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Med Chem Res (2012) 21:760–774
(KBr) mmax: 3228, 1638, 1599, 1518, 1469, 1368, 1218,
7.67 (m, 2H), 7.55 (d, J = 2.2 Hz, 1H), 7.42 (m, 3H), 7.06
(s, 1H), 6.72 (dd, J = 2.0, 0.7 Hz, 1H); 13C NMR
(75 MHz, CDCl3): d 193.4, 169.4, 162.1, 145.6, 145.1,
134.6, 130.8, 130.4, 129.0 (2C), 128.6 (2C), 128.3, 122.9,
120.4, 106.5, 100.0; HRESIMS: m/z [M ? H]? calcd for
C17H13O3: 265.0859, found: 265.0870.
1166, 1096, 974, 828, 732 cm-1 1H NMR (300 MHz,
;
CDCl3 ? ACETONE-d6): d 9.78 (br s, 2H, Chelated OH),
7.95 (d, J = 8.8 Hz, 1H), 7.86 (d, J = 15.2 Hz, 1H),
7.67–7.51 (m, 2H), 7.39–7.20 (m, 3H), 7.05 (d,
J = 8.8 Hz, 1H), 6.98 (d, J = 8.3 Hz, 1H), 6.91 (d,
J = 8.3 Hz, 1H), 3.95 (s, 3H); 13C NMR (75 MHz,
CDCl3 ? ACETONE-d6): d 193.3, 162.0, 159.5, 148.6,
146.1, 145.5, 123.5, 122.7, 120.2, 119.5, 117.8, 114.9,
110.3, 108.7, 107.0, 106.6, 100.0, 56.0; HRESIMS: m/z
[M ? H]? calcd for C18H15O5: 311.0914, found: 311.0929.
(E)-1-(6-hydroxybenzofuran-5-yl)-3-(4-
methoxyphenyl)prop-2-en-1-one (10b)
Yellow amorphous powder; Yield (83 mg, 92%);
Rf = 0.50 (Hexane/Ethyl acetate, 8:2); mp: 146–147°C; IR
(KBr) mmax: 3432, 1636, 1592, 1505, 1465, 1363, 1285,
1241, 1160, 1090, 1040, 822, 786 and 730 cm-1; 1H NMR
(300 MHz, CDCl3): d 13.11 (s, 1H, Chelated OH), 8.19 (s,
1H), 7.93 (d, J = 15.4 Hz, 1H), 7.66 (d, J = 8.8 Hz, 2H),
7.61 (d, J = 15.4 Hz, 1H), 7.57 (d, J = 2.2 Hz, 1H), 7.09
(s, 1H), 6.97 (d, J = 8.8 Hz, 2H), 6.76 (dd, J = 2.0,
0.7 Hz, 1H), 3.88 (s, 3H, OMe); 13C NMR (75 MHz,
CDCl3): d 193.3, 162.0, 161.9, 159.3, 145.5, 145.0, 130.4
(2C), 128.9, 127.3, 122.8, 120.0, 117.8, 114.4 (2C), 106.6,
99.9, 55.3; HRESIMS: m/z [M ? H]? calcd for C18H15O4:
295.0965, found: 295.0971.
(E)-3-(3,4-dihydroxyphenyl)-1-(4-hydroxybenzofuran-5-
yl)prop-2-en-1-one (9c)
Yellow amorphous powder; Yield (21 mg, 68%);
Rf = 0.52 (Hexane/Acetone, 6:4); mp: 216–217°C; IR
(KBr) mmax: 3410, 1678, 1595, 1447, 1361, 1292, 1164,
831, 732 cm-1 1H NMR (300 MHz, CDCl3 ? ACE-
;
TONE-d6): d 13.20 (br s, 1H, Chelated OH), 9.71 (s, 2H,
chelated OH), 8.22 (s, 1H), 7.80 (d, J = 15.2 Hz, 1H),
7.58–7.52 (m, 2H), 7.43 (br s, 1H), 7.36 (br s, 1H), 7.29 (d,
J = 8.2 Hz, 1H), 7.02 (s, 1H), 6.76 (br s, 1H); 13C NMR
(75 MHz, CDCl3 ? ACETONE-d6): d 193.2, 160.3, 159.8,
151.8, 149.4, 115.1, 114.5, 127.8, 126.0, 123.6, 118.3,
117.8, 114.6, 111.2, 110.3, 105.0, 103.7; HRESIMS: m/z
[M–H]? calcd for C17H11O5: 295.0612, found: 295.0597.
(E)-3-(3,4-dimethoxyphenyl)-1-(6-hydroxybenzofuran-5-
yl)prop-2-en-1-one (10c)
Yellow amorphous powder; Yield (80 mg, 91%); Rf = 0.40
(Hexane/Acetone, 8:2); mp: 171°C; IR (KBR) mmax: 3428,
General experimental procedure for the synthesis of linear
furanochalcones (10a–10g)
1
1625, 1569, 1460, 1398, 1280, 980, 898, 759 cm -1; H
NMR (300 MHz, CDCl3): d 13.07 (s, 1H, Chelated OH),
8.19 (s, 1H), 7.90 (d, J = 15.2 Hz, 1H), 7.59 (d,
J = 2.2 Hz, 1H), 7.56 (d, J = 15.2 Hz, 1H), 7.29 (dd,
J = 8.4, 1.8 Hz, 1H), 7.20 (d, J = 1.8 Hz, 1H), 7.08 (s,
1H), 6.92 (d, J = 8.4 Hz, 1H), 6.76 (dd, J = 2.0, 0.7 Hz,
1H), 3.98 (s, 3H, OMe), 3.95 (s, 3H, OMe); 13C NMR
(75 MHz, CDCl3): d 193.2, 162.0, 159.4, 151.6, 149.2,
145.5, 145.3, 143.4, 127.5, 123.3, 122.8, 119.9, 118.0,
117.1, 110.9, 110.1, 106.6, 99.8, 56.0; HRESIMS: m/z
[M ? H]? calcd for C19H17O5: 325.1071, found: 325.1086.
The acetophenone derivative (2) (50 mg, 0.284 mmol) was
condensed with various substituted benzaldehydes
(0.284 mmol) (7a–7g), respectively, in the presence of aq.
KOH (60%, 1 ml) in anhydrous ethanol (5 ml). The reac-
tion mixture was stirred at room temperature for 24 h and
poured into water (20 ml). After neutralization with
hydrochloric acid (10% w/v), ethanol was evaporated, and
extracted thrice with ethyl acetate (50 ml). The combined
organic phases were concentrated to yield crude products.
The crude products were subjected to column chromatog-
raphy to yield pure products (10a–10g), respectively
(Scheme 3).
(E)-1-(6-hydroxybenzofuran-5-yl)-3-(2,4,5-
trimethoxyphenyl)prop-2-en-1-one (10d)
(E)-1-(6-hydroxybenzofuran-5-yl)-3-phenylprop-2-en-1-
one (10a)
Yellow amorphous powder; Yield (85 mg, 86%);
Rf = 0.45 (Hexane/Acetone, 7:3); mp: 179–180°C; IR
(KBr) mmax: 3432, 1633, 1606, 1568, 1461, 1398, 1286,
Yellow amorphous powder; Yield (60 mg, 80%);
Rf = 0.52 (Hexane/Ethyl acetate, 9:1); mp: 121–122°C; IR
(KBr) mmax: 3339, 1741, 1669, 1593, 1510, 1463, 1430,
1209, 1130, 981, 901, 843, 804, 761 cm-1 1H NMR
;
(300 MHz, CDCl3): d 13.15 (s, 1H, Chelated OH), 8.18 (d,
J = 15.2 Hz, 1H), 8.13 (s, 1H), 7.60 (d, J = 15.2 Hz, 1H),
7.52 (d, J = 2.0 Hz, 1H), 7.11 (s, 1H), 7.04 (s, 1H), 6.72
(dd, J = 2.0, 0.7 Hz, 1H), 6.49 (s, 1H), 3.95 (s, 3H, OMe),
3.94 (s, 3H, OMe), 3.92 (s, 3H, OMe); 13C NMR (75 MHz,
1
1383, 1267, 1155, 1096, 1031, 859, 817 cm-l; H NMR
(300 MHz, CDCl3): d 12.86 (s, 1H, Chelated OH), 8.16 (s,
1H), 7.93 (d, J = 15.4 Hz, 1H), 7.71 (d, J = 15.4 Hz, 1H),
123