Koneni V. Sashidhara et al.
FULL PAPERS
202–2048C. 1H NMR (CDCl3, 400 MHz): d=9.07
(s, 1H),
100–1108C for 40 min. After completion of the reaction, the
mixture was treated with aqueous Na2S2O3 solution (5%,
10 mL) and the product was extracted with chloroform (3ꢀ
20 mL). The combined organic layers were dried with anhy-
drous sodium sulfate, concentrated under vacuum and puri-
fied by column chromatography (100–200 mesh) (3:97 ethyl
acetate: hexane) to afford the pure 1-(4-Methoxyphenyl)-2-
(2-p-tolylchromen-4-ylidene)-ethanone (5a) as a light yellow
solid; yield: 74%; mp 155–1388C. 1H NMR (CDCl3,
300 MHz): d=8.88 (s, 1H), 8.03 (d, 2H, J=8.7 Hz), 7.94
(bd, 1H, J=7.9 Hz), 7.87 (d, 2H, J=8.2 Hz), 7.48 (t, 1H,
J=8.2 Hz), 7.35 (d, 1H, J=8.1 Hz), 7.30–7.24 (m, 3H), 7.09
(s, 1H), 6.96 (d, 2H, J=8.7 Hz), 3.86 (s, 3H), 2.40 (s, 3H);
13C NMR (CDCl3, 75 MHz): d=189.1, 162.6, 155.9, 153.1,
142.0, 140.9, 134.4, 131.5, 129.9, 129.6, 126.0, 124.9, 123.2,
120.8, 118.6, 113.7, 102.9, 102.4, 55.5, 21.6; IR (KBr): n=
3041, 1732, 1599, 1018 cmÀ1; ESI-MS: m/z=369 (M+H)+;
HR-MS: m/z=369.1447, calcd. for C25H20O3 (M+H)+:
369.1491.
8.37–8.34 (m, 4H), 8.20–8.15 (m, 4H), 8.03 (d, J=7.8 Hz,
1H), 7.65 (t, J=7.4 Hz, 1H), 7.49 (d, J=8.0 Hz, 1H), 7.44–
7.38 (m, 1H), 7.16 (s, 1H). 13C NMR (CDCl3, 100 MHz): d=
189.3, 155.2, 153.1, 142.8, 139.7, 138.1, 136.9, 132.1, 131.8,
129.3, 129.2, 128.9, 127.4, 125.4, 123.3, 120.4, 118.7, 103.2,
103.0, 103.0, 102.8, 61.1, 61.0, 56.5; IR (KBr): n=3027, 1705,
1599, 1007 cmÀ1; ESI-MS: m/z=415 (M+H)+; anal. calcd.
for C23H14N2O6: C 66.67, H 3.41, N, 6.76; found: C 66.89, H
3.20, N 6.91.
1-(3,4,5-Trimethoxyphenyl)-2-[2-(3,4,5-trimethoxyphenyl)-
chromen-4-ylidene]ethanone (3i): Light yellow solid; yield:
1
72%; mp 125–1278C. H NMR (CDCl3, 300 MHz): d=8.82
(s, 1H), 7.98 (d, 1H, J=7.4 Hz), 7.59–7.54 (m, 1H), 7.45 (d,
1H, J=7.4 Hz), 7.37–7.33 (m, 1H), 7.27 (s, 2H), 7.20 (s,
2H), 7.05 (s, 1H,), 3.99 (s, 6H), 3.97 (s, 6H), 3.93 (s, 3H),
3.92 (s, 3H); 13C NMR (CDCl3, 75 MHz): d=189.6, 156.0,
153.5, 153.1, 153.0, 142.6, 141.5, 140.6, 137.1, 131.8, 128.1,
125.2, 123.2, 120.5, 118.6, 105.3, 103.6, 103.0, 102.8, 61.1,
61.0, 56.5; IR (KBr): n=3049, 1712, 1592, 1008 cmÀ1; ESI-
MS: m/z=505 (M+H)+; anal. calcd. for C29H28O8: C 69.04,
H 5.59; found: C 69.15, H 5.47.
2-(6-Hydroxy-2-p-tolylchromen-4-ylidene)-1-p-tolylethan-
one (3j): Greenish solid; yield: 62%; mp 142–1438C.
1H NMR (CDCl3 +TFA-d1, 300 MHz): d=8.35 (s,1H), 8.25
(d, 2H, J=6.2 Hz), 8.17 (d, 1H, J=7.0 Hz), 7.99 (d, 2H, J=
6.0 Hz), 7.87 (dd, 1H, J=7.0 and 1.9 Hz), 7.56 (d, 2H, J=
6.1 Hz), 7.50 (s, 1H), 7.41 (d, 2H, J=6.0 Hz), 7.26 (s, 1H),
2.56 (s, 3H), 2.49 (s, 3H); 13C NMR (DMSO-d6, 75 MHz):
d=188.1, 156.0, 155.0, 152.5, 141.2, 140.7, 132.4, 132.2, 130.7,
130.1, 129.7, 125.7, 124.4, 120.4, 118.7, 116.5, 115.6, 103.5,
101.7; 21.5, 21.4; IR (KBr): n=3428, 3021, 1723, 1619,
1020 cmÀ1; ESI-MS: m/z=369 (M+H)+; anal. calcd. for
C25H20O3: C 81.62, H 5.47; found: C 81.50, H 5.35.
2-(6-Hydroxy-2-m-tolylchromen-4-ylidene)-1-m-tolyleth-
anone (3k): Greenish solid; yield: 63%; mp 132–1348C.
1H NMR (DMSO-d6, 300 MHz): d=9.85 (s, 1H), 8.82 (s,
1H), 7.90–7.86 (m, 2H), 7.75 (s, 2H), 7.57 (d, 1H, J=
2.5 Hz), 7.49–7.44 (m, 2H), 7.42–7.36 (m, 3H), 7.14 (dd, 1H,
J=9.0 and 2.6 Hz), 7.09 (s, 1H), 2.43 (s, 3H), 2.42 (s, 3H);
13C NMR (DMSO-d6, 75 MHz): d=188.1, 156.1, 154.9,
152.6, 141.2, 140.7, 132.5, 132.3, 130.7, 130.1, 129.7, 125.7,
124.4, 120.4, 118.7, 116.5, 115.6, 103.6, 101.7, 21.5, 21.4; IR
(KBr): n=3394, 3028, 1716, 1587, 1003 cmÀ1; ESI-MS: m/z=
369 (M+H)+; anal. calcd. for C25H20O3: C 81.62, H 5.47;
found: C 81.73, H 5.23.
The compounds (5b–f and 6a–c) have been synthesized by
similar procedures as described above for 5a.
1-(3,4-Dimethoxyphenyl)-2-(2-p-tolylchromen-4-ylidene)-
ethanone (5b): Light yellow solid; yield: 76%; mp 157–
1598C. 1H NMR (CDCl3, 300 MHz): d=8.89 (s, 1H), 7.96
(bd, 1H, J=7.7 Hz), 7.87 (d, 2H, J=8.2 Hz), 7.68–7.65 (m,
2H), 7.53–7.47 (m, 1H), 7.38–7.35 (m, 1H), 7.31–7.24 (m,
3H), 7.11 (s, 1H), 6.9 (d, 1H, J=8.1 Hz), 3.98 (s, 3H), 3.95
(s, 3H,), 2.40 (s, 3H); 13C NMR (CDCl3, 75 MHz): d=188.9,
156.0, 153.1, 152.3, 149.2, 142.2, 141.0, 134.6, 131.6, 129.9,
129.6, 126.0, 124.9, 123.2, 121.6, 120.7, 118.6, 110.6, 110.1,
102.6, 102.4, 56.1, 21.6; IR (KBr): n=3020, 1726, 1592,
1013 cmÀ1; ESI-MS: m/z=399 (M+H)+; anal. calcd. for
C26H22O4: C 78.37, H 5.57; found: C 78.25, H 5.67.
2-(2-p-Tolylchromen-4-ylidene)-1-(3,4,5-trimethoxyphen-
yl)ethanone (5c): Light yellow solid; yield: 78%; mp 120–
1218C. 1H NMR (CDCl3, 300 MHz): d=8.91 (s, 1H), 7.98
(d, 1H, J=8.0 Hz), 7.91 (d, 2H, J=8.1 Hz), 7.6–7.5 (m,
1H), 7.43 (d, 1H, J=8.0 Hz), 7.36–7.26 (m, 5H), 7.05 (s,
1H), 3.97 (s, 6H), 3.93 (s, 3H,), 2.43 (s, 3H); 13C NMR
(CDCl3, 75 MHz): d=189.3, 156.5, 155.8, 153.2, 142.9, 141.2,
137.1, 133.9, 131.8, 129.8, 129.6, 126.1, 125.1, 123.2, 120.6,
118.8, 105.4, 102.5, 102.4, 61.1, 56.5, 21.6; IR (KBr): n=
3009, 1741, 1533, 1010 cmÀ1; ESI-MS: m/z=429 (M+H)+;
anal. calcd .for C27H24O5: C 75.68, H 5.65; found: C 75.80, H
5.52.
1-(4-Hydroxyphenyl)-2-(2-p-tolylchromen-4-ylidene)eth-
anone (5d): Light yellow solid; yield: 74%; mp 167–1688C.
1H NMR (DMSO-d6, 300 MHz): d=10.19 (s, 1H), 8.8 (s,
1H), 8.36 (d, 1H, J=7.7 Hz), 8.01 (d, 2H, J=8.6 Hz), 7.83
(d, 2H, J=8.1 Hz), 7.67–7.62 (m, 1H), 7.53 (s, 1H, J=7.5),
7.43–7.38 (m, 3H), 7.31 (s, 1H,), 6.88 (d, 2H), 2.39 (s, 3H);
13C NMR (DMSO-d6, 75 MHz): d=188.2, 161.6, 154.9,
152.6, 141.2, 140.7, 132.5, 132.3, 130.7, 130.1, 129.7, 127.9,
125.8, 124.5, 120.4, 118.7, 116.5, 115.5, 103.5, 101.8, 21.5; IR
(KBr): n=3452, 3043, 1742, 1518, 1031 cmÀ1; ESI-MS: m/z=
355 (M+H)+; anal. calcd. for C24H18O3: C 81.34, H 5.12;
found: C 81.45, H 5.0.
2-(6-Hydroxy-2-phenylchromen-4-ylidene)-1-phenyleth-
anone (3l): Greenish solid; yield: 62%; mp 136–1378C.
1H NMR (DMSO-d6, 300 MHz): d=9.86 (s, 1H), 8.86 (s,
1H), 8.10 (d, 2H, J=6.8 Hz), 7.96 (bd, 2H, J=7.6 Hz),
7.60–7.47 (m, 8H), 7.17–7.13 (m, 2H); 13C NMR (CDCl3,
75 MHz): d=189.4, 155.7, 155.4, 146.4, 142.3, 141.1, 132.6,
132.2, 131.3, 129.6, 129.0, 128.1, 126.0, 121.5, 120.9, 120.1,
108.0, 102.7, 101.6; IR (KBr): 3398, 3025, 1729, 1570,
1023 cmÀ1; ESI-MS: m/z=341 (M+H)+; anal. calcd. for
C23H16O3: C 81.16, H 4.74; found: C 81.08, H 4.82.
1-(3,4-Dimethoxyphenyl)-2-[2-(4-methoxyphenyl)chro-
men-4-ylidene]ethanone (5e): Light yellow solid; yield:
75%; mp 167–1688C. H NMR (CDCl3, 300 MHz): d=8.87
Representative Synthesis of 1-(4-Methoxyphenyl)-2-
(2-p-tolyl-chromen-4-ylidene)ethanone (5a):
1
A mixture 2-hydroxychalcone 4b (0.8 mmol), 4-methoxyace-
tophenone 2a (0.8 mmol) and I2 (0.08 mmol) was heated at
(s, 1H), 7.98–7.93 (m, 3H), 7.69–7.66 (m, 2H), 7.51 (t, 1H,
J=10.8 Hz), 7.36 (d, 1H, J=7.4 Hz), 7.29 (t, 1H, J=
1138
ꢁ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 2012, 354, 1129 – 1140