C. Chen et al.
J = 7.8 Hz, 1H), 7.05 (s, 1H), 4.47 (d, J = 11.1 Hz, 1H), 4.10–4.00 (m, 2H), 3.19
(d, J = 18.0 Hz, 1H), 2.89 (d, J = 18.0 Hz, 1H), 2.72 (d, J = 11.1 Hz, 1H), 2.41
(s, 3H), 1.44 (s, 3H), 1.04 (t, J = 7.2 Hz, 3H). 13C NMR (75 MHz, CDCl3) d (ppm):
174.0, 159.6, 152.8, 150.7, 146.75, 146.68, 142.7, 128.3, 125.6, 123.9, 123.7, 121.3,
116.96, 116.90, 68.5, 61.4, 57.6, 43.8, 38.6, 28.1, 21.6, 14.1. MS (ESI) m/z [M ? H]?
Calcd. for C24H24NO7: 438.16; found: 438.28. Anal. Calcd. for C24H23NO7: C, 65.90;
H, 5.30. Found: C, 65.95; H, 5.33.
Ethyl 3,9-dihydroxy-9-methyl-7-phenyl-7,8,10-trihydro-6H-dibenzo[c]pyran-6-one-
8-carboxylate (1c)
1
White solid, mp 245–248 °C. H NMR (300 MHz, DMSO-d6) d (ppm): 10.42 (s,
1H), 7.61 (d, J = 8.7 Hz, 1H), 7.22–7.08 (m, 5H), 6.82 (dd, J = 8.7, 2.1 Hz, 1H),
6.67 (d, J = 2.1 Hz, 1H), 4.70 (s, 1H), 4.27(d, J = 10.5 Hz, 1H), 4.05–3.92 (m,
2H), 3.11 (dd, J = 18.3, 2.1 Hz, 1H), 2.96 (d, J = 18.0 Hz, 1H), 2.76 (d,
J = 10.5 Hz, 1H), 1.33 (s, 3H), 1.05 (t, J = 7.2 Hz, 3H). 13C NMR (75 MHz,
DMSO-d6) d (ppm): 172.0, 160.7, 159.6, 154.3, 147.2, 144.3, 128.4, 128.3, 126.5,
126.3, 120.1, 113.3, 112.4, 102.4, 68.2, 60.2, 60.2, 58.8, 43.0, 40.4, 28.4, 14.6. MS
(ESI) m/z [M ? H]? Calcd. for C23H23O6: 395.15; found: 395.10. Anal. Calcd. for
C23H22O6: C, 70.04; H, 5.62. Found: C, 70.12; H, 5.67.
Ethyl 3,9-dihydroxy-9-methyl-7-(4-nitrophenyl)-6-oxo-7,8,10-trihydro-6H-
benzo[c]chromene-8-carboxylate (1d)
1
White solid, mp 252–254 °C. H NMR (300 MHz, DMSO-d6) d (ppm): 10.47 (s,
1H), 8.08 (d, J = 8.7 Hz, 2H), 7.64 (d, J = 8.7 Hz, 1H), 7.39 (d, J = 8.7 Hz, 2H),
6.82 (dd, J = 8.4, 2.4 Hz, 1H), 6.67 (d, J = 2.4 Hz, 1H), 4.84 (s, 1H), 4.39 (d,
J = 10.5 Hz, 1H), 4.05–3.90 (m, 2H), 3.15 (d, J = 18.6 Hz, 1H), 2.98 (d,
J = 18.6 Hz, 1H), 2.82 (d, J = 11.1 Hz, 1H), 1.34 (s, 3H), 1.03 (t, J = 7.2 Hz,
3H). 13C NMR (75 MHz, DMSO-d6) d (ppm): 171.5, 161.0, 159.7, 154.3, 152.7,
148.4, 146.4, 129.8, 126.5, 123.7, 118.8, 113.5, 112.2, 102.4, 68.1, 60.5, 57.9, 43.0,
40.5, 28.2, 14.5. MS (ESI) m/z [M ? H]? Calcd. for C23H22NO8: 440.13; found:
440.25. Anal. Calcd. for C23H21NO8: C, 62.87; H, 4.82. Found: C, 70.12; H, 5.67.
Ethyl 3,9-dihydroxy-9-methyl-6-oxo-7-(4-methylphenyl)-7,8,10-trihydro-6H-
benzo[c]chromene-8-carboxylate (1e)
1
White solid, mp 247–249 °C. H NMR (300 MHz, DMSO-d6) d (ppm): 10.40 (s,
1H), 7.59 (d, J = 8.7 Hz, 2H), 7.20 (d, J = 7.5 Hz, 1H), 6.97 (d, J = 8.7 Hz, 2H),
7.20 (d, J = 7.5 Hz, 1H), 6.80 (dd, J = 8.4, 2.1 Hz, 1H), 6.66 (s, 1H), 4.67 (s, 1H),
4.23 (d, J = 10.2 Hz, 1H), 4.06–3.89 (m, 2H), 3.08 (d, J = 18.0 Hz, 1H), 2.93 (d,
J = 18.0 Hz, 1H), 2.72 (d, J = 10.5 Hz, 1H), 2.20 (s, 3H), 1.31 (s, 3H), 1.06 (t,
J = 7.2 Hz, 3H). 13C NMR (75 MHz, DMSO-d6) d (ppm): 172.0, 160.6, 159.5,
154.3, 146.9, 141.3, 135.3, 129.0, 128.2, 126.3, 120.3, 113.2, 112.4, 102.3, 68.2,
60.2, 58.8, 42.5, 28.4, 21.1, 14.6. MS (ESI) m/z [M ? H]? Calcd. for C24H25O6:
123