Stereochemistry of diphenyls

Abstract

This thesis is divided into two sections. Part 1 describes the synthesis of various alkyldiphenyls. The ultraviolet absorption spectra of these diphenyls were examined in order to study the relation between configuration and conjugation. The diphenyls prepared include 2-ethyl-,2:2'-diethyl-, 3:3'-diethyl- and 4:4'-diethyldiphenyl; 2-iso-propyl-, 2:2'-di-isopropyl-, 4:4'-di-isopropyl,/2:2':4:4'-tetra-isopropyldiphenyl. 6:6'-Di-isopropyldiphenyl-3:3'-di-carboxylic acid and 2'-isopropyldiphenyl-2-carboxylic acid were obtained as intermediaries and the optical properties of these two acids were studied in an attempt to correlate the evidence of steric hindrance as shown through optical activity with the evidence shown by the ultraviolet absorption spectra. 2'-( ?-Hydroxyisopropyl)-diphenyl-2-carboxylic acid was initially used as starting material in the synthesis of the latter compound and the mode of its dehydration under different conditions studied. Under acid conditions 9:9-dimethylfluorene-4-carboxylic acid was obtained and from this 9:9-dimethyl-fluorene, 4-isopropenyl-, and 4-isopropvl-9:9-dimethvlfluorenewere prepared and the ultraviolet absorption spectra determined. Part II describes the preparation of 2:2'-dimethyl-6-aminodiphenyl. The first method tried led to 2:2'-dimethyl-5-aminodiphenyl. 2:2' :4:4'-Tetramethyl-6-aminodiphenyl was also prepared and converted into 2:4:5:7-tetramethyl-9-(p-nitrophenyl)-phenanthridine, spectroscopic evidence being used to confirm its structure. Finally the phenanthridine was reduced to 2:4:5:7-tetramethyl-9-(p-aminophenyl)-phenanthridine. It has not yet been possible to obtain this compound in an optically active condition.