Patent ID: 7053240

Claim:
A process of making a disulfide compound of Formula II: R 5 —S—S—R 2 ; (II) wherein: R 5 is -lower alkyl or -lower alkyl-R 6 ; R 2 is -lower alkyl-R 4 ; R 4 and R 6 are each individually —SO 3 M, —PO 3 M 2 or —CO 2 M; and M is an alkali metal; the process comprising (a) halogenating a starting material having a Formula III: R 2 —Y (III) wherein: Y is a displaceable group displaceable by a S N 2 nucleophilic substitution reaction; to form a first intermediate having a Formula (IV): R 2 -A; (IV) wherein: A is a halogen; (b) reacting the first intermediate with an alkali metal mecaptan having a base-sensitive labile protective group to form a second intermediate having a Formula (V): R 2 —S-Z; (V) wherein: Z is a base-sensitive labile protective group; (c) reacting the second intermediate with a strong base to form a third intermediate having a Formula (VI): R 2 —SH; (VI) (d) oxidizing the third intermediate to form the disulfide compound of Formula II; and (e) isolating the compound of Formula II.