Patent attributes
A process for the preparation of compound of formula (I); wherein R1 is hydrogen, linear, branched or cyclic lower alkyl, cyclohexyl, allyl, propargyl or benzyl; R2 is hydrogen, methyl, ethyl or propyl; or R1 and R2 together with the nitogen to which they are attached form a cyclic moiety of three to eight-membered ring, with or without a hetero atom like nitrogen or oxygen; R3 is hydrogen or lower alkyl; R4 and R5 are the same or different and each is a lower alkyl; comprising reacting compound of formula (II); wherein R3, R4 and R5 are as defined above, with compound of formula (III); wherein R1 and R2 are as defined above, in the presence of a base, and further resolving the compound of formula (I) to obtain (S)-isomer of compound of formula (I), substantially free of R-isomer
