[CH2:1]([C:3]1([CH2:16][CH3:17])[CH2:8][C:7](=[O:9])[C:6]2[CH:10]=[C:11]([C:14]#[N:15])[CH:12]=[CH:13][C:5]=2[O:4]1)[CH3:2].[BH4-].[Na+]>CO.O1CCCC1>[CH2:16]([C:3]1([CH2:1][CH3:2])[CH2:8][CH:7]([OH:9])[C:6]2[CH:10]=[C:11]([C:14]#[N:15])[CH:12]=[CH:13][C:5]=2[O:4]1)[CH3:17]To a solution of 2,2-diethyl-3,4-dihydro-4-oxo-2H-1-benzopyran-6-carbonitrile (2.29 g) in a mixture of methanol (23 ml) and tetrahydrofuran (5 ml) was added sodium borohydride (0.37 g) at ambient temperature. The reaction mixture was stirred for an hour at the same temperature and evaporated in vacuo. The residue was dissolved in ethyl acetate, and then washed with water and brine successively. The extract was dried over anhydrous magnesium sulfate, and evaporated in vacuo. The residue was purified with silica gel column chromatography using a mixture of methanol and methylene chloride (1:20) as an eluent to give 2,2-diethyl-3,4-dihydro-4-hydroxy-2H-1-benzopyran-6-carbonitrile (2.34 g).
Wird geladen…
