M. Bao et al. / Tetrahedron 60 (2004) 11359–11366
11363
131.9, 133.0, 135.4, 143.4, 166.5, 190.6, 203.6; IR (KBr):
3063, 3003, 2951, 1715, 1588, 1535, 1460, 1435, 1269,
1252, 745, 694 cmK1; Anal. calcd for C18H16O4S: C, 65.84;
H, 4.91. Found: C, 65.85; H, 4.71.
JZ7.9 Hz), 7.47 (1H, ddd, JZ8.5, 7.9, 1.5 Hz), 8.01 (1H,
dd, JZ7.6, 1.5 Hz); 13C NMR (125 MHz, CDCl3): d 14.0,
15.3, 60.7, 123.1, 124.0, 126.8, 130.9, 132.1, 142.8, 166.1;
IR (KBr): 1709, 1246, 1062, 742 cmK1
.
4.2.4. 4-Hydroxy-3-[2-(methoxycarbonyl)benzenesul-
fenyl]-3-penten-2-one (20d). Colorless crystal with mp
116.0–117.0 8C (from CH2Cl2–hexane); RfZ0.50
(dichloromethane); 1H NMR (500 MHz, CDCl3): d 2.29
(6H, s), 3.96 (3H, s), 7.06 (1H, dd, JZ8.2, 1.2 Hz), 7.19
(1H, ddd, JZ7.9, 7.3, 1.2 Hz), 7.42 (1H, ddd, JZ8.2, 7.3,
1.5 Hz), 8.07 (1H, dd, JZ7.9, 1.5 Hz), 17.38 (1H, s); 13C
NMR (125 MHz, CDCl3): d 24.3, 52.2, 101.5, 124.0, 124.3,
126.2, 132.0, 133.0, 142.5, 166.7, 198.6; IR (KBr): 2957,
1713, 1593, 1562, 1462, 1437, 1275, 1256 cmK1; Anal.
calcd for C13H14O4S: C, 58.63; H, 5.30. Found: C, 58.63; H,
5.15.
4.3.2. N,N-Bis[2-(ethoxycarbonyl)benzenesulfenyl]-2-
(methylthio)benzamide (4a). Colorless crystal with mp
165.4–166.9 8C (from dichloromethane–hexane); RfZ0.50
(dichloromethane); 1H NMR (500 MHz, CDCl3): d 1.34
(6H, t, JZ7.0 Hz), 2.55 (3H, s), 4.35 (4H, q, JZ7.0 Hz),
6.99 (1H, td, JZ7.6, 1.2 Hz), 7.17(1H, dd, JZ7.6, 1.2 Hz),
7.26 (4H, t, JZ6.1 Hz), 7.40 (1H, d, JZ7.3 Hz), 7.66 (2H, t,
JZ7.3 Hz), 7.80 (1H, brs), 8.01 (2H, d, JZ7.6 Hz); 13C
NMR (125 MHz, CDCl3): d 14.2, 18.5, 61.6, 123.4, 124.0,
124.9, 125.0, 125.9, 129.9, 130.4, 131.0, 133.4, 134.9,
137.5, 166.6, 175.8; IR (KBr): 1688, 1310, 1176, 1275,
1101, 749 cmK1; Anal. calcd for C26H25NO5S3: C, 59.18;
H, 4.78; N, 2.65. Found: C, 59.40; H, 4.60; N, 2.59.
4.2.5. Ethyl 2-cyano-2-[2-(methoxycarbonyl)benzenesul-
fenyl]acetate (2e). Colorless crystal with mp 67.3–68.3 8C
(from CH2Cl2–hexane); RfZ0.37 (dichloromethane); 1H
NMR (500 MHz, CDCl3): d 1.31 (3H, t, JZ7.0 Hz), 3.95
(3H, s), 4.30 (2H, qd, JZ7.0, 0.9 Hz), 4.86 (1H, s), 7.42
(1H, ddd, JZ7.6, 7.3, 1.2 Hz), 7.56 (1H, ddd, JZ8.2, 7.3,
1.5 Hz), 7.63 (1H, dd, JZ8.2, 1.2 Hz), 7.98 (1H, dd, JZ7.6,
1.5 Hz); 13C NMR (125 MHz, CDCl3): d 13.9, 39.0, 52.7,
63.9, 114.1, 128.1, 131.4, 131.5, 131.6, 132.9, 133.5, 163.2,
166.8; IR (KBr): 2988, 2955, 2907, 1746, 1709, 1289, 1260,
745 cmK1; Anal. calcd for C13H13NO4S: C, 55.90; H, 4.69;
N, 5.01. Found: C, 55.98; H, 4.51; N, 4.91.
4.3.3. Ethyl 2-(benzylthio)benzoate (3b). Colorless crystal
with mp 69.6–70.2 8C (from hexane) (lit.16 68.5–69 8C);
RfZ0.67 (dichloromethane); H NMR (500 MHz, CDCl3):
1
d 1.38 (3H, t, JZ7.2 Hz), 4.16 (2H, s), 4.37 (2H, q, JZ
7.2 Hz), 7.16 (1H, ddd, JZ7.8, 7.0, 1.2 Hz), 7.25 (1H, ddd,
JZ7.6, 7.0, 1.5 Hz), 7.29–7.34 (3H, m), 7.39 (1H, dd, JZ
7.6, 1.5 Hz), 7.40–7.44 (2H, m), 7.97 (1H, dd, JZ7.8,
1.2 Hz); 13C NMR (125 MHz, CDCl3): d 14.4, 37.5, 61.3,
124.2, 126.1, 127.5, 128.1, 128.7, 129.2, 131.3, 132.4,
136.3, 141.9, 166.6; IR (neat): 2978, 1705, 1277, 1250,
1148, 1063, 734, 712 cmK1
.
4.2.6. 2-(Benzenesulfonyl)-2-[2-(methoxycarbonyl)ben-
zenesulfenyl]acetonitrile (2f). Yellow oil; RfZ0.36
(dichloromethane/ethyl acetateZ4:1); 1H NMR
(500 MHz, CDCl3): d 5.34 (1H, s), 7.49 (1H, td, JZ7.6,
1.2 Hz), 7.55 (1H, td, JZ7.6, 1.8 Hz), 7.66 (2H, td, JZ7.6,
1.2 Hz), 7.76 (1H, dd, JZ7.6, 1.2 Hz), 7.79 (1H, td, JZ7.6,
1.2 Hz), 7.92 (1H, dd, JZ7.6, 1.8 Hz), 8.09 (2H, dd, JZ7.6,
1.2 Hz); 13C NMR (125 MHz, CDCl3): d 52.9, 60.5, 112.2,
129.5, 129.8, 130.4, 131.0, 131.3, 132.8, 133.8, 134.8,
135.0, 135.6, 166.8; IR (neat): 3067, 2957, 2924, 1711,
4.3.4. N,N-Bis[2-(ethoxycarbonyl)benzenesulfenyl]-2-
(benzylthio)benzamide (4b). Colorless crystal with mp
150.2–151.6 8C (from ethyl acetate–hexane); RfZ0.50
(dichloromethane); 1H NMR (500 MHz, CDCl3): d 1.32
(6H, t, JZ7.0 Hz), 4.21 (2H, s), 4.26–4.33 (4H, m), 7.02
(1H, td, JZ7.6, 0.9 Hz), 7.13–7.34 (13H, m), 7.63 (1H, brs),
8.00 (2H, d, JZ5.5 Hz); 13C NMR (125 MHz, CDCl3): d
14.3, 41.2, 61.6, 123.5, 124.0, 124.8, 124.9, 127.2, 127.3,
128.5, 129.4, 129.6, 131.0, 132.1, 133.4, 134.1, 137.1,
140.0, 143.6, 166.6, 176.0; IR (KBr) 1687, 1312, 1277,
1104, 747 cmK1; Anal. calcd for C32H29NO5S3: C, 63.66;
H, 4.84; N, 2.32. Found: C, 63.82; H, 4.71; N, 2.34.
1586, 1449, 1337, 1290, 1262, 1159, 748, 685, 588 cmK1
;
HRMS: calcd for C16H13NO4S2 347.0286, found 347.0250.
4.3. General procedure for reaction of 1 with Grignard
reagents
4.3.5. Ethyl 2-(phenylthio)benzoate (3c). Colorless oil;17
RfZ0.67 (dichloromethane); H NMR (500 MHz, CDCl3):
1
d 1.42 (3H, t, JZ7.2 Hz), 4.42 (2H, q, JZ7.2 Hz), 6.82 (1H,
dd, JZ8.1, 1.1 Hz), 7.13 (1H, td, JZ7.6, 1.1 Hz), 7.24 (2H,
ddd, JZ8.5, 7.3, 1.5 Hz), 7.41–7.44 (3H, m), 7.56 (2H, dt,
JZ7.9, 2.4 Hz), 7.99 (1H, dd, JZ7.9, 1.5 Hz); 13C NMR
(125 MHz, CDCl3): d 14.3, 61.3, 124.3, 127.2, 127.5, 129.0,
129.7, 131.0, 132.2, 132.7, 135.5, 143.0, 166.5; IR (KBr):
To a solution of 1 (0.5 mmol) in THF (10 mL) at room
temperature was added a Grignard reagent (1.0 M in THF,
0.7 mL) under a nitrogen atmosphere. The mixture was
stirred for 2 h, and then water was added to the reaction
mixture. Product was extracted with dichloromethane, and
the organic layer was washed with water and dried over
magnesium sulfate. The solvent was removed under reduced
pressure, and the crude product was purified by silica gel
column chromatography (eluent: 1:1 dichloromethane/
hexane, dichloromethane, 100:5:1 dichloromethane/
acetone/methanol).
1711, 1250, 742 cmK1
.
4.3.6. N,N-Bis[2-(ethoxycarbonyl)benzenesulfenyl]-2-
(phenylthio)benzamide (4c). Colorless crystal with mp
197.0–200.0 8C (from dichloromethane–hexane); RfZ0.50
(dichloromethane); 1H NMR (500 MHz, CDCl3): d 1.34
(6H, t, JZ7.2 Hz), 4.32 (4H, q, JZ7.0 Hz), 7.07 (1H, td,
JZ7.5, 1.2 Hz), 7.02–7.34 (11H, m), 7.41 (2H, dd, JZ7.0,
1.5 Hz), 7.58 (1H, brs), 8.00 (2H, d, JZ7.6 Hz); 13C NMR
(125 MHz, CDCl3) d 14.2, 61.5, 123.3, 124.0, 124.9, 125.5,
127.1, 129.2, 130.1, 130.7, 131.0, 132.6, 133.4, 133.5,
4.3.1. Ethyl 2-(methylthio)benzoate (3a). Colorless oil;15
1
RfZ0.67 (dichloromethane); H NMR (500 MHz, CDCl3):
d 1.40 (3H, t, JZ7.3 Hz), 2.45 (3H, s), 4.39 (2H, q, JZ
7.3 Hz), 7.15 (1H, ddd, JZ8.5, 7.6, 0.9 Hz), 7.27 (1H, d,