3-(4-Piperidyl)-6-fluoro-1,2-benzisoxazole → 3-{2-[4-(6-Fluorobenzo[d]isoxazol-3-yl)-piperidin-1-yl]-vinyl}-2-methyl-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-4-one

Participants

Reaction Steps

A mixture of 2.96 g (14.33 mmoles) of (2-methyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-3-yl)-acetaldehyde (II), 3.16 g (14.33 mmoles) of 6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole (IV) and 50 mL of toluene was transferred to a Dean Stark apparatus. The mixture was brought to boiling point, refluxed for 3 hours, and the solvent was evaporated under reduced pressure to give 5.70 g (97.3%) of 3-{2-[4-(6-fluorobenzo[d]isoxazol-3-yl)-piperidin-1-yl]-vinyl}-2-methyl-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-4-one (III) as a deep orange solid. The compound thus obtained was pure enough as to be used in the subsequent reaction step with no prior purification or optionally crystallized from an organic solvent, preferably ethanol.

Provenance & Evidence