Patent ID: 6365743
Filing Date: 2002-04-02
Classification: C07D

Abstract:
Method for the preparation of an enantiomerically pure imidazolyl compound I of the formula wherein:n is 0 or 1; m is 1 or 2; R1 is hydrogen, methyl or ethyl; and C* denotes a chiral centre; as the monohydrate of its hydrochloric acid addition salt;a) by adding a pyroglutamic acid in an optically active form to a solution of a racemic mixture of the above compound I, followed by separation of the crystallized acid addition salt of said mixture of enantiomers of compound I enriched in one enantiomer, from the mother liquor enriched in the other enantiomer, b) when the crystallized acid addition salt is enriched in the undesired enantiomer, by then separating the mixture of enantiomers in the mother liquor from said acid, followed by addition of a racemic mixture of said acid to a solution of the obtained mixture of isomers of I, and by separation of the crystallized acid solution addition salt of said mixture, enriched in the desired enantiomer, from the mother liquor, and by; c) optionally recrystallizing the product until the desired enantiomeric purity is obtained, and by then d) converting this acid-addition salt of the desired enantiomer to the desired enantiomerically pure imidazolyl compound I of the formula as its hypochloride monohydrate.