Stereochemistry of some bicyclic compounds

Abstract

This thesis is presented in four parts. Part I describes the synthesis of the hydrocarbon 3:4-5:6-dibenzocyclohepta-3:5-diene and the introduction of a carboxylic acid group into the diphenyl nucleus. Onexamination, no evidence of the existence of optical isomerism of the acid could be found. The ultraviolet absorption spectrum of the hydrocarbon, in ethanol solution, showed an inflection at 280 mu, which had hitherto not been recorded. The synthesis of 2:2'-bisbromoethyldiphenyl is described. Condensations of this compound with piperidine gave an unbridged product instead of the expected diphenyl, bridged across the 2:2'-positions with a chain of five atoms to form altogether a nine-membered bridging ring. Treatment of 2:2'-bisbromoethyldiphenyl with diethyl malonate in the presence of sodium ethoxide resulted in loss of the elements of hydrogen bromide and formation of 2:2'-divinyldiphenyl.2-Carbomethoxy-2'-carbomethoxymethyldiphenyl was synthesized and treated with finely divided sodium in xylene. Instead of the expected acyloin-type condensation, a condensation of the Dieckmann type took place, resulting in a diphenyl containing a six-membered bridging ring. Part II is devoted to the synthesis and reactions of 4:5-4':5'-tetramethyldiphenyl. This compound was prepared with the intention of introducing two chloromethyl groups in the 2:2'-positions, and forming a bridging ring by suitable condensations. Only one chloromethyl group could be introduced in the diphenyl nucleus. Part III contains an account of the preparation of di-B-naphthol and the attempts to resolve it. Its dimenthoxyacetic ester was prepared but its dihydrogen succinate and dihydrogen phthalate could not be made. Part IV describes the synthesis of N-benzoyl-2'-bromo-4':6'-dimethyldiphenylamine-3-carboxylic acid, although complete and final proof of its preparation was unobtainable. The treatment of 2'-chloro-N-benzoyl-6-methyl-diphenylamine-2-carboxylic acid with lithium aluminium hydride is also described.