SYNTHESIS AND MOLECULAR STRUCTURE OF 2,3,4,5-TETRAHYDRO-1 H -3-BENZAZEPINE DERIVATIVES AND DIMETHYL 4-CYANO-2,3,6,7-TETRAHYDRO-1 H -3-BENZAZONINE-5,6-DICARBOXYLATE

A study was carried out on the direction of 1,2,3,4-tetrahydroisoquinolinium quaternary salt rearrangements by the action of base with or without dimethyl acetylenedicarboxylate. These quaternary salts containing a methylene group at the nitrogen atom, are converted in the presence of base through intermediate N -ylides into the Stevens rearrangement products, namely, tetrahydro-3-benzazepines. Upon the addition of dimethyl acetylenedicarboxylate as an electrophilic trap, this diester adds at the carbanion site of the ylide with subsequent recyclization of the piperidine fragment to give a 2-benzazonine derivative with an unusual 4,5-positioning of the olefin bond in the nine-membered heterocycle. An X-ray structural analysis established the molecular structures of 2-cyano-3-methyl-2,3,4,5-tetrahydro-1 H -3-benzazepine and dimethyl 4-cyano-2,3,6,7-tetrahydro-1 H -3-benzazonine-5,6-dicarboxylate. Authors: A. T. Soldatenkov, S. A. Soldatova, J. A. Mamyrbekova-Bekro, G. S. Gimranova, A. V. Malkova, K. B. Polyanskii, N. M. Kolyadina, and V. N. Khrustalev English Translation in Chemistry of Heterocyclic Compounds, 2012, 48 (9), pp 1332-1339 http://link.springer.com/article/10.1007/s10593-012-1141-9