Triamino-pyrimidine

With 4,5,6-triamino pyrimidines of which one amino group is secondary, it is the latter which cyclizes preferentially (96). 

H]-Biopterin (97), required for metabolism studies, was synthesised by reaction of the phenylhydrazone of 5-deoxy-[5- H]-L-arabinose (see chapter 12) with 2,5,6-triaminopyrimidin-4-one. The same reaction applied to the semicarbazones of pentoses proceeded regiospecifically to yield D-anapterin (98) and L-primapterin (99), which have the polyhydroxyalkyl substituent in a different position on the pteridinone ring. Condensation of 2-methylthio-4,5,6-triamino-pyrimidine with pentose phenylhydrazones yielded triqrclic adducts such as the crystalline product (100) obtained from D-arabinose . 

Fig. 46. X-Ray structure (left) of the cocrystal of the 1 1 species (right) formed by two complementary components derived from barbituric acid BA (A = ethyl) and 2,4,6-triamino-pyrimidine TAP (B = butyl) [9.119].

The hydrolysis of an 8-azapuiinone usually was more difficult. Thus, 8-azapurin-6-one (31) required heating (with 2 IVhydrochloric acid, 90 C, 2 h) for hydrolysis to 4-amino-l,2,3-triazole-5-carboxamide (32). Further stabilization of the pyrimidine ring, as in 2-amino-8-azapurin-6-one, shifted the site of fission to the triazole ring, and consequently more severe conditions were required (6IV HQ, 150 C, 2 h). The product was 2,4,5-triamino-pyrimidin-6-one. ... 

The first synthesis of these compounds by cyclocondensation of monosaccharides with 5,6-diaminopyrimidines was reported by Karrer and his group in 1947 (47HCA1031). Since then, a great deal of research work has been done on the synthesis of various members of pteridine acyclo C-nucleosides by this method or modifications therefrom. When ketose (652) or aldose (653) monosaccharides were cyclocondensed with 2,5,6-triamino-pyrimidin-... 

S-Nitn>.2.4.6-triamino-pyrimidin 24, 474, 4-Ifydrazoiio-pyrazolon-(5)-oarboii84nTe-(3). hydrazid 25, 249. 

Less common methods to prepare 6-fluoropurines include a thermally assisted ring closure of a triamino pyrimidine (containing a fluoro group) with formamide [113] (Scheme 23) and SnAt reaction of a 6-nitropurine [114] (Scheme 24). 

Cyclization of arylethyl methylsulphinylmethyl ketones in the presence of TFA gives a l-methylthiotetralin-2-one through Pummerer rearrangement of the initially formed trifluoroacetoxysulphonium salt a second example of the use of /3-keto-sulphoxides in synthesis of cyclic compounds concerns condensation with 2,4,5-triamino-pyrimidines to give 6-substituted pteridines. ... 

Pyrimidin-4-one, 2,5,6-triamino- N NMR, 3, 64 (78HCA2108) Pyrimido[4,5-d]pyridazin-5-amine, JV-benzyl-8-chloro-2-phenyl-pXa, UV, 3, 337 <76BSF(2)1549) Pyrimido[4,5-d]pyridazin-5-amine, JV-butyl-8-chloro-2-phenyl-... 

Pyrimido[4,5-d]pyrimidine, 2,4,7-triamino-5-phenyl-diuretic activity, 3, 368... 

However, perhaps the simplest route to quinazoline derivatives involves the heating of 2-aminobenzamides with formic acid to give 4(3//)-quinazolinones, where the formic acid provides the solvent, the C-2 synthon, and the acid catalysis of the ring-closure step. For example, in the synthesis of the imidazoquinazolinone 798, both the imidazo and pyrimidine rings were formed simply by heating the triamino amide 797 in formic acid for 2h <1996JME918>. 

Col microscopic ndls, decomp above 300° without melting. Can be prepd by treating an alkaline aq soln of 2,4,5 triamino-6-hydroxy-pyrimidine with NaNOa + AcOH(Ref 2). Prepn of its hydrochloride is described in Ref 3, which also gives the UV absorption spectra Refs l)Beil — not found 2)R.O.RobIin et... 

Recently it was discovered that cofactor activity with phenylalanine hydroxylase is not limited to tetrahydropterin derivatives. Thus, the substituted pyrimidines 2,4,5-triamino-6-hydroxypyrimidine (21) and 5-(benzylamino)-2,4-diamino-6-hydroxypyrimidine (22) are active in the L-phenylalanine hydroxylating system (78BBR(85)1614, 79JBC(254)5150, 80JBC(255)7774). The amine substituent at C-5 of (21) and (22) is apparently required for... 

Dialkyl- and 2,5,7-trialkyl-pyrimido[4,5-d]pyrimidin-4(3H)-ones have been found to possess pre- and post-emergence herbicidal activity (74USP3830812). 2,4,7-Triamino-5-phenylpyrimido[4,5-if]pyrimidine has diuretic activity similar to triamterene (6-phenyl-2,4,7-pteridinetriamine) (68JMC573). 

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