1954
M. A. Chowdhury et al. / Bioorg. Med. Chem. 16 (2008) 1948–1956
1H, pyridyl H-3), 7.75 (ddd, J = 8.5, 8.5, 1.8 Hz, 1H,
pyridyl H-4), 8.64 (d, J = 4.8 Hz, 1H, pyridyl H-6).
methylpyridine (9d) in 86% yield; mp 175–177 ꢂC; IR
(film): 3328, 3254 (NH2), 2222 (C„C), 1568, 1450 (Ar),
1340 (SO2) cmÀ1; 1H NMR (CDCl3 + DMSO-d6) d 2.47
(s, 3H, pyridyl C-3 Me), 7.02 (br s, 2H, SO2NH2 that ex-
changes with D2O), 7.24 (dd, J = 8.5, 4.8 Hz, 1H, pyridyl
H-5), 7.58 (d, J = 8.5 Hz, 1H, pyridyl H-4), 7.64 (d,
J = 8.5 Hz, 2H, phenyl H-2, H-6), 7.86 (d, J = 8.5 Hz,
2H, phenyl H-3, H-5), 8.5 (br resonance, 1H, pyridyl H-
6). Anal. Calcd for C14H12N2O2S: C, 61.75; H, 4.44; N,
10.29. Found: C, 61.34; H, 4.47; N, 10.00.
6.18. 1-(4-Methylthiophenyl)-2-(3-pyridyl)acetylene (18)
The product was obtained as a reddish solid using the
Sonogashira coupling reaction of 8c with 3-bromopyri-
dine (9b) in 100% yield; mp 73–75 ꢂC; IR (film): 2227
(C„C), 1577, 1558, 1494 (Ar) cmÀ1; 1H NMR (CDCl3)
d 2.51 (s, 3H, SMe), 7.20 (d, J = 8.5 Hz, 2H, phenyl H-3,
H-5), 7.32 (dd, J = 8.5, 4.8 Hz, 1H, pyridyl H-5), 7.50 (d,
J = 8.5 Hz, 2H, phenyl H-2, H-6), 7.82 (d, J = 8.5 Hz,
1H, pyridyl H-4), 8.54 (d, J = 4.8 Hz, 1H, pyridyl H-
6), 8.76 (s, 1H, pyridyl H-2).
6.23. General procedure for the synthesis of 1-(metha-
nesulfonylphenyl)-2-(pyridyl)acetylenes (23–32)
An aqueous solution of Oxoneꢁ (50% w/v, 3 mmol) was
added dropwise to a stirred solution of a 1-(methylthi-
ophenyl)-2-(pyridyl)acetylene 10–19 (1 mmol) in 1,4-
dioxane (10 mL) at 0 ꢂC, and the reaction was allowed
to proceed with stirring at 25 ꢂC for 4–5 h. The reaction
mixture was diluted with water (15 mL), extracted with
EtOAc (3 · 25 mL), the organic phase was washed suc-
cessively with water and brine, and dried (MgSO4).
After filtration, the solvent from the organic fraction
was removed in vacuo to give a crude product which
was purified by silica gel column chromatography using
hexanes/EtOAc as eluent to afford the respective prod-
uct 23–32. The spectral and microanalytical data for
compounds 23–32 are listed below.
6.19. 1-(4-Methylthiophenyl)-2-(3-methyl-2-pyridyl)acet-
ylene (19)
The product was obtained as reddish crystals using the
Sonogashira coupling reaction of 8c with 2-bromo-3-
methylpyridine (9d) in 91% yield; mp 55–57 ꢂC; IR (film):
1
2220 (C„C), 1581, 1563, 1491 (Ar) cmÀ1; H NMR
(CDCl3 + D2O) d 2.51 (s, 3H, SMe), 2.52 (s, 3H, pyridyl
C-3 Me), 7.16 (dd, J = 8.5, 4.8 Hz, 1H, pyridyl H-5),
7.25 (d, J = 8.5 Hz, 2H, phenyl H-3, H-5), 7.52 (d,
J = 8.5 Hz, 2H, phenyl H-2, H-6), 7.58 (d, J = 8.5 Hz,
1H, pyridyl H-4), 8.46 (d, J = 4.8 Hz, 1H, pyridyl H-6).
6.20. 1-(4-Aminosulfonylphenyl)-2-(2-pyridyl)acetylene (20)
6.24. 1-(2-Methanesulfonylphenyl)-2-(2-pyridyl)acetylene
(23)
The product was obtained as pale yellow solid using the
Sonogashira coupling reaction of 8d with 2-bromopyri-
dine (9a) in 83% yield; mp 163–165 ꢂC; IR (film): 3316,
3259 (NH2), 2223 (C„C), 1568, 1450 (Ar), 1333 (SO2)
Yield, 66%; pale yellow solid; mp 155–157 ꢂC; IR (film):
2224 (C„C), 1582, 1475 (Ar), 1313 (SO2) cmÀ1 1H
;
1
cmÀ1; H NMR (CDCl3 + DMSO-d6) d 7.25–7.50 (m,
NMR (CDCl3) d 3.35 (s, 3H, SO2Me), 7.35 (dd,
J = 8.5, 4.8 Hz, 1H, pyridyl H-5), 7.53–7.72 (m, 3H, phe-
nyl H-4, H-5, pyridyl H-3), 7.76 (dd, J = 8.5, 1.8 Hz, 1H,
phenyl H-6), 7.80 (ddd, J = 8.5, 8.5, 1.2 Hz, 1H, pyridyl
H-4), 8.15 (d, J = 8.5 Hz, 1H, phenyl H-3), 8.65 (d,
J = 4.8 Hz, 1H, pyridyl H-6). Anal. Calcd for
C14H11NO2SÆ1/4H2O: C, 64.23; H, 4.39; N, 5.35. Found:
C, 64.54; H, 4.49; N, 5.27.
2H, SO2NH2 that exchanges with D2O), 7.32 (dd,
J = 8.5, 4.8 Hz, 1H, pyridyl H-5), 7.52 (d, J = 8.5 Hz,
1H, pyridyl H-3), 7.66 (d, J = 8.5 Hz, 2H, phenyl H-2,
H-6), 7.74 (dd, J = 8.5, 8.5 Hz, 1H, pyridyl H-4), 7.84
(d, J = 8.5 Hz, 2H, phenyl H-3, H-5), 8.56 (d,
J = 4.8 Hz, 1H, pyridyl H-6). Anal. Calcd for
C13H10N2O2SÆ1/4H2O: C, 59.42; H, 4.00; N, 10.66.
Found: C, 59.76; H, 3.98; N, 10.27.
6.25. 1-(2-Methanesulfonylphenyl)-2-(3-pyridyl)acetylene
(24)
6.21. 1-(4-Aminosulfonylphenyl)-2-(4-pyridyl)acetylene (21)
The product was obtained as pale yellow solid using the
Sonogashira coupling reaction of 8d with 4-bromopyri-
dine (9c) in 44%; mp 230–232 ꢂC; IR (film): 3349, 3261
(NH2), 2220 (C„C), 1568, 1450 (Ar), 1340 (SO2)
Yield, 59%; red syrup; IR (film): 2222 (C„C), 1561,
1
1482 (Ar), 1310 (SO2) cmÀ1; H NMR (CDCl3) d 3.30
(s, 3H, SO2Me), 7.39 (dd, J = 8.5, 4.8 Hz, 1H, pyridyl
H-5), 7.57 (dd, J = 8.5, 8.5 Hz, 1H, phenyl H-5), 7.68
(ddd, J = 8.5, 8.5, 1.8 Hz, 1H, phenyl H-4), 7.78 (d,
J = 8.5 Hz, 1H, phenyl H-6), 7.96 (d, J = 8.5 Hz, 1H,
pyridyl H-4), 8.16 (d, J = 8.5 Hz, 1H, phenyl H-3),
8.63 (d, J = 4.8 Hz, 1H, pyridyl H-6), 8.82 (s, 1H, pyri-
dyl H-2). Anal. Calcd for C14H11NO2SÆ1/5H2O: C,
64.45; H, 4.37; N, 5.37. Found: C, 64.64; H, 4.73; N,
5.02.
1
cmÀ1; H NMR (CDCl3 + DMSO-d6) d 7.32–7.62 (m,
4H, pyridyl H-3, H-5; SO2NH2 that exchanges with
D2O), 7.7 (d, J = 8.5 Hz, 2H, phenyl H-2, H-6), 7.88
(d, J = 8.5 Hz, 2H, phenyl H-3, H-5), 8.5–9.5 (br reso-
nance, 2H total, pyridyl H-2, H-6). Anal. Calcd for
C13H10N2O2S: C, 60.45; H, 3.90; N, 10.85. Found: C,
60.37; H, 4.05; N, 10.42.
6.22. 1-(4-Aminosulfonylphenyl)-2-(3-methyl-2-pyri-
dyl)acetylene (22)
6.26. 1-(2-Methanesulfonylphenyl)-2-(4-pyridyl)acetylene
(25)
The product was obtained as pale yellow solid using the
Sonogashira coupling reaction of 8d with 2-bromo-3-
Yield, 32%; pale yellow solid; mp 165–167 ꢂC; IR (film):
2225 (C„C), 1597, 1477, 1465 (Ar), 1310 (SO2) cmÀ1
;