Hexamethylenetetramine

Abstract

(A) Miyazaki et al. reported the preparation of 3,4-dihydroisoquinolines in excellent yield (>90%) using HMTA.9 (B) The biologically active pharmacophore quinazoline was synthesized from benzocarbamate by treatment with HMTA. (C) Efficient aromatization of 1,4-dihydropyridines has been achieved using HMTA iodide. (D) Replacement of the chloro substituent with an ammonium group in the α-chloro ketone was achieved by reaction with HMTA. Similarly, Zhang et al. reported the ammoniation of 2-bromo-1-(3,4- dimethoxyphenyl)ethanone using HMTA. (E) HMTA has wide applications in mono- as well as diformylations of aromatic compounds. For example, the formylation of 5-nitro-7-azaindole using Duff reaction (HMTA/acetic acid) is reported. (F) Cekavicus et al. used HMTA in acidic medium for generating heterocyclic spiro systems via an internal Mannich reaction. (G) HMTA has been proven to be an excellent and inexpensive promoter of the Mannich reaction of aryl alkyl ketones, which was followed by a Nazarov cyclization, providing the 2-alkyl indanones in excellent yields. (H) 3,3′-Diindolylmethane derivatives have been prepared in one pot from indoles and HMTA. HMTA acts as a methylene group donor. © Georg Thieme Verlag Stuttgart. New York.