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

Participants

Reaction Conditions

Reaction Steps

40 g (250 mmol) 3-Amino-thiophene-2-carboxylic acid methyl ester were suspended in 250 ml water with 21.0 g (374 mmol) potassium hydroxide. The mixture was boiled in a microwave oven (500 W) for 30 min and afterwards it was cooled to 0° C. A solution of 37.1 g (125 mmol) triphosgene in 200 ml toluene was added drop wise and the reaction mixture stirred for 2 h at room temperature. The residue was isolated by filtration. The product was washed with water and sodium bicarbonate solution. For further purification it can be washed with ethyl ether and methanol after drying.

Provenance & Evidence