Patent ID: 7192983

Claim:
A process of stabilizing for storage an N-protected/N-substituted alpha-amino aldehyde comprising: (a) treating said N-protected/N-substituted alpha-amino aldehyde represented by the formula: wherein R 1 represents alkyl, alkenyl, alkyl substituted with one or more aryl radicals, cycloalkenylalkyl, alkanoyl, haloalkanoyl, aroyl, alkoxycarbonyl, aralkoxycarbonyl, heteroaralkoxycarbonyl or 9-phenylfluoren-9-yl radicals; R 2 represents hydrogen, alkyl, alkenyl, aralkyl, cycloalkyl, cycloalkenylalkyl or aryl radicals; or —NR 1 R 2 represents heterocyclo or heteroaryl radicals; and R 3 represents alkyl, haloalkyl, cyanoalkyl, hydroxyalkyl, alkoxyalkyl, aryloxyalkyl, alkylthioalkyl, arylthioalkyl, aryl, aralkyl, heteroaryl, heteroaralkyl, cycloalkyl or cycloalkylalkyl radicals; or R 2 and R 3 together with nitrogen atom and the carbon atom to which they are bonded form a heterocyclo radical; with HSO 3 W, at an equivalence ratio of said N-protected/N-substituted alpha-amino aldehyde to said HSO 3 W from about 1:1 to about 1:10, in a mixture of water and an organic solvent 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, to form a corresponding stable 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 R 1 , R 2 and R 3 are as defined above; and (b) converting said N-protected/N-substituted beta-amino hydroxy sulfonate back to said N-protected/N-substituted alpha-amino aldehyde by (i) treating said 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.