Patent ID: 6040443
Filing Date: 2000-03-21
Classification: C07D

Abstract:
A process for the production of a 1,3-benzoxazin-4-one having the formula. ##STR8## in which R.sub.1 and R.sub.2, independently, are hydrogen, cyano, halogen, nitro, C.sub.1 -C.sub.20 alkyl, O--C.sub.1 -C.sub.20 alkyl, phenyl, NH--CO--C.sub.1 -C.sub.20 alkyl, N(R.sub.3).sub.2, SO.sub.2 N(R.sub.3).sub.2, COOR.sub.3 or CON(R.sub.3).sub.2 in which R.sub.3 is hydrogen, cyano, halogen, nitro, C.sub.1 -C.sub.20 alkyl, O--C.sub.1 -C.sub.20 alkyl, phenyl or NH--CO--C.sub.1 -C.sub.20 alkyl, comprising reacting, at elevated temperature, 1 molar equivalent of an o-hydroxybenzamide of the formula: ##STR9## in which R.sub.1 has its previous significance, with 2 to 6 molar equivalents of a benzoyl chloride of the formula: ##STR10## in which R.sub.2 has its previous significance, in which the process is conducted by heating the reaction mixture, in the absence of any external solvent, until a melt is formed, using a molar ratio of the reactant of formula (3) to the reactant of formula (2) ranging from 2.01:1 to 4:1.