Synthesis of intermediates useful in preparing bromo-substituted tricyclic compounds

摘要

The invention relates to a process for preparing a compound of the formula I comprising: (a) reacting 2,5-dibromo-3-methylpyridine with an amine of the formula NHR5R6 to obtain an amide; (b) reacting the amide with a compound of formula 3 3 in the presence of a strong base to obtain a compound of formula 4 4 (c) converting a compound of formula 4 to the corresponding cyano compound or aldehyde; (d) reacting the cyano compound or aldehyde with a piperidine derivative to obtain an aldehyde or alcohol of formula 7a or 7b, respectively: 7a 7b (e) cyclizing a compound of formula 7a or 7b; wherein R1-R7 are as defined in the specification.