Anhydride formation with thionyl chloride. The synthesis of di- and tri-amino-alcohols from the corresponding tri- and tetra-carboxylic acids

Abstract

The preparation of NN-dialkyl-substituted amides of pentane-1,3,5-tricarboxylic acid did not proceed normally owing to formation of anhydride during conversion of the acid to acid chloride with thionyl chloride. Since anhydride formation appeared to involve the central carboxyl groups of two molecules, reduction of the resulting amides gave, in addition to the expected triamines, diamino-alcohols where the hydroxyl group was central and the amino-groups were terminal. Similar reactions occurred when heptane-1,3,5,7-tetracarboxylic acid was treated with thionyl chloride.