A Facile Synthesis and Characterization of Meulenhoff'S Free Acid Derived from 1, 1′-Biphenyl-2, 2′-Diol and Its Alkaloid Complexes

Abstract

A facile synthesis, separation and characterization of Meulenhoff 's free acid (HBB) derived from 1, 1′-biphenyl-2, 2′-diol were described. HBB, prepared by refluxing a mixture of l, l'-biphenyl-2, 2′-dio] and boric acid in benzene for 3 h, reacted with bulky alkaloids (quinine, quinidine, cinchonine, cinchonidine, brucine and strychnine) in equimolar ratio in benzene or chloroform under reflux to give spiro[6, 6]borate complexes in 72–99 % yields. Their IR and 'H NMR spectral characteristics are presented and discussed.