Process for the manufacturing of pharmaceutically active 3,1-benzoxazine-2-ones

摘要

A process for making a compound of formula 1 or a salt thereof, wherein: R¹ and R² are each independently H, halogen, or C_1-4-alkyl, or R¹ and R² together are C_1-6-alkylene; and R³ is H, halogen, OH, C_1-4-alkyl, or O-C_1-4-alkyl, the process comprising: (a) reacting a compound of formula 6 wherein R⁴ is benzyl, diphenylmethyl, or trityl, each optionally substituted at, if available, an aryl group or an aliphatic carbon atom, with a compound of formula 7 or a salt thereof, to obtain a compound of formula 5, or a salt thereof (b) reducing the nitro group of the compound of formula 5 to an amine group and mesylating this amine group and cleaving the protecting group during the reduction step or after the mesylation step to obtain the compound of formula 1.