Chemistry of cyanoacetylenes. Part X. Further studies on the reactions of cyano-ynamines with hydrogen halides and bromine

Abstract

4-Chloro-2,4-bis(diethylamino)- and -2,4-bis(dimethylamino)cyclobutene-1,3-dicarbonitrile [(I) and (II)], obtained from the corresponding 3-dialkylaminopropiononitriles and hydrogen chloride, suffered displacement of the chloro-substituent to give the triamines (III) and (IV) on treatment with morpholine and dimethylamine, respectively. Hydrolysis of the products gave the corresponding 2,4-bis(dialkylamino)-4-hydroxycyclobutene-1,3-dicarbonitriles (V) and (VI).

Treatment of the 3-dialkylaminopropiononitriles with hydrogen bromide gave stereoisomeric mixtures of the 4-bromocyclobutenes corresponding to compounds (I) and (II), along with the corresponding NN-dialkyl-4-bromo-6-dialkylaminopyrimidine-2-acetamides. Similar treatment with dry bromine, however, afforded a complex mixture of cyclobutenes; the product distribution varied according to the molecular proportion of bromine used.