Patent ID: 6894164
Filing Date: 2005-05-17
Classification: C07D

Abstract:
1. A process for preparing phthalazines of formula and salts thereof wherein Py represents a 2, 3 or 4-pyridinyl group optionally substituted by one or more substituents selected from halogen, nitro, cyano, oxo and carboxy: R and R1, which may be the same or different between them, represent hydrogen, C Y represents two hydrogen atoms or a group ═O when W is absent when a) hydrogen; b) (C c) —COR or (C 1 -C 4 )-alkyl optionally substituted by a heterocycle; d) (C which comprises the preparation of an intermediate of formula I  wherein R, R wherein said process comprises reacting a compound of formula II  wherein R and R wherein Py has the above reported meaning; by heating of the mixture of the compounds of formula II and III in the presence of an anhydride and optionally in admixture with a suitable solvent, to form the intermediate of formula I and subsequently reacting the intermediate of formula I with hydrazine monohydrate to form a phthalazine of formula IV.