Urea → Thieno(3,2-d)pyrimidine-2,4(1H,3H)-dione

Participants

Reaction Conditions

Reaction Steps

A mixture of methyl 3-amino-2-thiophenecarboxylate (13.48 g, 85.85 mmol) and urea (29.75 g, 5 eq.) was heated at 190° C. for 2 hours. The hot reaction mixture was then poured onto sodium hydroxide solution and any insoluble material removed by filtration. The mixture was then acidified (HCl, 2N) to yield 1H-thieno[3,2-d]pyrimidine-2,4-dione (63) as a white precipitate, which was collected by filtration and air dried (9.49 g, 66%).

Provenance & Evidence