1,3,5-Triazines. Part XI. Reaction mechanisms and solvent effects in the reactions of cyanuric chloride with NN-diethylaniline and NN-diethyl-1-naphthylamine

The effect of a variety of aprotic solvents on the extent of the reaction and the composition of the products in the reactions between cyanuric chloride and NN-diethylaniline or NN-diethyl-1-naphthylamine has been investigated. Increasing polarity of the solvent increases the reaction rate and favours 'nitrogen-' at the expense of 'carbon-substitution'. Under all conditions investigated the ratio of 'carbon-' to 'nitrogen-substitution' is greater for the naphthylamine than the aniline. The formation of a coloured 1 : 1 charge-transfer complex between the tertiary arylamine and cyanuric chloride is shown to be a necessary, but not sufficient, condition for 'carbon-substitution'. The stability constants for the complexes with the above two amines as well as for the three NN-diethyltoluidines have been evaluated. The reaction mechanisms for 'carbon-' and 'nitrogen-substitution' are discussed.