4-Hydroxy-2,4,5-triaminopyrimidine

The title compound is one of several possible tautomers. As established by X-ray crystallography, the doubly protonated derivative 2,4,5-triamino-1,6-dihydropyrimidin-6-one, which is red-orange, can be obtained as the sulfate salt. ==Preparation and biosynthetic significance==

In historic work, 4-hydroxy-2,4,5-triaminopyrimidine was shown to condense with formic acid to give guanine, a nucleic acid found in both RNA and DNA (not recognized at the time of its synthesis). Traube et al. had previously made 4-hydroxy-2,4,5-triaminopyrimidine by cyclization of cyanoacetylguanidine. Like most aromatic 1,2-diamines, 4-hydroxy-2,4,5-triaminopyrimidine condenses with glyoxal to give a pterin. The biosynthesis of riboflavin proceeds via this diamine, which is derived from guanine. 4-Hydroxy-2,4,5-triaminopyrimidine can be prepared in the laboratory from simple precursors that may be relevant to the origin of life. Reminiscent of the early work of Traube et al., it arises by condensation of guanidine, aminomalononitrile (trimer of HCN), and aminocyanoacetamide. ==References==