Process for preparing chiral dipeptidyl peptidase-IV inhibitors

摘要

A process for the preparation of pyrazolopyrolidines of structural formula I: and W is or P, wherein in P is an amine protecting group. These compounds are useful in the synthesis of dipeptidyl peptidase-IV inhibitors for the treatment of Type 2 diabetes. Also provided are useful intermediates obtained from the process.;

主权项

1. A process for preparing a compound of structural formula I: wherein R2 is selected from the group consisting of:
C1-6 alkyl and C3-6 cycloalkyl; and W is hydrogen; P, wherein P is an amine protecting group; or wherein R3 is hydrogen or P, wherein P is an amine protecting group; comprising sulfonylation of a compound of formula III:  and isomerization of a mixture of compounds of formula I′ and formula I: wherein the sulfonylation of a compound of formula III and isomerization of the sulfonylated formula III comprises mixing a compound of formula III with a sulfonylating agent and at least one base in at least one suitable organic solvent.