Diphosgene → 5-Methyl-2h-thieno[2,3-d][1,3]oxazine-2,4(1h)-dione

Participants

Reaction Conditions

Reaction Steps

Potassium hydroxide (14.77 g, 0.26 mol) was dissolved in 500 mL water. To this solution was added ethyl 2-amino-4-methyl-thiophene-3-carboxylate (24.38 g, 0.13 mol). The solution was heated at 100° C. for 16 hours. The solution was then cooled to 0° C. and trichloromethyl chloroformate (23.8 mL, 0.20 mol) was added slowly. The solution was allowed to come to room temperature and further stirred for 5 hours. The precipitated solid was collected by vacuum filtration to yield 16.0 g (66%) of 5-methyl-1H-thieno[2,3-d][1,3]oxazine-2,4-dione. MP 220° C. 1H-NMR (DMSO-d6) δ 2.30 (d, J=1.2 Hz, 3H), 6.78 (d, J=1.2 Hz, 1H), 12.55 (b, 1H) ppm; EIMS m/z 184 (M+1).

Provenance & Evidence