| abstract |
A pyridazin-3-on derivative of formula (1) in which R2 is a hydrogen atom or a C1-C3 alkyl group, R3 is a hydrogen atom or a C¿1?-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, R3¿ and Q are the same as defined above, or its salt in the presence of a nitrogen-containing aromatic compound and a boron compound. |