1-Chloro-1,3-bis(dimethylamino)-2-azapropenylium salts: intermediates for the synthesis of 1,3,5-triazines, pyrimidines, isoquinolines, quinazolines, and a 1,3,5-thiadiazinium salt

Abstract

The title salts, which are formed by the action of dimethylcyanamide on the phosphorus oxychloride complexes of a variety of tertiary amides, are useful precursors of six-membered heteroaromatic compounds: they react with simple amidines to yield 1,3,5-triazines and with N,N-dimethylamidines to give pyrimidines; 3-arylmethyl-1-chloro-1,3-bis(dimethylamino)-2-azapropenylium perchlorates form isoquinolines, the related 3-arylamino-1-chloro-1-dimethylamino-2-azapropenylium salts cyclise to quinazolinium salts, and treatment of 1-chloro-1,3-bis(dimethylamino)-3-phenyl-2-azapropenylium perchlorate with potassium thiocyanate results in a rearranged 1,3,5-thiadiazinium salt.