Process for the production of phthalazineacetic acid ester derivatives and a novel intermediate

Abstract

This invention relates to a process for the production of phthalazineacetic acid ester derivatives of the formula ##STR1## wherein R is (C.sub.1 -C.sub.4) alkyl which comprises reacting (Z)-3-oxo-1(3H)-isobenzofuranylideneacetic acid with hydrazine in the presence of a solvent; reacting the resulting mixture of the novel compound 1-hydrazino-1,2,3,4-tetrahydro-4-oxo-phthalazineacetic acid and 3,4-dihydro-4-oxo-phthalazineacetic acid with acid in the presence of a solvent; and reacting the resulting 3,4-dihydro-4-oxo-phthalazineacetic acid with acid in the presence of an alcohol. This invention also relates to the novel compound 1-hydrazino-1,2,3,4-tetrahydro-4-oxo-phthalazineacetic acid of the formula ##STR2## which is an intermediate formed in the process of this invention and which is useful for the production of phthalazineacetic acid ester derivatives of formula IV. The compounds of formula IV are useful for the preparation of certain heterocyclic oxophthalazinyl acetic acids and esters thereof.

Dependencies are inferred from the claim text.