The Formation of Squaramic Acids and Squaryl Diamides by the Reaction of Squaric Acid with Alkyl Isocyanides

Abstract

The reaction between squaric acid with one equivalent of alkyl isocyanides such as t-butyl isocyanide, cyclohexyl isocyanide and n-butyl isocyanide in ethanol at room temperature after 3h afforded the corresponding squaramic acid derivatives. Symmetric 2,4-squaryl diamides were obtained when the reaction of squaric acid was carried out with two equivalents of alkyl isocyanides under the same conditions. Asymmetric 2,4-squaryl diamides were obtained by reaction of squaramic acids with one equivalent of alkyl isocyanides.