Hydroxy hypoxanthine

The amino groups are replaced with oxygen. Although here a biochemical reaction, the same can be achieved under acid-catalysed hydrolytic conditions, and resembles the nucleophilic substitution on pyrimidines (see Section 11.6.1). The first-formed hydroxy derivative would then tautomerize to the carbonyl structure. In the case of guanine, the product is xanthine, whereas adenine leads to hypoxanthine. The latter compound is also converted into xanthine by an oxidizing enzyme, xanthine oxidase. This enzyme also oxidizes xanthine at C-8, giving uric acid. 

Since chemistry of pterines and purines has been already reviewed (42,48,491), only recent studies will be described here. Guanine (93) was prepared by reaction of 4-hydroxy-2,5,6-triaminopyrimidine sulfate (588 see Scheme 73) with HCONH2 with removal of H2O from the reaction system in an excellent yield (492). Also, irradiation of oxygenated aqueous solutions of 6-mercaptopurine with near-UV light gave hypoxanthine (92) as a minor product (< 10%) together with purine-6-sulfinate (589). It also arises from degradation of purine-6-sulfonate obtained from photooxidation of the sulfinate (589) (493). 

Our laboratory conducted the most extensive investigation of the 2,4,1-benzodiazaborines reported to date. We focused attention on l-hydroxy-lff-2,4,l-benzoxazaborine (50a), 1,2-dihydro-l-hydroxy-2,4,l-benzodiazaborine (50b), and 3-amino-l,2-dihydro-l-hydroxy-2,4,l-benzodiazaborine (50c) because their peripheries so closely matched the pyrimidine ring ones of the naturally occurring purines adenine, hypoxanthine, and guanine, respectively <94JA7597>. 

Adenine, guanine, guanylurea, and several s-triazines and ureas have been detected in HCl-extracts of Orgueil and Murchison (Hayatsu, 1964 Hayatsu et al, 1968, 1975). The first 3 were confirmed by Stoks and Schwartz (1981), but the s-triazines were not they may have formed from guanylurea in the isolation and identification procedure. Other compounds detected are xanthine, hypoxanthine, and uracil (van der Velden and Schwartz, 1977 Stoks and Schwartz, 1979). A report of 4-hydroxy-pyrimidine and several related compounds (Folsorae et al, 1973) was not confirmed (Hayatsu et al, 1975 van der Velden and Schwartz, 1977) these compounds, which... 

It will be appreciated that it is also possible to write oxo-n//-purines in different ways, i.e. in the lactam (oxo-nH) form as with (13) and in a lactim (hydroxy form) as with the alternate structure for hypoxanthine (14). However there is little doubt (see later) that both in the solid state and in solution, except at high pH, these particular derivatives exist almost exclusively in the oxo-nH forms. 

Purine 9-oxides on the other hand are best made from imidazole precursors. Thus 9-hydroxy-8-methylxanthine (368) and hypoxanthine (369) have been most conveniently obtained by cyclization of 5-amino-l-benzyloxy-2-methylimidazole-4-carboxamide (370) with carbonate or formate esters, respectively, and debenzylation of the intermediate benzyloxy derivatives with hydrogen bromide in acetic acid (Scheme 156) (72JOC1867). 

Unlike hypoxanthin-l-ol, xanthin-l-ol is precluded from N1 to C2 oxygen transition, but instead undergoes an N1 to N3 hydroxy group translocation. ... 

The purine group of alkaloids includes the vegetable alkaloids caffeine, theobromine, theophylline and the animal alkaloids xanthine, hypoxanthine, guanine and adenine. The most common substance which is a purine compound is uric acid, but, though directly related to the alkaloids given above, it is not itself usually considered as an alkaloid. The constitution of uric acid has been fully considered (Part I, p. 442). It is the tri-hydroxy derivative of a substance known as purine which is the mother substance of the purine alkaloids also. 

Hydroxy-9-(/3-D-riboturanosyl)adenine 9-(/3-D-Ribofuranosyl)hypoxanthine A/ -(/3-D-Ribofuranosyl)-4,6-dimethylimidazof 1,2-a ]purine 1 -Methylisoguanosine... 

Useful antiviral properties were shown by 2-amino-9-(2-hydroxy-ethoxy)methyl-8-azapurin-6-one, the azapurine analog of the purine antiviral drug acyclovir, which is much used in treating human herpes. 9-(2-Hydroxy-4-hydroxymethylcyclopentyl)-8-azaadenine and -hypoxanthine were found to be potent inhibitors of herpes simplex virus (type 1 only) in vitro. 

Xanthine oxidase is a rather nonspecific enzyme it not only catalyzes the oxidation of hypoxanthine and xanthine, but also the conversion of adenine to 2,8-dihydroxyadenine (B23, K9) as well as the oxidation of many unusual purines, such as 2-azaadenine (S14). It also acts on xanthopterin (K4), and catalyzes the oxidation of a variety of aldehydes and NADH. Several pterins, notably 2-amino-4-hydroxy-6-formyl- (K3), 2-amino-4-hydroxy-6-carboxy-, 2-amino-4-hydroxy-, and 6-hydroxymethyl- (P3) pterins, inhibit xanthine oxidase. A variety of purines are both substrate and inhibitor of the enzyme. Antabuse (tetraethylthiuram disulfide) has a considerable inhibitory effect on xanthine oxidase in rat... 

AI3-52242 1,7-Dihydro-6H-purin-6-one EINECS 200-697-3 HX 6-Hydroxypurine 6-Hydroxy-1H-purine Hypoxanthine Hypoxanthine enol NSC 14665 6-Oxopurine 3H-Purin-6-ol Purin-6-ol 9H-Purin-... 

At the present time, we just report some experimental results of a study on the mechanism of action of allopurinol (U-hydroxy-pyrazolo (3, -d ) pyrimidine) and thiopurinol k thiopyrazolo (3, d) pyrimidine) on de novo biosynthesis of uric acid. In this present work, we have compared effect of alio and thiopurinol on oxypurine (xanthine and hypoxanthine) urinary excretion with their rate of synthesis of ribonucleotides in vitro by erythrocyte hemolysate in some particular enzymatic deficiencies (hypoxanthine-guanine phosphoribosyltransferase HGPRT, adenine phosphoribosyl-transferase APRT and xanthinuria). 

We have given allopurinol and thiopurinol to a xanthinuric man and in this communication we report on the urinary excretion amount of U-6 dihydroxy PP oxipurinol, or i+-thio-6-hydroxy PP oxithiopurinol and the concomitant values of xanthine and hypoxanthine. 

Hypoxanthine Purine 6-Hydroxy Inosine Inosine S -phosphate, inosinic acid, IMP... 

Water soluble nucleic acid analogs were prepared by grafting uracil, thymine, 5-fluorouracil, hypoxanthine, cytosine, and adenine derivatives containing a hydroxy group onto linear poly(ethyleneimine). These polymers contained about 90 unit% of the nucleic acid bases, and were easily soluble in water at neutral pH resign. The analogs were found to form complementary polymer complexes with each other and with polynucleotides. The interaction study was made on these polymers, and with polynucleotides poly(uridylic acid) poly(U), poly(adenylic acid) poly(A), poly(inosinic acid) poly(I) and poly(cytidylic acid) poly(C) in water. They were found to form polymer complexes with polynucleotide by specific base-base interaction in aqueous solution. 

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