Synthesis and properties of meta-terphenyl derivatives

Abstract

The study of Hart reaction for the syntheses of m-terphenyl derivatives were performed in a one-pot fashion using excess phenyl Grignard reagent reacting either with 3,5-dibromo-4-iodotoluene or 1,3-dichlorobenzene. Working up the reaction mixtures by various electrophiles gave the corresponding m-terphenyl derivatives. The products were analyzed by proton ([superscript 1]H) and carbon ([superscript 13]C) nuclear magnetic resonance spectroscopy, gas chromatography and mass spectrometry. The m-terphenyl derivatives obtained were 59% of 3,5-diphenyltoluene, 73% of 3,5-diphenyl-4-iodotoluene starting from 3,5-dibromo-4-iodotoluene. When 1,3-dichlorobenzene was used as the substrate, 30% yield of m-terphenyl and 23% yield of 2,6-diphenyliodobenzene were obtained. Three factors affecting the yield of m-terphenyl prepared from 1,3-dichlorobenzene, monitored by Gas Chromatography (GC), were investigated. The most efficient condition was found with the addition of the 1,3-dichlorobenzene substrate into Grignard reagent at low temperature (-10 ํC), using high concentration of the substrate (0.29 M) and runing the reaction at reflux for 3 h