| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject compound in industrially satisfactory yield and purity by cyclization reaction of a carboxylic acid derivative in the presence of a nitrogen-contg. aromatic compound and a boron compound. SOLUTION: This compound of formula IV is obtained by cyclization reaction of a carboxylic acid derivative of formula I [R2 and R3 are each H or a 1-3C alkyl; and Q is a (substituted) phenyl] (e.g. a compound of formula II) in the presence of a nitrogen-contg. aromatic compound (e.g. 5-ethyl-2-methylpyridine) and a boron compound e.g. a borane compound of formula III [R4 to R6 are each hydroxyl, a 1-6C alkoxy, 1-6C alkyl, (substituted) phenyl or the like]}. The above reaction is carried out normally in a solvent, normally at 50-250 deg.C, pref. at 100-200 deg.C for an instant to about 48 h, pref. for 1 to about 24 h.
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