Phosphoric Acid → (3-cyano-1H-indol-7-yl)-[4-(4-fluorophenethyl)piperazin-1-yl]-methanone phosphate hydrate

Participants

Reaction Conditions

Reaction Steps

Add (3-cyano-1H-indol-7-yl)-[4-(4-fluorophenethyl)piperazin-1-yl]methanone (12.00 g 31.9 mmol) and acetone (300 mL) to a 500 mL flask equipped with overhead agitation, heating mantle, and condenser. Heat the slurry to about 55° C. to provide a homogeneous solution. Add a solution of concentrated (86% by weight) phosphoric acid (4.00 g, 35.1 mmol, 1.1 equiv) over 1 minute. The salt may begin to precipitate after approximately half of the phosphoric acid is added. After the addition is complete, heat the mixture to about 55° C. for 2 hours. Remove the heating mantle and allow the slurry to cool to about 22° C. and then stir for 2 hours. Filter the mixture and wash the filter cake twice with 30 mL acetone. Dry the solid for 20 hours in a vacuum oven at about 50° C. to provide 14.15 g (93% yield) of the title crystal form as a white solid. Initially, this process may produce a precipitate that may be gummy, but may become granular upon further stirring.

Provenance & Evidence