Hydrochloric Acid → 6,7-Dihydro-4-oxo-4H-pyrimido[2,1-a]isoquinoline-3-carboxylic Acid

Participants

Reaction Steps

A mixture of ethyl 6,7-dihydro-4-oxo-4H-pyrimido[2,1-a]isoquinoline-3-carboxylate (1.81 g., 6.7 mmoles), 1.0 N NaOH (25 ml.) and 95% ethanol was refluxed for 20 l minutes. The resulting solution was cooled and acidified with 1.0 HCl (26 ml.) to precipitate the acid, which was crystallized from 2-methoxyethanol to give colorless crystals: 1.02 g. (63% yield), m.p. 215°-217°. An additional recrystallization from 2-methoxyethanol gave material with m.p. 215.5°-217°.

Provenance & Evidence