Reaction of 2-dimethylaminomethylene-1,3-diones with dinucleophiles. VI. Synthesis of ethyl or methyl 1,5-disubstituted 1<i>H</i>-pyrazole-4-carboxylates
作者:Giulia Menozzi、Luisa Mosti、Pietro Schenone
DOI:10.1002/jhet.5570240634
日期:1987.11
Reaction of ethyl or methyl 3-oxoalkanoates with N,N-dimethylformamide dimethyl acetal gave, generally in excellent yields, a series of ethyl or methyl 2-dimethylaminomethylene-3-oxoalkanoates II which reacted with phenylhydrazine to afford the esters of 5-substituted 1-phenyl-1H-pyrazole-4-carboxylic acids III in high yields. Esters III were hydrolyzed to the relative 5-substituted 1-phenyl-1H-pyrazole-4-carboxylic
3-氧代链烷酸乙酯或甲基酯与N,N-二甲基甲酰胺二甲基乙缩醛的反应通常以优异的产率得到一系列乙基或甲基2-二甲氨基亚甲基-3-氧代链烷酸酯II,其与苯肼反应得到5-取代的1的酯。 -苯基-1 H-吡唑-4-羧酸III高收率。将酯III水解成相对的5-取代的1-苯基-1 H-吡唑-4-羧酸,将其通过加热转化成5-取代的1-苯基-1 H-吡唑以优异的产率转化。的反应II与甲基肼在3-和一般的混合物,得到5-取代的乙基1-甲基-1- ħ-吡唑-4-羧酸酯,除IIg以外,产生高产率的5-苄基-1-甲基-1 H-吡唑-4-羧酸甲酯,将其水解为相对的吡唑羧酸。通过以定量收率加热5-苄基-1-甲基-1 H-吡唑来提供。