PROCESS FOR THE MANUFACTURE OF A TRICYCLIC COMPOUND

摘要

A process for preparing a compound of formula (I) or a phamaceutically-acceptable salt thereof, comprising: 1) reacting a compound of formula (III), in which R is a straight or branched chain alkyl having from one to four carbon atoms, with an alkali metal hydroxide in an aqueous medium at a temperature of about 80 to 120 DEG C and a time of about 20 to 100 hours to form a reaction product; 2) cyclizing the reaction product of step 1) with formic acid and formaldehyde to form a formiate compound; and 3) neutralizing the formiate compound of step 2) with an aqueous base.