Med Chem Res
filtered off and recrystallised from rectified spirit to afford
(arom. –CH str.), 1653 (a,b-unsaturated keto group, –C=O
str.), 1601, 1500 (C=C arom. str., C=C olefinic str.), 1338
(asym. SO2 str.), 1178 (sym. SO2 str.), 934 (SN str.), 837
(1,4 disubstitution) cm-1; Anal. calcd. for C16H15NO3S: C
63.77, H 5.02, N 4.65, S 10.64. Found: C 63.79, H 4.98, N
4.49, S 10.78; ESI MS (m/z, relative abundance) 300 [(M-
H)?, 100].
a light brown solid. Yield 79 %; Rf = 0.72 (20 % EtOAc/
1
cyclohexane); mp 80–84 °C; H NMR (CDCl3, 500 MHz)
d 8.05 (d, J = 9 Hz, 2H), 7.82 (d, J = 15.5 Hz, 1H), 7.64
(d, J = 9 Hz, 2H), 7.51 (d, J = 15.5 Hz, 1H), 7.42 (ovlp.
d, J = 8.5 Hz, 1H),7.41–7.43 (m, 2H), 7.13 (d,
J = 8.5 Hz, 2H); 13C NMR (CDCl3, 125 MHz) d 188.6,
144.9, 144.7, 134.8, 134.7, 130.6, 130.4, 129.0, 128.4,
121.5, 119.0; IR (KBr) 3050 (arom. –CH str.), 2150 (asym.
NNN str.), 1645 (a,b-unsaturated keto group, –C=O str.),
1600, 1570 (C=C arom. str., C=C olefinic str.), 985 (oop
–CH bend. vibration of alkene), 830 (1,4 disubstitution),
775 (arom. bend.) cm-1; Anal. calcd. for C15H11N3O: C
72.28, H 4.45, N 16.86. Found: C 72.15, H 4.32, N 16.91;
ESI MS (m/z, relative abundance) 222 [(M-N2)?, 100],
250 [(M?H)?, 40].
Synthesis of 40-benzenesulphonamide chalcone 4i
(Moustafa and Ahmad, 2003)
To a solution of 4-aminoacetophenone (0.5 g, 3.7 mmol) in
dry CH2Cl2 (10 mL), Et3N (1.18 mL, 8 mmol) was added
followed by benzenesulphonyl chloride (0.51 mL, 4 mmol)
at 0 °C. After maintaining the reaction mixture between 0
and 5 °C for 3–4 h, the contents were gradually brought up to
room temperature and stirred overnight. After TLC indicated
the completion of the reaction, the mixture was diluted with
CH2Cl2 (20 mL) and washed with water (2 9 15 mL) fol-
lowed by saturated sodium chloride solution (15 mL). Dry-
ing (Na2SO4) and then distillation of the organic layer
afforded the crude acetophenone intermediate 3i as a yellow
solid. This crude 4-benzenesulphonamide acetophenone was
dissolved in rectified spirit (30 mL). Benzaldehyde
(1.01 mL, 10 mmol) was added to it followed by an aqueous
solution of 10 % KOH (10 mL). The mixture was stirred and
kept overnight at room temperature. The contents of the
reaction mixture were poured into crushed ice and acidified
with dilute HCl (0.1–0.2 N). The precipitated product was
filtered off and recrystallised from rectified spirit affording
the title compound as light yellow crystals. Yield: 16 % over
two steps; Rf = 0.44 (20 % EtOAc/cyclohexane); mp 126–
130 °C; 1H NMR (CDCl3, 500 MHz) d 7.99 (d, J = 8.5 Hz,
2H), 7.95 (d, J = 8.5 Hz, 1H), 7.94 (d, J = 8.5 Hz, 1H),
7.84 (d, J = 16 Hz, 1H) 7.70 (tt, J = 2, 8 Hz, 2H), 7.64–
7.66 (m, 2H), 7.57 (s, 1H), 7.56–7.59 (ovlp. m, 2H), 7.49 (d,
J = 16 Hz, 1H), 7.42–7.45 (m, 2H), 7.17 (dt, J = 2, 8 Hz,
2H); 13C NMR (CDCl3, 125 MHz) d 189.4, 145.8, 139.5,
139.3, 137.9, 134.6, 134.2, 131.9, 130.9, 129.3, 129.2, 129.1,
128.6, 121.5; IR (thin film) 3344 (–NH str.), 3066 (arom.
–CH str.), 1662 (a,b-unsaturated keto group, –C=O str.),
1595, 1489 (C=C arom. str., C=C olefinic str.), 1340 (asym.
SO2 str.), 1166 (sym. SO2 str.), 920 (SN str.), 867 (1,4 di-
substitution) cm-1; Anal. calcd. for C21H17NO3S: C 69.40, H
4.71, N 3.85, S 8.82. Found: C 69.29, H 4.64, N 3.78, S 8.99;
ESI MS (m/z, relative abundance) 362 [(M-H)?, 100].
Synthesis of 40-Methanesulphonamide chalcone 4h
(Zarghi et al., 2006)
To a solution of 4-aminoacetophenone (0.5 g, 3.7 mmol) in
dry CH2Cl2 (10 mL), Et3N (1.18 mL, 8 mmol) was added
followed by methanesulphonyl chloride (0.32 mL,
4 mmol) at 0 °C. After maintaining the temperature
between 0 and 5 °C for 3–4 h, the reaction mixture was
gradually warmed to room temperature and the contents
were stirred overnight. Once TLC indicated the completion
of the reaction, the mixture was diluted with CH2Cl2
(20 mL) and washed with water (2 9 15 mL) followed by
saturated sodium chloride solution (15 mL). Drying
(Na2SO4) and then distillation of the organic extracts
afforded the crude intermediate 3h as a light yellow solid.
To the crude 4-methanesulphonamide acetophenone dis-
solved in rectified spirit (30 mL), benzaldehyde (1.01 mL,
10 mmol) was added followed by an aqueous solution of
10 % KOH (10 mL). The mixture was stirred and kept
overnight at room temperature. The contents of the reaction
mixture were poured into crushed ice and acidified with
dilute HCl (0.1–0.2 N). The precipitated chalcone deriva-
tive was filtered off, recrystallised from rectified spirit and
further purified by column chromatography (20 % EtOAc/
cyclohexane) to get yellow crystals. Yield: 10 % over two
steps; Rf = 0.24 (20 % EtOAc/cyclohexane); mp 112–
116 °C; 1H NMR (CDCl3, 500 MHz)
d 8.06 (d,
J = 7.25 Hz, 1H), 8.05 (d, J = 7.25 Hz, 1H), 7.83 (d,
J = 16 Hz, 1H), 7.65 (d, J = 7.25 Hz, 1H), 7.64 (d,
J = 7.25 Hz, 1H), 7.51 (d, J = 16 Hz, 1H), 7.44 (ovlp. d,
J = 6.25 Hz, 1H), 7.43 (ovlp. d, J = 6.25 Hz, 1H), 7.42–
7.44 (m, 1H), 7.33 (d, J = 6.25 Hz, 1H), 7.32 (d,
J = 6.25 Hz, 1H), 7.15 (s, 1H), 3.12 (s, 3H); 13C NMR
(CDCl3, 125 MHz) d 188.9, 145.1, 141.1, 134.8, 134.4,
131.1, 130.7, 130.6, 129.4, 129.0, 128.5, 128.3, 121.5,
118.4, 118.2, 40.1; IR (thin film) 3248 (–NH str.), 3035
Synthesis of 20-methanesulphonamide chalcone 5a
(Batt et al., 1993)
To a solution of 20-aminochalcone (0.18 g, 0.81 mmol) in
dry CH2Cl2 (5 mL), pyridine (0.66 mL, 0.83 mmol) was
123