In an investigation of the Mannich reaction of a variety of phenols, the formation of coloured by-products was observed and was traced to the reaction of certain 1,3-dihydric phenols with organic bases.1 Coloured compounds were found to result from the reaction of 1,3-dihydroxybenzenes (resorcinols) having alkyl and alkenyl substituents, notably cardanol,2 with primary, secondary, primary/secondary (diethylenetriamine) and even tertiary amines. The ...
