| 摘要 |
PURPOSE:To industrially and advantageously obtain a precursor for N- alkylquinolonecarboxylic acids useful as agricultural germicides, etc., by thermally rearranging a specific 4-alkoxyquinolinecarboxylic acid ester in the presence of an acid. CONSTITUTION:A 4-alkoxyquinolinecarboxylic acid ester expressed by formula I [R<1> and R<2> are lower alkyl; R<3> is H or lower alkyl; A is H, halogen, lower alkyl, trifluoromethyl, trifluoromethoxy, -OCH2O- (at the 6,7-positions) or formula II (at the 5,6-positions; R<4> is lower alkyl)] is thermally rearranged in the presence of an acid (e.g. concentrated sulfuric acid, etc.) in a molar amount of preferably 0.02-0.1 based on the ester expressed by formula I to afford the aimed compound expressed by formula III.
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