Highly regioselective and practical synthesis of 1-acyl-5-hydroxypyrazolines and 1-acyl pyrazoles from 1,2-allenic ketones and hydrazides
作者:Shenghai Guo、Jiliang Wang、Dongqiang Guo、Xinying Zhang、Xuesen Fan
DOI:10.1016/j.tet.2012.07.046
日期:2012.9
A mild and highlyregioselectivesynthesis of 1-acyl-5-hydroxypyrazolines has been achieved through the condensation of 1,2-allenic ketones with hydrazides in the absence of any catalyst. Moreover, the obtained 1-acyl-5-hydroxypyrazolines can be easily transformed into 1-acyl pyrazoles under the promotion of BF3·Et2O. It was also found that 1-acyl pyrazoles can be produced directly from allenic ketones