Acetic Acid → HCID 22758871, compound

Participants

Reaction Steps

A mixture of ethyl 7-allyl-6,7-dihydro-10-methoxy-4-oxo-4H-pyrimido[2,1-a]isoquinoline-3-carboxylate (1.5 g., 4.41 mmoles) and DDQ (1.1 g., 4.85 mmoles) in toluene (30 ml.) containing acetic acid (0.05 ml.) was refluxed for 18 hours. The mixture was filtered and the filtrate concentrated to dryness. Trituration of the residue with methanol gave a solid which was recrystallized from ethanol to give 201 mgs. of brown crystals, m.p. 182°-186°. The methanol mother liquor was concentrated to dryness and the residue chromatographed on silicic acid with toluene-acetone (20:1) to give additional product (230 mgs.), m.p. 177°-183° after recrystallization from ethanol. The material with m.p. 182°-186° was chromatographed in a similar manner and the product so obtained combined with the material with m.p. 177°-183° and the lot recrystallized from ethanol to give yellow needles of the title compound, m.p. 187°-188°.

Provenance & Evidence