Conversion of 2-ethyl- 3, 3, 5, 5-tetramethyl- and 2-ethyl- 1, 3, 3, 5, 5-pentamethyl-1, 2, 4, 5-tetra- hydro-3H-benz-2-azepines by the action of ethyl propiolate

It has been shown that, on interacting 2-ethyl-3, 3, 5, 5-tetramethyl- and 2-ethyl-1, 3, 3, 5, 5-pentamethyl-1, 2, 4, 5-tetrahydro-3H-benz-2-azepines with ethyl propiolate in methanol, fission of the azepine ring occurs at the C(1)-N(2) bond involving a molecule of solvent. The indicated azepines do not react with acetylenedicarboxylic acid ester under these conditions. © 2009 Springer Science+Business Media, Inc.