PROCESS FOR PREPARING LEUKOTRIENE ANTAGONISTS

摘要

0055/TR2 17822 TITLE OF THE INVENTION PROCESSES FOR PREPARING LEUKOTRIENE ANTAGONISTS Disclosed is a process for preparing the R and S enantiomers of a compound of the formula; which comprises; (1) reacting an enzyme with a prochiral diester of the formula II 0055/TR2 - i - 17822 where M1 and M2 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: III