Photocyclization of N-(dialkylaminoalkyl) aromatic 1,2-dicarboximides. X-Ray molecular structure of a stereoisomer of 4-benryl-2-hydroxy-3-phenyl-4,6-diazatricyclo[6.4.0.0]dodeca-1(12),8,10-trien-7-one

Abstract

U.v. irradiation of Mannich bases derived from chloro- or methoxycarbonyl (but not nitro)- substituted phthalimides, pyridinedicarboximides, or naphthalene-2,3-dicarboximide gives rise to products with a new imidazolidine ring. Substrates from unsymmetrical imides lead preferentially (though not exclusively) to one orientation of reaction. Two diastereoisomeric products are often formed, and the relative stereochemistry can be assigned on the basis of n.m.r. data; in one case the stereochemistry is confirmed by X-ray crystallographic analysis. The two diastereoisomers are, under certain conditions, interconverted photochemically.