p-Toluenesulfonic acid → HCID 9972023, compound

Participants

Reaction Steps

A catalytic amount of p-toluenesulfonic acid was added to a solution of 2-hydroxy-9-phenyl-7-propyl-3,4-dihydro2H,6H-pyrimido[6,1-b][1,3]thiazine-6,8(7H)-dione (0.5 g) in toluene (20 ml) and was refluxed for 5 hours. The reaction solution was concentrated to dryness, and the resulting residue was dissolved in methylene chloride. After washing with water and drying, the solution was concentrated to dryness. The resulting crude crystals were recrystalized from ethyl acetate-isopropyl ether to give colorless prisms (0.33 g, 70%).

Provenance & Evidence