“On water” synthesis of N-unsubstituted pyrazoles: semicarbazide hydrochloride as an alternative to hydrazine for preparation of pyrazole-3-carboxylate derivatives and 3,5-disubstituted pyrazoles
作者:Violeta Marković、Milan D. Joksović
DOI:10.1039/c4gc02028f
日期:——
A green, simple and highly efficient method for the synthesis of pyrazole-3-carboxylates and 3,5-disubstituted pyrazoles by cyclization of 4-aryl(hetaryl, alkyl)-2,4-diketoesters and 1,3-diketones with semicarbazide hydrochloride under “on water” conditions has been developed. This method also does not require toxic hydrazine and product purification, eliminating the use of toxic liquid chemicals.
一种绿色,简单且高效的方法,通过用氨基脲盐酸盐将4-芳基(杂芳基,烷基)-2,4-二酮酸酯和1,3-二酮环化,合成吡唑-3-羧酸酯和3,5-二取代的吡唑在“水上”条件下已经开发出来。该方法也不需要毒性肼和产物纯化,从而消除了对有毒液体化学物质的使用。