Patent ID: 6586627
Filing Date: 2003-07-01
Classification: C07C,C07D

Abstract:
A process of stabilizing for storage an N-protected/N-substituted alpha-amino aldehyde comprising:(a) treating the N-protected/N-substituted alpha-amino aldehyde represented by the formula: â€ƒwherein R1 represents alkyl, alkenyl, alkyl substituted with one or more aryl radicals, cycloalkenylalkyl, alkanoyl, haloalkanoyl, aroyl, alkoxycarbonyl, aralkoxycarbonyl, heteroaralkoxycarbonyl or 9-phenylfluoren-9-yl radicals; R2 represents hydrogen, alkyl, alkenyl, aralkyl, cycloalkyl, cycloalkenylalkyl or aryl radicals; or âˆ’NR1R2 represents heterocyclo or heteroaryl radicals; and R3 represents alkyl, haloalkyl, cyanoalkyl, hydroxyalkyl, alkoxyalkyl, aryloxyalkyl, alkylthioalkyl, arylthioalkyl, aryl, aralkyl, heteroaryl, heteroaralkyl, cycloalkyl or cycloalkylalkyl radicals; or R2 and R3 together with nitrogen atom and the carbon atom to which they are bonded form a heterocyclo radical; with HSO3W at an equivalence ratio of about 1:1 to about 1:10 in a mixture of water and an organic solvent to form a corresponding stable N-protected/N-substituted beta-amino hydroxy sulfonate; wherein the organic solvent is selected from the group consisting of ethyl acetate, tetrahydrofuran, isopropyl acetate, methyl isobutyl ketone, methyl ethyl ketone, acetone, dimethoxyethane, dimethoxymethane, dioxane, and methyl tert-butylether; the N-protected/N-substituted beta-amino hydroxy sulfonate represented by the formula: wherein W represents a cation which is capable of forming a sulfate salt; and R1, R2 and R3 are as defined above; and (b) converting the N-protected/N-substituted beta-amino hydroxy sulfonate back to the N-protected/N-substituted alpha-amino aldehyde by (i) treating the N-protected/N-substituted beta-amino hydroxy sulfonate with an aqueous base solution at a pH of between about 7.5 to about 10 and (ii) extracting with an organic solvent.