One-Pot Synthesis of Coumarins Unsubstituted on the Pyranic Nucleus Catalysed by a Wells–Dawson Heteropolyacid (H₆P₂W₁₈O₆₂)

Abstract

The development of a method to produce coumarins unsubstituted on the pyranic nucleus catalyzed from Wells–Dawson heteropolyacid (H6P2W18O62), phenol derivatives and ethyl 3,3-diethoxypropionate using Pechmann condensation under solvent-free conditions is described. This catalytic method was also applied successfully to synthesize various substituted coumarins, including the corresponding phenols and ethyl 3,3-diethoxypropionate. This work provides a novel, cheaper and safer way to syhthesize coumarins unsubstituted on the pyranic nucleus.

A review on convenient synthesis of substituted coumarins using reuseable solid acid catalysts

“…This work provides a novel, cheaper and safer way to synthesize coumarins unsubstituted on the pyranic nucleus ( Scheme 20 ). 77 Initially, they optimized the reaction conditions by exploring a model reaction between 2-methyl-3-hydroxy-phenol and ethyl 3, 3-diethoxypropionate. The effect of the temperature and reaction time were investigated and results were summarized in Table 24 .…”

Recent Advances in the Synthesis of Coumarin Derivatives from Different Starting Materials

“…All reaction steps are shown in Scheme 53 on a resorcinol example. Sun et al have developed a method for the of coumarins unsubstituted on the pyranic nucleus, under solvent-free conditions (Scheme 54) [110]. First, model reaction of 2-methyl-3-hydroxyphenol and ethyl 3,3-diethoxypropionate were performed in order to choose efficient catalyst and to optimize reaction conditions.…”