The invention relates to a novel advantageous process for the production of compounds of the formula ##STR1## wherein n is 1, R.sub.1.sup.a is hydrogen or an amino protective group R.sub.1.sup.A, R.sub.1.sup.b is hydrogen or an acyl group Ac, or R.sub.1.sup.a and R.sub.1.sup.b together are a bivalent amino protective group, R.sub.2 is hydroxyl or a radical which, together with the carbonyl grouping --C(.dbd.O)--, forms a protected carboxyl group, and the group of the formula --N(R.sub.3.sup.a) (R.sub.3.sup.b) is a secondary or tertiary amino group, or a salt thereof with salt-forming groups. The process comprises reaction of the corresponding 3-amino compounds with borohydrides in the presence of acids.
本发明涉及一种新的有利的方法,用于制备式为##STR1##其中n为1,R1a为氢或
氨基保护基R1A,R1b为氢或酰基Ac,或R1a和R1b一起为二价
氨基保护基,R2为羟基或与羰基团--C(.dbd.O)--一起形成受保护的羧基基团的基团,并且式为--N(R3a)(R3b)的基团为二级或三级
氨基基团,或其与形成盐的基团的盐。该过程包括在酸的存在下将相应的3-
氨基化合物与
硼氢化物反应。