Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

Diaminoquinone methides Xa-Xe were prepared by aminolysis of the dicyanoquinone methide IX. From the isolated intermediates XI and XIII a four-step mechanism was deduced, involving addition and elimination steps in the order Ad-E-Ad-E. Condensation of N,N,N',N'-tetramethylchloroformamidinium chloride with 2,6-ditert-butylphenol afforded bis(dimethylamino)-quinone methide Xc which on transamination was converted to the diaminoquinone methides Xa and Xb. Analysis of physico-chemical data of diaminoquinone methides leads to the conclusion that their structure can be represented by the zwitterionic formula XVII rather than the quinonoid formula X.