VARIOUS APPROACHES TO 4-(PYRROLIDIN-2-YL)PYRAZOLES

Аннотация

A reliable systematic approach to a series of substituted 4-(pyrrolidin-2-ylidene)pyrazol-5-ones was developed. The compounds were synthesized through the reaction of pyrazol-5-ones with cyclic lactim ethers or lactam acetals. Subsequent treatment with phosphorus oxychloride yielded 5-chloro-4-(3,4-dihydro-2H-pyrrol-5-yl)-1H-pyrazoles, which possess both an active chlorine atom and an imine group. These intermediates underwent stepwise reduction – either targeting the imine group followed by reductive dechlorination, or vice versa – a direct reduction to produce 4-pyrrolidin-2-yl)pyrazoles. These products serve as valuable building blocks in medicinal chemistry, offering potential for further functionalization and application in drug design.