According to four different methods, various types of N-acylpyrazoles were prepared from the corresponding pyrazoles and carboxylic acids or their acid chlorides. Although N-acylpyrazoles were inert to alcohols under neutral or weakly basic conditions, the alcoholysis was dramatically accelerated by the action of strong acid or base. On the basis of these chemical properties, the regioselective synthesis of methyl benzyl 2,2-dimethylglutarate was achieved by selective protection and functionalization of a carboxylic acid derivative using N-acylpyrazoles.
根据四种不同的方法,从相应的
吡唑和
羧酸或其酰
氯制备了多种类型的N-酰基
吡唑。尽管在中性或弱碱性条件下,N-酰基
吡唑对醇呈惰性,但强酸或碱的作用下,醇解反应显著加速。基于这些
化学性质,通过选择性保护和功能化
羧酸衍
生物,成功实现了甲基苄基
2,2-二甲基戊二酸酯的区域选择性合成。