反应详情

A method for the preparation of 7,8-difluoro-2,3-dihydro-3-methyl-4H-1,4-benzoxazine either as the optically active s-(-)-7,8-difluoro-2,3-dihydro-3-methyl-4H-1,4-benzoxazine or the racemic mixture. The process of the invention comprises the reaction of 2,3,4-trifluoroaniline or trifluoronitrobenzene with hydroxyacetone or a hydroxyacetone derivative under reducing condition to yield N-(3-hydroxy-2-propyl)-2,3,4-trifluoroaniline derivative. The N-(3-hydroxy-2-propyl)-2,3,4-trifluoroaniline is treated with base to yield the benzoxazine intermediate.