Synthesis of pyrazolopyrano pyrimidines via one-pot solvent free greener approach utilizing lanthanum trifluoroacetate and trichloroacetate Lewis acids supported on mesoporous silica: An experimental and DFT studies

Abstract

Herein, an economic, environment-benign and sustainable greener protocol was developed for the production of pyrazolopyrano pyrimidines utilizing water competent Lanthanum trifluoroacetate and trichloroacetate Lewis acids based over silica via one-pot reaction involving aromatic aldehydes, ethyl acetoacetate, hydrazine hydrate and barbituric acid. The capability to incorporate a broad spectrum of functional groups, fast reaction times, best product yield, gentle reaction medium, solvent-free synthesis and the easy recoverability and multiple-time reusability of catalysts are notable advantages of the present synthetic approach. Furthermore, DFT studies was employed to study the pyrazolopyrano pyrimidines (5a-l), highlighting role of computational methods in predicting and understanding reactivity. Consequently, the integration of DFT studies with synthesis has proven to be a potent strategy for creating the current synthesis method.