Patent ID: 8859765

Claim:
A process for preparing a compound of formula (I) the process comprising: i) contacting a sulfonamide of formula (II) with a first reducing agent under conditions sufficient to provide a disulfide compound of formula (III) and ii) contacting the disulfide compound of formula (III) with a second reducing agent under conditions suitable to form a compound of formula (I); wherein R 1 and R 2 are independently H, benzyl, substituted benzyl, C 1-12 alkyl, C 3-10 cycloalkyl, C 4-9 heterocycloalkyl, C 6-10 aryl, or C 5-9 heteroaryl; R 3 and R 4 are independently H, benzyl, substituted benzyl, C 1-12 alkyl, C 3-10 cycloalkyl, C 4-9 heterocycloalkyl, C 6-10 aryl, or C 5-9 heteroaryl; or optionally R 3 , R 4 , and N can together form a C 3-10 heterocycle.