反应详情

A mixture of 5-hydroxy-6-(1-hydroxypropyl)-2,2-dimethyl-10-propyl-2H-pyrano[2,3-f]chromen-8-one (11a) (400 mg, 1.16 mmol) and platinum oxide poisoned with ammonia (100 mg) in toluene (50 mL) was hydrogenated under atmospheric pressure of hydrogen at ambient temperature for 2 hours. Column chromatography on silica gel eluted with 30% ethyl acetate in hexanes and subsequent crystallization from 20% acetone in hexanes provided 252 mg of 12a (63% yield). 1H NMR (CDCl3): 1.02 (t, J=7.5 Hz, 3H), 1.22 (t, J=7.5 Hz, 3H), 1.41 (s, 6H), 1.62 (m, 2H), 1.82 (t, J=6.5 Hz, 2H), 2.75 (t, J=6.5 Hz, 2H), 2.91 (m, 4H), 3.78 (s, 3H), 6.01 (s, 1H); 13C NMR (CDCl3): 7.97, 13.84, 17.20, 23.19, 26.66, 31.33, 38.48, 38.99, 62.14, 76.35, 106.14, 110.66, 112.48, 116.55, 151.24, 153.50, 157.51, 157.92, 159.92, 203.40; IR: 1724, 1704 cm−1; MS (ACPI+): 359 (M+1); Anal. Calcd. for C21H26O5: C 70.37, H 7.31; Found: C 70.15, H 7.28.

1. washColumn chromatography on silica gel eluted with 30% ethyl acetate in hexanes and subsequent crystallization from 20% acetone in hexanes