Patent ID: 7692015

Claim:
A method for producing (S,S)-2,8-diazabicyclo[4.3.0]nonane of formula I-a and its enantiomer (R,R)-2,8-diazabicyclo[4.3.0]nonane of formula I-b which process comprises: (a). N-alkylation of formula VI where X is selected from Cl, Br and I at each occurrence, with substituted sulfonamide to form an intermediate of formula X where R is C 1 -C 5 alkyl, phenyl, substituted phenyl, tolyl, substituted tolyl, benzyl, or substituted benzyl; (b). reducing the intermediate of formula X by catalytic hydrogenation to give formula XI (c). resolution of formula XI with enantiomerically pure carboxylic acid or sulphonic acid followed by basifying to result in formula XII-a and its enanatiomer XII-b (d). cleaving the N-sulfonyl bond of formula XII-a or formula XII-b to give the title product of formula I-a or I-b