Methyl 3-amino-2-thiophenecarboxylate → Thieno(3,2-d)pyrimidine-2,4(1H,3H)-dione

Participants

Reaction Steps

To a solution in which sodium cyanate (5.0 g, 77.0 mmol) was dissolved in water (15.0 mL), methyl 3-aminothiophen-2-carboxylate (6.05 g, 38.4 mmol) dissolved in a mixture solution (90 mL) of 50% glacial acetic acid and water was slowly added dropwise. After stirring for 5 hours at room temperature, thus prepared white precipitate was filtered. The white solid was dissolved in 2.0 N sodium hydroxide solution (90.0 mL). The mixture solution was cooled to 0° C. and acidified using acetic acid. Filtration of thus prepared white solid followed by drying yielded the target compound thieno[3,2-d]pyrimidin-2,4(1H,3H)-dione (5.2 g, 81% yield).

Provenance & Evidence