Treatment of 4-chloro-2-dimethylaminopyrimidine (1a) and its 5-phenyl derivative (1b) with potassium amide in liquid ammonia and subsequent workup of the reaction mixtures lead to the formation of 2-dimethylamino-4-methyl-s-triazine and 4-benzyl-2-dimethylamino-s-triazine, respectively. By extensive 13C NMR investigations of both reaction mixtures in liquid ammonia containing potassium amide, a number of unstable intermediates could be identified: from 1a the 1:1 anionic σ complex 2a and the anionic open-chain intermediate aminoethynyldiazabutadiene 3; from 1b, the σ complex 2b and the anionic aminodiazabutadiene 7, but also a redox product of 7, i.e., the cyanoaminoazabutadiene 8. Based upon the results of a deuterium labeling experiment it is assumed that the conversion of 7 into 8 occurs by an intramolecular oxidation-reduction process.
|Journal||Journal of Organic Chemistry|
|Publication status||Published - 1978|