| 摘要 |
PURPOSE:To obtain the titled compound useful as a synthetic intermediate for 3-unsubstituted cephalosporin, in high yield, by reducing 3-oxocepham-4- carboxylic acid aralkyl ester, etc. with alkali metal borohydride under specific condition. CONSTITUTION:The objective 3xsi-hydroxycephem-4-carboxylic acid aralkyl ester can be produced by (1) dissolving preferably 7-amido-3-oxocepham-4-carboxylic acid aralkyl ester or its enol compound in 3-30pts.vol of a mixture of prefer ably a halohydrocarbon and an anhydrous lower alkanol or N,N- dialkylalkanamide, (2) cooling the solution to <=-20 deg.C, especially to -30--80 deg.C, and (3) adding 1-20 equivalent, especially 1-5 equivalent of an alkali metal borohydride to the solution and reacting for 10min-20hr, espe cially for 30min-10hr.
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