Stufenweise Synthese von Homologen des Äthylbenzols («gesättigte Oligostyrole»)

Abstract

A general method for the synthesis of homologous ethyl benzene derivatives (saturated oligostyrenes) was developed, leading to a head-tail combination. The condensation of β-bromoethyl benzene with benzyl cyanide gives in liquid ammonia with sodium amide the next higher homologous nitril. The carbonic acids were obtained by saponification and the alcohols by reduction. The tosyl derivatives result from the esterification of the alcohols with p-toluenesulfonic chloride. They could be converted either by reduction with lithium aluminium hydride to the hydrocarbons or by reaction with lithium bromide in acetone to the β-bromoethyl benzenes. These bromides can react again with benzyl cyanide in the same manner to the next higher nitrile derivative, and so on.
In this way gaschromatographically pure 1,3-diphenylbutane, 1,3,5-triphenylhexane and 1,3,5,7-tetraphenyloctane were prepared. The next higher oligomers up to the heptanederivative could be synthesized, but they could not yet be prepared in pure state.
The four isomeric forms of the triphenylhexane could all be isolated. All intermediates (bromides, nitriles, carbonic acids, alcohols and tosyl-derivatives), as well as the hydrocarbons were synthesized in very good yield. Physical data characterizing the pure preparations are compiled.