Selective synthesis of functionalized pyrazoles from 5-amino-1H-pyrazole-4-carbaldehydes with sodium nitrite: 5-Amino-4-nitrosopyrazoles and pyrazole-4-carbaldehydes
作者:Rong-Hong Hsiao、Ching-Chun Tseng、Jia-Jun Xie、Shuo-En Tsai、Naoto Uramaru、Ching-Ya Lin、Ching-Yuh Chern、Fung Fuh Wong
DOI:10.1016/j.tet.2019.06.048
日期:2019.8
and efficient redox reaction was developed to react 5-amino-1H-pyrazole-4-carbaldehyde with sodium nitrite (NaNO2) in an acidicsolution (HCl/MeOH) to generate 5-amino-4-nitrosopyrazole, pyrazole-4-carbaldehyde, or diazenylpyrazole selectively. The results showed that 5-amino-4-nitrosopyrazoles were formed as the major product in the dilutedacidicsolution (≤2 N HCl in MeOH solution) through redox, formylation
开发了一种新颖有效的氧化还原反应,使5-氨基-1 H-吡唑-4-甲醛与亚硝酸钠(NaNO 2)在酸性溶液(HCl / MeOH)中反应生成5-氨基-4-亚硝基吡唑,吡唑- 4-甲醛或二重氮基吡唑选择性地。结果表明,通过NaNO 2的氧化还原,甲酰化和亚硝化反应,在稀释的酸性溶液(≤MeOH中的2 N HCl)中形成了以5-氨基-4-亚硝基吡唑为主要产物。有趣的是,在6 N HCl的MeOH溶液中,吡唑-4-甲醛是主要产物。