A sequential multicomponent reaction (SMCR) strategy: Synthesis of novel pyrazolo-1,4-dioxaspiro[4,5]decane grafted spiro-indenoquinoxaline pyrrolidine heterocycles

Abstract

A facile and expedient one-pot sequential five-component synthesis of highly substituted trispiro-pyrrolidine heterocycles is described. The key step involves [3 + 2]-cycloaddition of azomethine ylide. This multicomponent reaction (MCR) strategy provides a mild reaction condition, high yield of the products, high regioselectivity, and operational simplicity to assemble complex structural entity in a single operation. The structure of product was confirmed by IR, ¹H-NMR, ¹³C-NMR, and high-resolution mass spectroscopic analysis. A theoretical insight is provided through MM2 calculation for the formation of the observed products.

Graphical Abstract

Keywords:

• Azomethine ylide
• pyrazolo-1,4-dioxa-spiro[4,5]decane
• indenoquinoxaline
• multicomponent reaction (MCR)
• spiro-pyrrolidines

Acknowledgments

Funding University Grants Commission (UGC) (No F.4-5/2018 (FRP-Start-up-Grant) (Cycle IV) (BSR) dated June 2019. Author ARS thanks University Grants Commission (UGC) for the start-up grant under UGC-Faculty Recharge Programme and DG thanks Vels University for the support and encouragement..