Kondensationsreaktionen von Lignin-Modellsubstanzen mit Phenol unter saurer Katalyse - 2. Mitteilung

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Abstract
Substituted 1-guaiacyl- and 1-veratrylpropanes were reacted with phenol, and HCl as catalyst, under mild conditions (80.degree. C, 2 h, atm. pressure). Condensation reactions led to the formation of a C.sbd.C-bond between the benzylic carbon of the model compound and the phenol, yielding 1,1-diarylpropane structures. Formation of C.sbd.C-bonds between the C-2 of the side chain of the model compound and the phenol occurs only in the case of the presence of a benzylic hydroxyl group in a neighboring group reaction (phenonium rearrangement). The formation of guaiacol by the cleavage of the .beta.-aryl ether bond and exchange of the aromatic nucleus seen in the model experiments could be observed on various samples of wood and lignin.