β-aminoenones in the regioselective synthesis of 1,3,5-trialkylpyrazoles.: The influence of the substituents in the mechanism and the regioselectivity of the reaction

被引:11
作者
Alberola, A [1 ]
González-Ortega, A [1 ]
Sádaba, ML [1 ]
Sañudo, MC [1 ]
机构
[1] Univ Valladolid, Fac Ciencias, Dept Quim Organ, E-47005 Valladolid, Spain
来源
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 1 | 1998年 / 24期
关键词
D O I
10.1039/a807692h
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
beta-Aminoenones react with monoalkyl hydrazines to give regioselectively 1,3,5-trisubstituted pyrazoles. The mechanism and level of regioselectivity depend on both the substitution pattern of the substrates and the reaction conditions. When the least bulky substituent is attached at the beta-position of the enone, a high regioselectivity is obtained, usually higher than that from equivalent beta-diketones. If the beta-substituent is the bulkiest group, the regioselectivity decreases. Nevertheless, in the conditions reported in this paper, it is possible to prepare pyrazoles not obtainable from beta-diketones.
引用
收藏
页码:4061 / 4065
页数:5
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