反应详情

A solution of 4.5 g of 6-chloro-3,4-dihydro-3-oxo-2H-1,4-benzoxazine-8-carboxylic acid in 100 ml of tetrahydrofuran and 10 ml of dimethylformamide is cooled to below 0° C. and 2.5 ml of triethylamine is added under stirring thereto. Further, 2.4 g of ethyl chlorocarbonate is added and the mixture is stirred while keeping below 50° C. for an hour. To the resultant mixture is added 3.6 g of 3-amino-1benzylpiperidine and the mixture stirred for 4 hours. After completion of the reaction, aqueous sodium hydrogen carbonate and ethyl acetate are added. The organic layer is separated, washed with water and dried over magnesium sulfate. The solvent is distilled off and the residue is recrystallized from ethanol-ethyl acetate to give N-(1-benzyl-4-piperidyl) -6-chloro-3,4-dihydro-3-oxo-2H-1,4-benzoxazine-8-carboxamide, melting at 203°-206° C.

1. stirringthe mixture is stirred
2. waitwhile keeping below 50° C. for an hour
3. stirringthe mixture stirred for 4 hours
4. additionare added
5. customThe organic layer is separated
6. washwashed with water
7. dry with materialdried over magnesium sulfate
8. distillationThe solvent is distilled off
9. customthe residue is recrystallized from ethanol-ethyl acetate