Process for the production of 7.beta.-substituted 3-hydroxycepham-4-carboxylic acid compounds of the formula ##STR1## in which R.sub.1.sup.a represents hydrogen or an amino-protecting group R.sub.1.sup.A, and R.sub.1.sup.b represents hydrogen or an acyl radical Ac, or in which R.sub.1.sup.a and R.sub.1.sup.b together form a bivalent amino-protecting group, and R.sub.2 represents a radical that, together with the carbonyl grouping --C(.dbd.O)--, forms a protected carboxyl group, and 1-oxides thereof as well as salts of such compounds with salt-forming groups, from a 7.beta.-substituted 3-hydroxy-3-cephem-4-carboxylic acid compound of the formula ##STR2## from a 1-oxide or a salt thereof, and a complex borohydride, characterized in that the reduction is carried out in the presence of an organic acid. The reduction in the presence of an organic acid produces higher yields.
生产7.beta.-取代的
3-羟基头孢烷-4-
羧酸化合物的过程,其
化学式为##STR1## 其中R.sub.1.sup.a代表氢或
氨基保护基R.sub.1.sup.A,R.sub.1.sup.b代表氢或酰基Ac,或者R.sub.1.sup.a和R.sub.1.sup.b一起形成一个二价
氨基保护基,R.sub.2代表与羰基团--C(.dbd.O)--一起形成保护羧基的基团,以及其1-氧化物和带有盐基团的盐。该过程从式##STR2## 的7.beta.-取代的3-羟基-3-头孢烷-4-
羧酸化合物的1-氧化物或其盐,以及一个复杂
硼氢化物中进行,其特征在于还需在有机酸的存在下进行还原反应。在有机酸的存在下进行还原反应能提高产率。