Triethylamine → 3-cyclopropyl-6-ethylthieno[2,3-d]pyrimidine-2,4(1H,3H)-dione

Participants

Reaction Steps

To a solution (40 mL) of methyl 2-amino-5-ethylthiophene-3-carboxylate (0.5 g) in methylene chloride were added triphosgene (0.8 g) and triethylamine (0.6 mL), and the mixture was stirred at room temperature for 2 hr. To the reaction mixture was added cyclopropylamine (1.88 mL), and the mixture was further stirred at room temperature for 1 hr. The reaction mixture was washed with water and saturated brine, and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure. The obtained solid was dissolved in methanol (20 sodium methoxide (28% methanol solution, 0.64 g) was added, and the mixture was stirred at 60° C. for 2 hr. The reaction mixture was neutralized with hydrochloric acid (10% methanol solution), insoluble material was filtered off, and the solvent was evaporated under reduced pressure. The precipitated solid was collected by filtration to give the title compound as a colorless solid (0.28 g, 88%).

Provenance & Evidence