6
G.K. Verma et al. / Tetrahedron xxx (2013) 1e8
4.2.1. 3-Benzoyl-5-hydroxy-2-methylthio-benzofuran (3aa). Yellow
solid; mp: 212e213 ꢂC (lit.8c 212e214 ꢂC); 1H NMR (300 MHz,
1H, ArH); 2.62 (s, 3H, SMe); 13C NMR (75 MHz, DMSO-d6):
165.0, 149.6, 148.8, 137.7, 133.2, 130.6, 129.0, 128.5, 127.2, 126.7,
d 190.5,
DMSO-d6):
d
9.33 (s, 1H, OH, D2O exchangeable); 7.68e7.63 (m, 3H,
126.5, 125.3, 124.4, 116.5, 112.0, 111.1, 104.9, 13.1; IR (KBr): n 3190,
ArH); 7.54 (t, J¼7.5 Hz, 2H, ArH); 7.42 (d, J¼9.0 Hz, 1H, ArH); 6.68
2980, 2706, 1604, 1460, 1378, 1209, 1170 cmꢀ1; HRMS [ESI, (MþH)þ]
(dd, J¼8.7 and 1.8 Hz, 1H, ArH); 6.52 (d, J¼2.4 Hz, 1H, ArH); 2.62 (s,
calcd for C20H14O3S: 335.0742, found 335.0745.
3H, SMe); 13C NMR (75 MHz, DMSO-d6):
d 189.6, 163.1, 154.2, 148.8,
139.0, 132.2, 128.6, 128.0, 126.9, 115.6, 112.3, 111.2, 105.0, 13.4; IR
4.2.8. 5-Hydroxy-2-methylthio-3-(thien-2-carbonyl)-benzofuran
3263, 2925, 2852, 1604, 1457, 1364, 1220, 1152 cmꢀ1
.
(3ha). Yellow solid; mp: 163e164 ꢂC; 1H NMR (300 MHz, CDCl3):
(KBr):
n
d
7.75 (d, J¼3.6 Hz, 1H, ArH); 7.69 (d, J¼5.1 Hz, 1H, ArH); 7.31 (d,
4.2.2. 5-Hydroxy-3-(4-methylbenzoyl)-2-methylthio-benzofuran
J¼9.0 Hz, 1H, ArH); 7.15e7.12 (m, 1H, ArH); 7.07 (d, J¼2.1 Hz, 1H,
ArH); 6.78 (dd, J¼9.0 and 2.4 Hz, 1H, ArH); 6.23 (s, 1H, OH, D2O
exchangeable); 2.64 (s, 3H, SMe); 13C NMR (75 MHz, CDCl3þDMSO-
(3ba). Yellow solid; mp: 188e189 ꢂC; 1H NMR (300 MHz, CDCl3):
d
7.68 (d, J¼7.8 Hz, 2H, ArH); 7.32e7.25 (m, 3H, ArH); 6.94 (d,
J¼2.4 Hz, 1H, ArH); 6.75 (dd, J¼9.0 and 2.1 Hz, 1H, ArH); 5.36 (s,
d6): d 181.3, 161.2, 153.8, 149.6, 144.0, 133.0, 127.5, 126.7, 117.2, 115.6,
1H, OH, D2O exchangeable); 2.63 (s, 3H, SMe); 2.44 (s, 3H, ArMe);
112.5, 110.5, 105.4, 14.0; IR (KBr):
n 3069, 2924, 2850, 1586, 1467,
13C NMR (75 MHz, CDCl3þDMSO-d6):
d 189.8, 162.5, 153.7, 149.3,
1344, 1232, 1139 cmꢀ1; HRMS [ESI, (MþH)þ] calcd for C14H10O3S2:
142.4, 136.3, 128.7, 128.5, 127.1, 116.7, 112.0, 110.4, 105.6, 21.3, 13.6;
291.0150, found 291.0158.
IR (KBr):
n ;
3201, 2923, 2852, 1597, 1447, 1372, 1224, 1161 cmꢀ1
HRMS [ESI, (MþH)þ] calcd for C17H14O3S: 299.0742, found
4.2.9. 3-(Furan-2-
(3ia). Yellow solid; mp: 167e168 ꢂC; 1H NMR (300 MHz, CDCl3):
7.68 (s,1H, ArH); 7.34e7.31 (m, 2H, ArH); 6.78 (dd, J¼8.7 and 2.4 Hz,
carbonyl)-5-hydroxy-2-methylthio-benzofuran
299.0744.
d
4.2.3. 5-Hydroxy-3-(4-methoxybenzoyl)-2-methylthio-benzofuran
1H, ArH); 6.71 (s, 2H, ArH); 5.08 (s,1H, OH, D2O exchangeable); 2.65
(3ca). Yellow solid; mp: 155e156 ꢂC; 1H NMR (300 MHz, CDCl3):
(s, 3H, SMe); 13C NMR (75 MHz, CDCl3þDMSO-d6):
d 184.1, 153.7,
d
7.78 (dd, J¼8.7 and 4.2 Hz, 2H, ArH); 7.26 (d, J¼3.0 Hz, 1H, ArH);
149.5, 145.8, 126.3, 118.2, 115.6, 112.2, 111.9, 110.4, 105.8, 13.7; IR
6.97 (d, J¼8.4 Hz, 1H, ArH); 6.71 (s, 3H, ArH); 4.48 (s, 1H, OH, D2O
(KBr):
n
3309, 2925, 1584, 1465, 1376, 1247, 1174 cmꢀ1; HRMS [ESI,
exchangeable); 3.89 (s, 3H, OMe); 2.63 (s, 3H, SMe); 13C NMR
(MþH)þ] calcd for C14H10O4S: 275.0378, found 275.0375.
(75 MHz, CDCl3þDMSO-d6):
d 189.5, 162.8, 153.8, 149.7, 131.0, 115.8,
113.4, 112.2, 110.6, 105.7, 55.2, 13.9; IR (KBr):
n 3218, 2929, 2843,
4.2.10. 5-Hydroxy-2-methylthio-3-(pyridyl-3-carbonyl)-benzofuran
1590, 1453, 1360, 1264, 1151 cmꢀ1; HRMS [ESI, (MþH)þ] calcd for
(3ja). Brown solid; mp: 128e129 ꢂC; 1H NMR (300 MHz, DMSO-
C
17H14O4S: 315.0691, found 315.0696.
d6): d 9.31 (s, 1H, OH, D2O exchangeable); 9.15 (s, 1H, ArH); 8.73 (d,
J¼3.9 Hz, 1H, ArH); 8.30 (d, J¼7.8 Hz, 1H, ArH); 7.53 (dd, J¼7.5 and
4.8 Hz, 1H, ArH); 6.93e6.89 (m, 1H, ArH); 6.79e6.70 (m, 1H, ArH);
6.57e6.55 (m, 1H, ArH); 2.69 (s, 3H, SMe); 13C NMR (75 MHz,
4.2.4. 3-(4-Chlorobenzoyl)-5-hydroxy-2-methylthio-benzofuran
(3da). Brown solid; mp: 183e184 ꢂC; 1H NMR (300 MHz, CDCl3):
d
7.71 (d, J¼8.1 Hz, 2H, ArH); 7.46 (d, J¼8.4 Hz, 2H, ArH); 7.32 (d,
DMSO-d6):
d 182.8, 167.9, 152.2, 150.1, 148.8, 145.5, 135.2, 133.9,
J¼8.7 Hz, 1H, ArH); 6.78 (dd, J¼8.4 and 2.1 Hz, 1H, ArH); 6.74 (d,
J¼2.4 Hz, 1H, ArH); 5.00 (s, 1H, OH, D2O exchangeable); 2.66 (s, 3H,
123.7, 117.0, 116.0, 115.6, 114.7, 109.0, 14.4; IR (KBr):
n 3418, 3090,
2950, 1626, 1590, 1465, 1384, 1204, 1117 cmꢀ1; HRMS [ESI, (MþH)þ]
SMe); 13C NMR (75 MHz, CDCl3):
d 189.7, 164.5, 152.9, 150.2, 138.5,
calcd for C15H11NO3S: 286.0538, found 286.0538.
137.5, 130.0, 128.8, 127.5, 116.4, 112.3, 111.1, 106.0, 14.0; IR (KBr):
n
3214, 2925, 2854, 1600, 1456, 1358, 1240, 1133 cmꢀ1; HRMS [ESI,
(MþH)þ] calcd for C16H11ClO3S: 319.0196, found 319.0192.
4.2.11. 3-Carboethoxyl-5-hydroxy-2-methylthio-benzofuran (3ka). -
White solid; mp: 152e153 ꢂC (lit.8c 156e158 ꢂC); 1H NMR
(300 MHz, CDCl3):
2.4 Hz, 1H, ArH); 4.81 (s, 1H, OH, D2O exchangeable); 4.40 (q,
d
7.31e7.28 (m, 2H, ArH); 6.72 (dd, J¼8.7 and
4.2.5. 3-(Biphenyl-4-carbonyl)-5-hydroxy-2-methylthio-benzofuran
(3ea). Yellow solid; mp: 191e192 ꢂC; 1H NMR (300 MHz, CDCl3):
J¼7.2 Hz, 2H, OCH2); 2.68 (s, 3H, SMe); 1.43 (t, J¼6.9 Hz, 3H, CH3);
d
7.85 (d, J¼8.1 Hz, 2H, ArH); 7.71 (d, J¼8.1 Hz, 3H, ArH); 7.67 (d,
13C NMR (75 MHz, CDCl3):
d 164.3, 163.3, 152.9, 150.0, 127.7, 111.6,
J¼7.5 Hz, 2H, ArH); 7.50e7.31 (m, 4H, ArH); 6.89 (d, J¼2.4 Hz, 1H,
ArH); 5.04 (s, 1H, OH, D2O exchangeable); 2.66 (s, 3H, SMe); 13C
110.8, 109.9, 106.1, 103.3, 60.6, 14.4, 13.2; IR (KBr):
n 3289, 2926,
1662, 1593, 1496, 1346, 1268, 1134 cmꢀ1
.
NMR (75 MHz, CDCl3): d 186.6, 178.6, 170.7, 157.1, 155.3, 137.1, 135.0,
134.5, 133.0, 129.3, 128.9, 127.2, 127.1, 122.7, 99.9, 14.0; IR (KBr):
n
3418, 2926, 1598, 1464, 1370, 1244, 1190, 1165 cmꢀ1; HRMS [ESI,
4.2.12. 3-(2,2-Dimethylpropionyl)-5-hydroxy-2-methylthio-benzofu-
ran (3la). Brown solid; mp: 132e133 ꢂC; 1H NMR (300 MHz,
(MþH)þ] calcd for C22H16O3S: 361.0898, found 361.0890.
CDCl3):
d
7.30 (d, J¼8.7 Hz,1H, ArH); 7.18 (d, J¼2.4 Hz,1H, ArH); 6.75
(dd, J¼9.0 and 2.4 Hz, 1H, ArH); 4.75 (s, 1H, OH, D2O exchangeable);
4.2.6. 3-(2-Chlorobenzoyl)-5-hydroxy-2-methylthio-benzofuran
2.60 (s, 3H, SMe); 1.40 (s, 9H, 3ꢁ CH3); 13C NMR (75 MHz, CDCl3):
(3fa). Yellow solid; mp: 157e158 ꢂC; 1H NMR (300 MHz, CDCl3):
d
202.3, 173.3, 165.2, 152.0, 150.5, 126.3, 116.8, 111.5, 111.2, 107.7,
d
7.47e7.38 (m, 3H, ArH); 7.28 (d, J¼8.7 Hz, 1H, ArH); 6.85 (s, 1H,
43.3, 26.1, 14.3; IR (KBr):
n 3330, 2926, 1599, 1451, 1354, 1287,
ArH); 6.75 (d, J¼2.4 Hz, 1H, ArH); 6.72 (d, J¼5.1 Hz, 1H, ArH);
1185 cmꢀ1; HRMS [ESI, (MþH)þ] calcd for C14H16O3S: 265.0898,
5.36 (s, 1H, OH, D2O exchangeable); 2.64 (s, 3H, SMe); 13C NMR
found 265.0896.
(75 MHz, CDCl3þDMSO-d6):
d 188.2, 165.4, 154.2, 149.6, 149.4,
139.7, 130.7, 130.1, 129.7, 127.7, 127.0, 115.7, 112.0, 110.4, 105.4,
4.2.13. 5-Hydroxy-3-(4-methylbenzoyl)-2-methylthio-naphtho[1,2-
13.3; IR (KBr):
n ;
3160, 2997, 1584, 1470, 1380, 1271, 1163 cmꢀ1
b]furan (3bb). Yellow solid; mp: 165e166 ꢂC; 1H NMR (300 MHz,
HRMS [ESI, (MþH)þ] calcd for C16H11ClO3S: 319.0196, found
CDCl3):
d
8.78 (s, 1H, OH, D2O exchangeable); 8.29 (d, J¼8.4 Hz, 1H,
319.0190.
ArH); 8.17 (d, J¼8.1 Hz, 1H, ArH); 7.76 (d, J¼7.8 Hz, 2H, ArH); 7.59
(t, J¼7.8 Hz, 1H, ArH); 7.47 (t, J¼7.8 Hz, 1H, ArH); 7.30 (d, J¼7.8 Hz,
2H, ArH); 6.94 (s, 1H, ArH); 2.72 (s, 3H, SMe); 2.45 (s, 3H, ArMe);
4.2.7. 5-Hydroxy-2-methylthio-3-(1-naphthoyl)-benzofuran (3ga).-
Yellow solid; mp: 164e165 ꢂC; 1H NMR (300 MHz, DMSO-d6):
13C NMR (75 MHz, CDCl3þDMSO-d6):
d 192.7, 178.8, 174.3, 168.5,
d
9.23 (s, 1H, OH, D2O exchangeable); 8.15 (d, J¼6.6 Hz, 1H, ArH);
155.7, 150.0, 136.1, 128.7, 128.6, 126.5, 123.8, 123.0, 120.3, 118.8,
8.06 (d, J¼7.8 Hz, 1H, ArH); 7.83 (d, J¼8.1 Hz, 1H, ArH); 7.64e7.52
99.6, 21.3, 14.3; IR (KBr):
n 3196, 2930, 1589, 1432, 1348, 1249,
(m, 5H, ArH); 7.41 (d, J¼8.7 Hz, 1H, ArH); 6.64 (dd, J¼9.0 and 2.4 Hz,