61175-64-2Relevant academic research and scientific papers
A THEORETICAL AND EXPERIMENTAL INVESTIGATION OF Z,E STEREOISOMERISM IN SOME SIMPLE LIGNIN p-QUINONE METHIDES
Konschin, Henrik,Jakobsons, Juris,Shevchenko, Sergey M.
, p. 231 - 244 (1990)
On the basis of 3-21G ab initio, AM1 semiempirical and molecular mechanics calculations, the structures of the E and Z stereoisomers of the simplest lignin model p-quinone methides, 2-methoxy-4-ethylidene-2,5-cyclohexadiene-1-one (1) and 2-methoxy-4-(2-pr
(E),(Z)-ISOMERISM IN p-QUINONE METHIDES
Shevchenko, S. M.,Apushkinskii, A. G.,Gindin, V. A.,Zarubin, M. Ya.
, p. 921 - 925 (2007/10/02)
The stereoisomeric composition of a set of model p-quinone methides of lignin with successively more complicated structures was studied by 1H NMR spectroscopy.The formation of the p-quinone methides both during oxidation of the corresponding alkylphenols and during dehydration of the corresponding phenol-alcohols is thermodynamically controlled.In all the investigated cases the stereoisomeric ratio E:Z = 0.5 +/- 0.1 is determined not by steric but by electronic factors.During the formation of the p-quinone methide structure a different ratio (E:Z = 1.3 +/- 0.1) is observed as a result of pairing of the phenoxyl radicals.This probably results from kinetic control of the reaction.
