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

Participants

Reaction Conditions

Reaction Steps

Methyl 3-aminothiophene-2-carboxylate (4.9 g, 31.3 mmol) and urea (19 g, 187 mmol) were dissolved in N,N-dimethylformamide (10 mL), the reaction temperature was raised to 190° C., followed by stirring for 12 hours. After the reaction was complete, the reaction mixture was added to 1N NaOH aqueous solution, cooled to room temperature and filtered under a reduced pressure to remove the insoluble precipitate. The filtrate was acidified (pH 2) with 2N HCl aqueous solution, and the resulting solid was filtered under a reduced pressure with washing using distilled water. The resulting solid was dried under a reduced pressure to obtain the title compound (yield: 3.2 g, 61.5%).

Provenance & Evidence