SYNTHESIS OF 2-AMINOCHROMENES
3481
8900 spectrometer. NMR spectra were taken with a Bruker DRX-500 spectrometer.
Elemental analyses were carried out on a Vario EL III CHNOS elemental analyzer.
Procedure for Synthesis of 2-Aminochromenes
A mixture of aldehydes (1 mmol), malononitrile (1 mmol), a- or b-naphthol
(1 mmol), and Na2HPO4 (0.05 mmol, 5 mol%) was placed in a round-bottomed flask
(25 ml) fitted with a condenser. The flask was placed in an oil bath and heated to
120 ꢀC. After completion of the reaction (monitored by thin-layer chromatography,
TLC), the mixture was diluted with water (10 ml), and the resulting solid was sepa-
rated by filtration. The crude product was recrystallized from ethanol to give the
pure product.
Selected Data
2-Amino-4-(2,3-dimethoxyphenyl)-4H-benzo[h]chromene-3-carbonitrile
(4b). Pale brown solid, mp 205–207 ꢀC; IR (KBr): 3300, 2194, 1654, 1608, 1481,
1
1375, 1263, 1105, 1066, 999, 952, 761 cmꢁ1; H NMR (500 MHz, DMSO-d6) dH
3.64 (s, 3H), 3.80 (s, 3H), 5.15 (s, 1H), 6.71 (dd, J ¼ 7.5, 1.5 Hz, 1H), 6.92 (dd,
J ¼ 8.5, 1.5 Hz, 1H), 6.99 (t, J ¼ 7.5 Hz, 1H), 7.03 (d, J ¼ 8.5 Hz, 1H), 7.11 (s, 2H),
7.54–7.58 (m, 2H), 7.63 (td, J ¼ 9.0, 1.5 Hz, 1H), 7.87 (d, J ¼ 8.0 Hz, 1H), 8.24
(d, J ¼ 7.5 Hz, 1H); 13C NMR (125 MHz, DMSO-d6) dC 55.5, 55.6, 60.3, 111.5,
117.8, 120.6, 120.7, 121.0, 122.7, 123.7, 124.1, 125.9, 126.5, 126.6, 127.6, 132.6,
138.5, 142.8, 146.1, 152.4, 160.3. Anal. calcd. for C22H18N2O: C, 73.73; H, 5.06;
N, 7.82. Found: C, 73.92; H, 5.27; N, 7.61.
2-Amino-4-(2-bromophenyl)-4H-benzo[h]chromene-3-carbonitrile (4g).
Yellow powder, mp 240–242 ꢀC; IR (KBr): 3138, 2200, 1652, 1635, 1375, 1259,
;
1122, 1066, 995, 950, 864, 750 cmꢁ1 1H NMR (500 MHz, DMSO-d6) dH 5.43
(s, 1H), 7.01 (d, J ¼ 8.0 Hz, 1H), 7.18–7.23 (m, 4H), 7.34 (t, J ¼ 7.5 Hz, 1H),
7.58–7.67 (m, 4H), 7.89 (d, J ¼ 8.5 Hz, 1H), 8.25 (d, J ¼ 8.5 Hz, 1H); 13C NMR
(125 MHz, DMSO-d6) dC 55.1, 116.6, 120.6, 120.7, 122.4, 122.6, 124.1, 125.2,
126.7, 126.9, 127.6, 128.5, 129.1, 131.4, 132.8, 132.9, 142.8, 143.9, 160.2. Anal. calcd.
for C20H13BrN2O: C, 63.68; H, 3.47; N, 7.43. Found: C, 63.82; H, 3.65; N, 7.28.
3-Amino-1-m-tolyl-1H-benzo[f]chromene-2-carbonitrile
(5b). Yellow
powder; mp 237–238 ꢀC; IR (KBr): 3458, 2189, 1658, 1591, 1409, 1228, 1082,
1
812 cmꢁ1; H NMR (500 MHz, DMSO-d6) dH 2.20 (m, 3H), 5.24 (s, 1H), 6.94–
6.97 (m, 4H), 7.00 (d, J ¼ 7.5 Hz, 1H), 7.15 (t, J ¼ 8.0 Hz, 1H), 7.34 (d, J ¼ 8.5 Hz,
1H), 7.15 (td, J ¼ 1.5, 7.5 Hz, 1H), 7.45 (td, J ¼ 1.5, 7.5 Hz, 1H), 7.84 (d, J ¼
8.0 Hz, 1H), 7.91 (d, J ¼ 9.0 Hz, 1H), 7.94 (d, J ¼ 9.0 Hz, 1H); 13C NMR
(125 MHz, DMSO-d6) dC 21.1, 57.9, 115.7, 116.8, 120.5, 123.6, 124.1, 124.8, 127.0,
127.3, 127.4, 128.4, 128.5, 129.4, 130.1, 130.7, 137.7, 145.6, 146.7, 159.6. Anal. calcd.
for C21H16N2O: C, 80.75; H, 5.16; N, 8.97. Found: C, 80.90; H, 5.32; N, 9.10.
3-Amino-1-(4-hydroxyphenyl)-1H-benzo[f]chromene-2-carbonitrile (5c).
White powder; mp 304–306 ꢀC; IR (KBr): 3452, 2194, 1651, 1589, 1415, 1236, 1083,
812 cmꢁ1; 1H NMR (500 MHz, DMSO-d6) dH 5.17 (s, 1H), 6.63 (d, J ¼ 8.5 Hz, 2H),