Meldrum's Acid in Organic Synthesis, an Outlook to Reaction Media

Meldrum's acid, a white solid which was prepared for the first time by Andrew Norman in 1908, is a versatile and efficient motif in chemistry. The rigid structure, low steric hindrance, in addition with high acidity of the C5–H, are some unique chemical properties of this O-containing heterocycle. Several organic compounds based on Meldrum's acid have interesting applications in biology, industry and drugs. Its special structure makes it a good target for both nucleophilic as well as electrophilic attack. Preparation of different forms of these scaffolds, with a glance on the reaction media, has been reviewed. In addition, other part of the manuscript is based on heat and solvent of the reaction media. These factors focused on green chemistry rules. This review classified the multi-component transformations of Meldrum's acid as one of their substrates with respect to these two important aspects of green synthesis up to middle of 2016.