反应详情

To a solution of 6-(2,2,2-trichloro-acetyl)-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazine-8-carboxylic acid ethyl ester (Comp. No. 4a) (11 g, 32.3 mmol) in tetrahydrofuran (60 ml) was added water (110 ml) and potassium hydroxide (1.72 g, 30.7 mmol). The mixture was stirred for 5 min, then an additional portion of potassium hydroxide (250 mg) was added and the mixture was stirred for 2 h at 25° C. Tetrahydrofuran was evaporated in vacuo. After addition of 50 ml water, the mixture was acidified with 10 M aqueous hydrochloric acid. The precipitate was filtered off, washed with a small portion of water and dried in vacuo at 55° C. to give 6.56 g (85%) of 3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazine-6,8-dicarboxylic acid 8-ethyl ester as a white solid. LC/MS (method 3): Rt=1.34 min; m/z=240.03 (M+H+).

1. stirringthe mixture was stirred for 2 h at 25° C
2. customTetrahydrofuran was evaporated in vacuo
3. additionAfter addition of 50 ml water
4. filtrationThe precipitate was filtered off
5. washwashed with a small portion of water
6. customdried in vacuo at 55° C.