.13–
4
a, 4d and 4h quantitatively.
13
.98 (m, 8Harom). C NMR (DMSO-d /TMS) d: 21.0 (Me),
7
2
1
2
6
6.1 (5-C), 42.6 (6-C), 55.1 (OMe), 126.9, 127.5, 128.9,
29.5, 130.1, 130.8, 131.6, 132.3, 132.9, 133.8 (4-MeOC H ,
-MeC H ), 165.5 (C]O), 192.0 (C]S). Mass (m/z): 375
4
1
1
.3.1. Compound 7a. Yellowish needles (2.16 g, 48%), mp
27–128 8C. IR (KBr) nmax 3148, 3008, 2971, 1776, 1604,
574, 1455, 1108, 1020 cm . H NMR (DMSO-d /TMS)
6
4
K1 1
6
4
C
6
(
M ). Anal. Calcd for C H NO S : C, 57.57; H, 4.56; N,
18 17 2 3
d: 2.34 (s, 3H, Me), 6.64 (d, 1H, JZ5 Hz, acyclic SCH),
3
.73%. Found: C, 57.27; H, 4.36; N, 3.97%.
6
9
.77 (d, 1H, JZ5 Hz, cyclic SCH), 7.14–8.00 (m, 15Harom),
13
.38 (br s, 1H, NH, exchanges with D O). C NMR
2
4
1
1
1
6
.2.7. Compound 4g. Yellowish needles (2.92 g, 81%), mp
40–141 8C. IR (KBr) n 3011, 2552, 1687, 1598, 1579,
453, 1105 cm . H NMR (DMSO-d /TMS) d: 1.59 (d,
(DMSO-d /TMS) d: 17.4 (Me), 35.0 (Me-C), 42.5 (Ar-C),
87.5 (O]C–C), 127.2, 128.6, 129.5, 130.6, 131.5, 132.7,
6
max
K1
1
6
133.6, 134.5 (2!Ph), 173.7 (C]O), 192.3 (C]S). Mass
C
H, JZ8 Hz, SH), 3.72 (s, 3H, OMe), 6.61 (d, 1H, JZ5 Hz,
(
H, 4.69; N, 3.10%. Found: C, 63.53; H, 4.45; N, 3.35%.
m/z): 451 (M ). Anal. Calcd for C H NO S : C, 63.83;
24 21 2 3
-H), 6.73 (dd, 1H, JZ5, 8 Hz, 5-H), 7.11–7.98 (m, 9Harom).
C NMR (DMSO-d /TMS) d: 25.9 (5-C), 42.4 (6-C), 54.8
1
3
6
(
1
OMe), 127.2, 128.7, 129.3, 130.4, 131.4, 132.2, 133.4,
34.3 (Ph, 4-MeOC H ), 165.7 (C]O), 192.5 (C]S). Mass
m/z): 361 (M ). Anal. Calcd for C H NO S : C, 56.48;
17 15 2 3
4.3.2. Compound 7d. Yellowish needles (2.37 g, 51%), mp
128–129 8C. IR (KBr) nmax 3147, 3010, 2970, 1775, 1603,
6
4
C
K1 1
1579, 1460, 1109, 1021 cm . H NMR (DMSO-d /TMS)
(
H, 4.18; N, 3.87%. Found: C, 56.73; H, 4.38; N, 3.52%.
6
d: 2.31 (s, 3H, Me), 2.34 (s, 3H, Me), 6.63 (d, 1H, JZ5 Hz,
acyclic SCH), 6.76 (d, 1H, JZ5 Hz, cyclic SCH), 7.14–7.98
1
O). C
3
4
1
1
1
6
.2.8. Compound 4h. Yellowish needles (3.56 g, 90%), mp
63–165 8C. IR (KBr) n 3019, 2596, 1687, 1601, 1581,
(m, 14Harom), 9.36 (br s, 1H, NH, exchanges with D
NMR (DMSO-d /TMS) d: 17.3 (Me), 20.3 (Me), 34.9
2
max
6
K1
452, 1123 cm . H NMR (DMSO-d /TMS) d: 1.62 (d,
1
(Me-C), 42.4 (Ar-C), 87.3 (O]C–C), 126.9, 127.6, 128.7,
129.2, 130.3, 131.4, 132.1, 132.7, 133.4, 134.1 (Ph, 2-Me
6
H, JZ8 Hz, SH), 3.74 (s, 3H, OMe), 6.63 (d, 1H, JZ5 Hz,
-H), 6.73 (dd, 1H, JZ5, 8 Hz, 5-H), 7.13–7.98 (m, 8Harom).
C
C H ), 173.6 (C]O), 192.1 (C]S). Mass (m/z): 465 (M ).
6 4
1
3
C NMR (DMSO-d /TMS) d: 26.5 (5-C), 42.9 (6-C), 55.5
OMe), 127.2, 128.8, 129.4, 131.3, 132.0, 132.8, 133.6,
34.4 (4-MeoC H , 4-ClC H ), 165.9 (C]O), 192.6
Anal. Calcd for C25H23NO S : C, 64.48; H, 4.98; N, 3.10%.
2 3
Found: C, 64.14; H, 4.73; N, 3.37%.
6
(
1
(
6
4
6
4
C
C]S). Mass (m/z): 395 (M ). Anal. Calcd for
4.3.3. Compound 7h. Yellowish needles (2.84 g, 55%), mp