PROCESS FOR PREPARING PYRIDAZIN-3-ON DERIVATIVES

摘要

A pyridazin-3-on derivative of formula (1) in which R2 is a hydrogen atom or a C1-C3 alkyl group, R<3> is a hydrogen atom or a C1-C3 alkyl group, and Q is an optionally substituted phenyl group can be prepared at a high yield and high purity by ring closing a carboxylic acid derivative of formula (2) in which R<2>, R<3> and Q are the same as defined above, or its salt in the presence of a nitrogen-containing aromatic compound and a boron compound.