A Brief Review on Different Reactions of Rhodanine

Abstract

2-Thioxo-4-thiazolidinone which is trivially known as rhodanine is a five-membered heterocycle, containing a sulfur and nitrogen atom at 1 and 3 positions, respectively. It is a very attractive class of compounds, because derivatization of rhodanine yields a number of molecules having multifarious application in medicinal chemistry and biology. There are many molecules derived from rhodanine which are already being used commercially as drug molecules. So owing to the importance of rhodanine in the field of medicinal chemistry and biology, a comprehensive review familiarizing different derivatives of the parent molecule rhodanine and their syntheses is highly warranted. In this review, we have broadly categorized the reactions of rhodanine as; (a) Knoevenagel condensation through the C-5 active methylene group with carbonyl compounds, (b) nucleophilic attack on thioxo group at position 2 of rhodanine by aliphatic amines, (c) thioxo to oxo conversion, and (d) all other reactions. So far, to the best of our knowledge, no such literature which accounts for all the different kinds of reactions of rhodanine is reported. Here, we have not only presented the reactions schemes from various literatures, but we have discussed about the advantages and inadequacies of that particular catalytic processes. Moreover, at the end of this article we have given our own critical analysis on these literature reports, based on our understanding and experience.