Method for the preparation of substituted 1,4-dihydro-4-oxo-cinnoline-3-carboxylic acid, esters and salts thereof, and intermediates used in their preparation

摘要

A method for the preparation of compounds of the formula <IMAGE> (I) wherein X represents a group of the formula OR1 or NR1R2, wherein R1 and R2 independently represent H or an organic group that forms a stable covalent bond with the N or O of said X; Y is H or an organic group that forms a stable ester with the adjacent COO group; R is an alkyl or aryl group optionally substituted with one or more stable organic substituents; each R3 independently represents a stable organic group; and n is an integer from 0 to 3; the method using new intermediates of the formula <IMAGE> (VI) wherein R3 and Y have the foregoing meanings; W is either F or Cl; and R9 is a hydrocarbon such as a C1-C4 alkyl or alkenyl group.