Regiocontrolled Synthesis of 1-Substituted-3(5)-carboxyalkyl-1H-pyrazoles Using Trichloromethyl Enones.

ABSTRACT: In this work, we present a regiocontrolled methodology to prepare 1-substituted-3(5)-carboxyalkyl-1H-pyrazoles using trichloromethyl enones as starting materials. It was found that the selectivity of the reaction depends on the nature of the hydrazine: when using arylhydrazine hydrochlorides, synthesis of the 1,3-regioisomer was achieved (22 examples, 37-97% yields), while the corresponding free hydrazine led exclusively to the 1,5-regioisomer (12 examples, 52-83% yields). The trichloromethyl group was used as a precursor for the carboxyalkyl moiety, furnishing a one-pot three-component regioselective protocol suitable for preparing both isomers at moderate to excellent yields. The selectivity of the reaction was investigated through NMR analyses and the structures of the products w

SUBMITTER: Pereira GS 

PROVIDER: S-EPMC10193424 | biostudies-literature | 2023 May

REPOSITORIES: biostudies-literature