Über die Struktur der Acrylnitril-Guanidin-Kondensate Über Heterocyclen, 78. Mitt.

Abstract

Repetition of the work ofSugino andTamaka ¹ showed that acrylonitrile and guanidine react inDMF to yield not only 3,4,6,7-tetrahydro-2H-pyrimido[1,2—a]pyrimidine-2,8(1H)-diimine (1), but a mixture (F) of1 (as a main product) and 2-amino-4-imino-1,4,5,6-tetrahydropyrimidine-1-propionitrile (7) besides one or two bases not identified so far.1 and7 were isolated as picrates. For the prove of their structures,1- and7-picrate were also prepared by an unequivocal synthesis starting from iminodipropionitrile hydrochloride8 · HCl: The latter on reaction with cyanamide gave9 which cyclized to afford a mixture of1,7 and 2-amino-4-oxo-1,4,5,6-tetrahydropyrimidine-1-propionitrile (10). The picrates of1 and7 were identical with those prepared from the acrylonitrileguanidine-condensateF. This result supports the prior proposed¹ structures of pyrimidopyrimidine1 and of4,5 and6, obtained by hydrolysis of1. Nmr-, ir-and some of the mass spectra of1,4,7–10 (and their salts) are reported.