2-hydroxy-6-amino-pyrimidine

Cytosine (2-hydroxy-6-amino-pyrimidine), uracil (2,6-dihydroxypyrimidine), and thymine (5-methyluracil) are pyrimidine derivatives adenine (6-aminopurine), guanine (2-amino-6-hy-droxypurine), and xanthine (2,6-dihydroxypurine) are purine derivatives (Fig. 5). 

Cytosine(2-Hydroxy-6-amino-pyrimidine) Uracil (2,6-Dihydroxy-pyrimidme) Thymine (2,6-Dihydroxy-6-methyl-pyrimidine)... 

A similar effect occurs in the reaction of some pyrimidine nucleoside derivatives with hydroxylamine. Studies of the mechanism of this reaction with uridine derivatives340 shows that the initial point for nucleophilic attack is at C-6, and the resultant 5,6-dihydro-6-(hydroxy-amino)uridine derivative (86) is an intermediate in the conversion of the uridine derivative into the ribosylurea derivative 87 and 2-isoxazolin-5-one (88), as shown in Scheme 8. 

L-Amino-2-hydroxy-5-(hydroxy-methy1)pyrimidine, AE38 U-Amino-2-hydroxy-5-methyl -pyrimidine, AE36 1-Am i no-7-hydroxyna phtha1ene,... 

Pyrido(2,3-d]pyrimidin 4-Hydroxy-amino-2-phenyl- Elba, 20 ( —CN + NH2 —OH/Cycl.) Pyrimido 4,5-d]pyridaziu 8(or5)-Hydroxy-4-methyl-5(or8)-phenyl- E9c, 352 (3-OH-... 

Brom-l-hydroxy-indan wird durch Natrium/fl. Ammoniak in 75°/o-iger Ausbeute zu 2-Hydroxy-indan (F 70°) reduziert8. Bei —40 bis -35° werden 4-mono- und 4,6-dihalo-genierte 2-Amino-pyrimidine durch Natrium/fl. Ammoniak in mittleren Ausbeuten zu 2-Amino-pyrimidinen hydrogenolysiert9 z. B. ... 

Formyl acetic acid and guanidine undergo cyclization after condensation in the presence of fuming sulphuric acid with the loss of two moles of water. The cyclized product imdeigo keto-enol tautomerism, when the enoMorm, i.e., 4-hydroxy-2-amino pyrimidine is subsequently chlorinated with either phosphorus oxychloride (POCI3) or chlorosulfonic acid (CISO2OH) and finally reduced with zinc metal and ammonium hydroxide to obtain 2-amino-pyrimidine. 

Cysteine had also been found to add photochemically to poly U, poly C, and DNA, thus adding credence to Smith and Aplin s postulate that the formation of a heterodimer between a pyrimidine and a sulfur (or hydroxy) amino acid may constitute a mechanism for the photochemical cross-linking of DNA and protein in vivo (Smith, 1962, 1964 Smith et al, 1966). Infrared data suggested that the COOH and amino groups of the cysteine residue were free, implying that the linkage to the uracil skeleton was through the sulfur bond. 

Methyl-4ramino-5-hydroxy-methyl-pyrimidine, VII, 104 2-Methyl-4rBminopyrimidyl-5-methyl-amino dihydrochloride, activation of apocarboxylase by, VII, 90... 

More recently a very large number of substituted pyrimidines have been studied by many workers [16—18, 22, 37,38], and it is now well established that hydroxy derivatives do not exist as such, but in the non-aromatic form. However amino pyrimidines and other derivatives are fully aromatic and their spectra are closely related to those of benzene and pyridine [42—44, 61, 62]. 

The reaction of 6-amino-5-(l,2-diethoxycarbonylhydrazino)pyrimidines with enamines represents another convenient method for the preparation of pteridines. Fusion of 5-(l,2-diethoxycarbonylhydrazino)-2,4,6-triaminopyrimidine (281) with an excess of mor-pholinocyclohexene leads to 2,4-diaminotetrahydrobenzo[g]pteridine, and with the morpholinoenamine (282) from 17/3-hydroxy-5a-androstan-3-one regioselective condensation to the fused pteridine (283) takes place in almost quantitative yield (equation 101) (71CC83). 6-Amino-5-nitroso- and 6-amino-5-phenylazo-pyrimidines react similarly, imitating the Timmis-type reaction (72CPB1428). 

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