【摘要】 本文研究了2,6-二烷氧基苯乙酮腙在多聚磷酸(PPA)存在下受热脱去一分子醇环化生成3-甲基-4-烷氧基吲唑的合成反应.并研究了水杨醛、邻甲氧基苯甲醛、2,4-二羟基苯甲醛以及邻羟基苯乙酮、2-羟基-3,5-二甲基苯乙酮腙在PPA存在下的受热反应过程.更多还原

【Abstract】 In this paper, we put forward a new and convenient method for the synthesis of 1H-indazoles. In the presence of PPA, the cyclization of a series of 2,6-dialkoxyl (or hydroxy)ace-tophenone hydrazones(2a-f) gave 3-methyl-4-alkoxyl ((?) hydroxy)-1H-indazoles (3a-f). This new method offers several advantages: easy access of the reagents, reasonable yield and short reaction time. We also studied its applied range. The application of this method to 2-methoxy-4,6-dimethylacetophenone hydrazone (2g) gave 3, 4,6-trimethyl-1H-indazole (3g). But the application of it to salicyaldehyde, o-methoxybenzaldehyde, 2,4-dihydroxybenzaldehyde or o-hydroxy-acetophenone, 2-hydroxy-3, 5-dimethylacetophenone hydrazones (2h-l) could not bring about ring closure, resulted in the formation of the corresponding azines (3h-l) in excellent yields.更多还原