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(d, 1H, J ¼ 10.2 Hz), 3.94 (t, 1H, J ¼ 10.2 Hz), 3.81 (s, 6H), 3.51–3.60 (m, 1H), 2.89
(dd, 1H, J ¼ 11.4 and 15.0 Hz), 2.76 (dd, 1H, J ¼ 15.6 and 3.6 Hz), 1.39 (s, 6H); 13C
NMR (CDCl3, 125 MHz): d 159.64, 158.24, 155.01, 152.29, 128.30, 127.51, 126.92,
121.92, 121.85, 114.79, 114.56, 104.18, 104.06, 98.66, 75.99, 70.11, 55.34, 31.55,
30.34, 27.91; ESI-MS: m=z (%) ¼ 353 (100) [M þ Hþ]. Anal. calcd. for C22H24O4:
C, 74.98; H, 6.86. Found: C, 74.88; H, 6.92.
Compound 9
1
Yield: 78%. Mp: 137–139 ꢂC. Rf 0.39 (6:1 hex–EtOAc). H NMR (CDCl3,
600 MHz): d 7.79 (d, 1H, J ¼ 9.0 Hz), 7.00 (d, 1H, J ¼ 8.4 Hz), 6.62 (d, 1H, J ¼
10.2 Hz), 6.45–6.49 (m, 3H), 5.59 (d, 1H, J ¼ 10.2 Hz), 4.58 (t, 1H, J ¼ 11.4 Hz),
4.52 (dd, 1H, J ¼ 11.4 and 5.4 Hz), 4.24 (dd, 1H, J ¼ 11.4 and 5.4 Hz), 3.83 (s,
3H), 3.77 (s, 3H), 1.47 (s, 3H), 1.44 (s, 3H); 13C NMR (CDCl3, 125 MHz): d
191.55, 160.46, 159.13, 158.43, 157.95, 130.69, 128.74, 128.49, 116.02, 115.80,
115.46, 110.88, 109.18, 104.59, 99.09, 77.40, 71.24, 55.49, 53.36, 47.18, 28.37,
28.01; ESI-MS: m=z (%) ¼ 367 (100) [M þ Hþ].
Compound 10
1
Yield: 5.3%. Mp: 153–154 ꢂC. Rf 0.32 (6:1 hex–EtOAc). H NMR (CDCl3,
600 MHz): d 7.62 (s, 1H), 7.00 (d, 1H, J ¼ 7.8 Hz), 6.49 (s, 1H), 6.46 (d, 1H, J ¼ 7.8 Hz),
6.32–6.35 (m, 2H), 5.59 (d, 1H, J ¼ 9.6 Hz), 4.55 (t, 1H, J ¼ 10.8 Hz), 4.46 (dd, 1H,
J ¼ 10.8 and 4.8 Hz), 4.23 (dd, 1H, J ¼ 10.8 and 4.8 Hz), 3.79 (s, 3H), 3.76 (s, 3H),
1.45 (s, 6H); 13C NMR (CDCl3, 125 MHz): d 191.57, 163.49, 160.46, 159.86, 158.40,
130.66, 129.34, 125.41, 121.28, 116.06, 115.90, 114.54, 104.58, 104.07, 99.11, 77.79,
71.12, 55.48, 55.36, 47.34, 28.54, 28.52; ESI-MS: m=z (%) ¼ 367 (100) [M þ Hþ]; Anal.
calcd. for C22H224O5: C, 72.12; H, 6.05. Found: C, 72.06; H, 6.14.
3-(2,4-Dimethoxyphenyl)-7-hydroxychroman-4-one (8)
Raney nickel (5.8 g, 0.1 mol) was added to a solution of 4 (2.98g, 0.01mol) in
DMF (100mL). The reaction mixture was further stirred at room temperature for
30min under a hydrogen atmosphere. The mixture was filtrated, and the filtrate was
concentrated in vacuo. The residue was recrystallized from EtOAc at ꢃ5 ꢂC to give pure
8 (2.73 g, 91% yield). Mp: 181–183 ꢂC. Rf 0.31 (2:1 hex–EtOAc). 1H NMR (DMSO-d6,
600 MHz): d 10.57 (s, 1H), 7.69 (d, 1H, J ¼ 8.4 Hz), 6.69 (d, 1H, J ¼ 8.4 Hz), 6.59 (d, 1H,
J ¼ 2.4 Hz), 6.53 (dt, 1H, J ¼ 8.4 and 1.2 Hz), 6.48 (dd, 1H, J ¼ 8.4 and 2.4 Hz), 6.35 (m,
1H), 4.53 (t, 1H, J ¼ 10.8 Hz), 4.42 (dd, 1H, J ¼ 10.8 and 5.4 Hz), 4.16 (dd, 1H, J ¼ 10.8
and 5.4 Hz), 3.75 (s, 3H), 3.72 (s, 3H); 13C NMR (DMSO-d6, 125 MHz): d 190.8, 164.8,
163.7, 160.4, 158.6, 131.1, 129.4, 116.5, 114.5, 111.0, 105.3, 102.8, 99.2, 70.8, 56.0, 55.6,
47.1; ESI-MS: m=z (%) ¼ 323 (100) [Mþ Naþ].
2’,4’-Dimethylglabridin (6)
A solution of 9 (3.66 g, 0.01 mol) in ether (40 mL) was added dropwise to a sol-
ution of LiAlH4 (3.8 g, 0.1 mol) in ether (150 mL) at 20 ꢂC and then the mixture was