作者:Barrington Cross、Robert L. Arotin、Charles F. Ruopp
DOI:10.1002/jhet.5570170512
日期:1980.7
A rapid, convenient conversion of 1,2-dimethylpyrazolium salts (1) to 1-methylpyrazoles (2) is accomplished in piperidine or 3-methylpiperidine at temperatures ≥ 106°. This demethylation represents a particularly useful procedure for the synthesis of 3- and 5-substituted aminopyrazoles, which are not readily obtainable by other methods. The 50:50 mixture of piperidinopyrazole isomers 2b can be obtained
在哌啶或3-甲基哌啶中于≥106°C的温度下,可以快速,方便地将1,2-二甲基吡唑鎓盐(1)转化为1-甲基吡唑(2)。该脱甲基代表了合成3-和5-取代的氨基吡唑的特别有用的方法,其不易通过其他方法获得。哌啶子基吡唑异构体2b的50:50混合物可通过在乙醇中以哌啶在106°下处理3-氯-1,2-二甲基-二甲基-5-苯基吡唑碘化物(3b)来直接获得。