Novel Reaction of NN-Bisarylmethanediamines with Formaldehyde. Synthesis of Some New 135-Triaryl-135-hexahydrotriazines

摘要

The acid-catalyzed cyclocondensation of N,N'-bisaryl (aryl = 2-pyrimidinyl, 2-pyrazinyl and 4-nitrophenyl) methanediamines >5a-c with aqueous formaldehyde in refluxing acetonitrile leads to the formation of the corresponding 1,3,5-triaryl-1,3,5-hexa-hydrotriazines >6a-c. The stoichiometric reactions of 2-aminopyrimidine and 2-amino-pyrazine with aqueous formaldehyde in acetonitrile under reflux conditions also afforded >6a and >6b, respectively. Treatment of 2-aminopyrimidine with aqueous formaldehyde in a 3:2 ratio yielded N,N',N"-tris(2-pyrimidinyl)dimethylenetriamine (>7a) as a sole product, which upon subsequent reaction with formaldehyde also afforded >6a. The reaction of N,N'-biphenylmethanediamine with formaldehyde was also investigated.