Reactions of benzotriazole with formaldehyde and aliphatic primary amines: selective formation of 1 : 1 : 1, of 2 : 2 : 1, and of 2 : 3 : 2 adducts and a study of their reactions with nucleophiles

Abstract

Benzotriazole (BtH) reacts easily with aliphatic primary amines and formaldehyde in aqueous media to give one or more of three types of product: (i)(BtCH₂)₂NR (5), (ii)(BtCH₂NR)₂CH₂(6), and/or (iii) BtCH₂NHR (7). The product formed depends on the molar ratio of the substrates, and on the degree of steric hindrance in the amine, and is also influenced by the nature of the solvent. Primary aliphatic 1,2- or 1,3-diamines yield cyclic aminals which are imidazolidine (8a) and hexahydropyrimidine (8b) derivatives. Reactions of these aminals with Grignard reagents, and with cyanide anion as nucleophiles, are also described.