Potassium Hydroxide → 1H,2H,4H-thieno(3,2-d)(1,3)oxazine-2,4-dione

Participants

Reaction Conditions

Reaction Steps

To a solution of methyl 3-aminothiophene-2-carboxylate 20.0 g (0.127 mol) in water 150 ml was added the aqueous solution of potassium hydroxide 10.7 g (0.191 mol). The resulting solution wad heated to 90° C. for 2 hrs. After being checked by TLC till the starting material was consumed, the reaction solution was cooled to 0° C. Then a solution of triphosgene 18.9 g (0.064 mol) in toluene 150 ml was added dropwise. The resulting solution was stirred at room temperature for 2 hrs. The residue was filtered, and the solid was recrystallized from tetrahydrofuran to obtain 1H-thieno[3,2-d][1,3]oxazine-2,4-dione 8.5 g (yield 40%).

Provenance & Evidence