Photoinduced Intramolecular Cyclization of 9-(ω-Anilinoalkyl)phenanthrenes

Abstract

Abstract Photoreactions of a series of compounds of the type 9-phenanthryl–A–CH2NHC6H5[–A–=o-phenylene (1b), –(CH2)2– (1c), –(CH2)3– (1d), –(CH2)4– (1e), –CH2– (1f)] in benzene were studied. From 1b–d, the spiro compounds are obtained by an intramolecular cis-addition of the N–H function to the C9, C10-double bond of the phenanthrene ring. These photoproducts can be converted to the starting materials by treating with trifluoroacetic acid or heating above their melting temperatures. The mechanistic features of these reactions are described.