Method of preparing vicinal aminoalcohols

Method for the preparation of an N-substituted vicinal aminoalcohol derivative of formula 1 ##STR10## wherein D is a group protecting the hydroxy group;

• R.sub.1 is optionally selected from the group consisting of phenyl, naphthyl, benzofuryl, benzodioxanyl and benzodioxolyl which is substituted with one or more groups X, wherein X is hydroxy, alkoxy(1-5C), alkyl(1-5C)carbonyloxy, amino, alkyl(1-5C)carbonylamino, alkyl(1-5C)sulphonylamino, nitro, alkyl(1-5C)sulphonyl, alkyl(1-5C)carbonyl, halogen, cyano, alkyl(1-5C) or cycloalkyl(5-12C), or wherein R.sub.1 is a saturated or unsaturated straight or branched alkyl group having 1-30 C-atoms which may be substituted with halogen, alkoxy(1-5C), alkylthio(1-5C), phenyl or phenoxy optionally substituted with one or more groups X, and
• R.sub.2 is a hydrogen atom or a saturated or unsaturated straight or branched alkyl(1-10C) group, optionally substituted with halogen, hydroxy, alkoxy(1-4C) or OD, or a phenyl, phenylalkyl(7-10C) or heteroarylalkyl(1-3C for the alkyl) group, wherein the heteroaryl is selected from the group consisting of benzofuryl, benzodioxanyl and benzodioxolyl, optionally substituted with one to three groups X, or wherein R.sub.2 has the formula 7 ##STR11## wherein R.sub.3 is hydrogen or alkyl(1-4C);
• is prepared by reacting a hydroxy-protecting cyanohydrin derivative of formula 2 ##STR12## with a reducing reagent of formula 3
• (R).sub.m --A--H (3)
• wherein
• A represents a hydrogen atom or a metal atom selected from the group consisting of alkali, earth alkali or early transition metal atoms,
• R is an alkyl(1-6C), alkoxyalkyl(1-6C) or alkoxyl(1-6C) group, and
• m is, dependent on the valence of A, 0-2;
• yielding a partially reduced compound of formula (4) ##STR13## followed by a transimination reaction using a primary amine of formula 5
• R.sub.2 --NH.sub.2 ( 5)
• and reduction of the resulting imine, wherein D, R.sub.1 and R.sub.2 have the abovementioned meanings;
• with the proviso that, if R.sub.2 is a hydrogen atom, the transimination reaction step is omitted.