Process for preparing tricyclic compounds having antihistaminic activity

Abstract

Disclosed is a process for preparing a compound having the formula: wherein R1 is selected from the group consisting of: alkyl, alkenyl, alkynyl, aryl, aralkyl, cycloalkyl, and cycloalkylalkyl, R1 being optionally substituted by substituents selected from halo, —OH, alkyl, alkoxy, or —CF3, said process comprising the following steps: (a) reacting a ketone having the formula with a carbanion having the formula wherein R1 is as defined above, and R2 and R3 are independently selected from the group consisting of —ORA and —RA, wherein RA is alkyl, phenyl, substituted phenyl, cycloalkyl, substituted cycloalkyl, cycloalkylalkyl, or substituted cycloalkylalkyl; (b) treating the reaction mixture from step (a) with a protonating agent; and (c) thermally decomposing the product of 16, to form the compound of formula (I). The compounds made by this process have antihistaminic activity, e.g., loratadine. Also disclosed are novel intermediates having the formula wherein R1, R2 and R3 are as defined above.

Dependencies are inferred from the claim text.