A novel and sustainable method for synthesizing pyranopyrazole derivatives is introduced, utilizing theophylline as a catalyst in a solvent-free process at ambient temperature. This one-pot multicomponent reaction (MCR) effectively combines aromatic or heteroaromatic aldehydes, ethyl acetoacetate, malononitrile, and hydrazine hydrate to produce the desired compounds in high yields. Key advantages of this protocol include its eco-friendly nature, clean reaction profile, minimal reaction time, and simplified workup procedure. The approach also demonstrates excellent atom economy, contributing to reduced waste generation and enhanced process sustainability.
Thorat et al. (Mon,) studied this question.