Process for the production of optically active amino alcohols

摘要

Preparation of optically active cyclic amino alcohols or their salts involves reacting an optically active hydroxycarboxylate with hydrazine to form hydroxycarboxylic hydrazide followed by its Curtius reaction with an alcohol to form alkoxycarbonylamino alcohol, and deprotection of amino group. Preparation of optically active cyclic amino alcohols or their salts of formula (I) involves: (1) reacting an optically active hydroxycarboxylate of formula (IV) with hydrazine to give hydroxycarboxylic hydrazide (III); and (2) Curtius reaction of (III) with alcohol of formula R 6>OH to form alkoxycarbonylamino alcohol (II) followed by deprotecting the amino group to give (I). [Image] R 1>1-6C alkyl; R 2>-R 5>H, lower alkyl or optionally substituted phenyl; A 1>-(CH 2) m-; A 2>-(CH 2) n-; m and n : 0-3; m+n : 1-3; R 6>1-6C alkyl or optionally substituted benzyl. R 2> and R 4>, R 2> and R 5>, R 3> and R 4> or R 3> and R 5> taken together with the carbon atoms to which they are attached optionally form an optionally fused ring. The relative configuration of hydroxyl group to alkoxycarbonyl, hydrazinocarbonyl, alkoxycarbonylamino or amino group on each of the asymmetric carbons is trans.