Process for preparing leukotriene antagonists.

摘要

Disclosed is a process for preparing the R and S enantiomers of a compound of the formula; <CHEM> which comprises; (1) reacting an enzyme with a prochiral diester of the formula <CHEM> where M<1> and M<2> are the same, to produce a chiral monoester of the compound of formula II; (2) treating the chiral monoester product of step (1) with an amine and a trialkyl aluminum compound to produce the R enantiomer of the compound of formula I; or reacting the chiral monoester product of step (1) with an acid activating agent, an amine, and a base to produce the S enantiomer of the compound of formula I. In the alternative the R enantiomer of the compound of formula I may be synthesized by direct enzymatic hydrolysis of the racemic mixture of a compound having the formula <CHEM> f