One-Pot, Multicomponent Route to Pyrazoloquinolizinones

Abstract

[reaction: see text] An efficient synthesis of 5a-hydroxy-4,5,5a,6,7,8-hexahydropyrazolo[4,3-c]quinolizin-9-ones based on the three-component condensation of 5-aminopyrazoles, aromatic aldehydes, and cyclic 1,3-diketones is described. The multicomponent reaction is performed under strongly basic conditions applying controlled microwave heating in a sealed vessel and involves an unusual base-mediated ring-opening/recyclization of the cyclic 1,3-diketone moiety.