A novel pseudo six-component synthesis of functionalized pyrazoles in ethanol by cascade reaction
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Novel-substituted pyrazoles were synthesized using an aminal-based approach. The key steps in the synthetic strategy involve the formation of 1,1-dihydrazino-2-nitroethylene from hydrazine hydrate with nitro ketene dithioacetal and its reaction with Knoevenagel adduct derived from the corresponding aldehyde and malononitrile in ethanol media. The formation of 5-membered pyrazole ring is confirmed based on the electrostatic surface potential computed by density functional theory. This strategy can provide a concise and eco-friendly route for easy access to the highly substituted pyrazoles derivatives in excellent yields using four simple and readily available building blocks under mild conditions and particularly attractive due to features such as atom economy, high yield and mild condition.
KeywordsPseudo six component Functionalized pyrazoles Nitro ketene dithioacetal Geometric isomer
Financial support of this research from Alzahra University, Iran, is gratefully acknowledged. A. Rezvanian is also thankful to Iran National Science Foundation (INSF) for the allocated grant by the awarded individual research chair.
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