Sibopirdine

Sibopirdine, also known as EXP921, is a nootropic drug.

Synthesis

Patent:
4,5-Diazafluoren-9-one is condensed with 4 molar equivalents of 4-picoline in the presence of 2 equivalents of acetic anhydride and acetic acid. The intermediate from this step may originally be a tertiary alcohol which then dehydrates under the reaction conditions to give . The olefin can then be reduced either by catalytic hydrogenation over 5% Pd/C or by sodium borohydride in alcohol to give . Alkylation with 4-picolyl chloride in the presence of sodium hydroxide completed the synthesis of sibopirdine.