Purine molecular structure

Several V02+ complexes with nucleotides have been prepared by the addition of aqueous VOSO4 to an aqueous solution of the nucleotide.928 The compounds were formulated as [V0L] nH20 with a suggested polymeric structure. As in the case of the complexes with the purines (191)-(193), further work is needed to sort out the molecular structure of these compounds. 

The 15N chemical shifts as well as the coupling constants Jh.isn in the bases, and related compounds have not been interpreted theoretically. On the other hand, the magnitude of the coupling constants has been predicted from the molecular structure with reasonable accuracy by means of CNDO/2 calculations for pyrimidine, pyridine, or pyra-zole.543 We can expect that a similar prediction of the spin-spin coupling constants may be made for the pyrimidine and purine nucleic acid bases. 

The crystal and molecular structures of 2-substituted 8-azahypoxanthine derivatives 63 have been determined from X-ray data using MoXa radiation. The propoxy group has a strong intramolecular hydrogen bond to N-l of the purine, and that in turn led to a planar compound. The 2-propoxyphenyl and N-methyl-iV-isopropylsulfonyl derivatives are present as the N-9-H tautomers, but the propylsulfonyl compound exists as the... 

Fig. 9.5 The molecular structures of DNA and RNA components the purine bases adenine and guanine, the pyrimidine bases cytosine, thymine and uracil and the structure of riboso-monophosphates.

One of a number of basic compounds found in living matter and having a purine-type molecular structure. See adenine base pair guanine hypoxanthine xanthine uric acid caffeine theobromine. 

Applications to cis-Bis(purine)Ft(II) Complexes. There are presently available a large number of cis-bis(N(7)-bound purine base)Ft(II) complexes whose molecular structures have been determined by X-ray diffraction techniques. For the most part, the nucleobase in these systems is a 6-oxopurine derivative (7). Figure 3 presents conformational drawings for three of these complexes the ci -[Pt(en)(1,3,9-trimethyIxanthine)2] " cation (35) the [Pt(en)(guanosine)2] " cation (36) and [Pt(tn)(Me-5 -GMP2)] ... 

Figure 9 illustrates better the influence of pH and molecular structure on the adsorption of 5-triazines by clay and organic matter. Maximum adsorption occurred near the pKa of each compound, suggesting that basicity was a significant factor in their adsorbability by particulate matter. Adsorption of other basic molecules by cation exchange adsorbents, including atrazine by a carboxyl resin (118), amitrole by mont-morillonite (84) and organic matter (83), and purines and pyrimidines by montmorillonite (119), exhibit similar responses. 

Molecules of imidazopyridines 1 and 2 (IP) are built from imidazole and pyridine nuclei that have no common nitrogen atom. This distinguishes imidazopyridines 1 and 2 from imidazo[l,2-a]pyridine 2 and imidazo[l,5-a]pyridine 6. The latter two have little in common with purine in terms of molecular structure and chemical properties (66JOC1295, 67JOC2430). Consequently, imidazopyridines 5 and 6 are not analogues of purine and are not considered here. 

In this sequence, the pKa of IbP 1 is placed almost exactly between those for purine 3 and benzimidazole 4, and IcP 2 is somewhat closer to purine. These ionization constants give some insight into the influence of the fused rings on the acidity of the imidazole NH. Imidazo[4,5-b]pyridines, and imidazo[4,5-c]-pyridines have more in common with purine in terms of molecular structure and chemical properties than with benzimidazole. 

The relationship between molecular structure of the pigments and of tri-oxy-purine has been discussed and also their possible role in stone formation, as far as uric acid lithiasis is concerned. 

Fischer, Hermann Emil (1852-1919) German organic chemist who discovered the molecular structures of sugars, including glucose, found the structure of purines, isolated and identified amino acids, and worked on the structure of proteins. He received the Nobel Prize in chemistry in 1902 for his work on sugars and purines. 

Zelnik, R., Haraguchi, M., Matida, A.K., Lavie, D., Frolow, F., and Weis, A.L. (1986) X-ray molecular structure of caissarone, a novel purine derivative from the sea anemone Bunodosoma caissarum Correa./, Chem. Soc. Perkin Trans. I, 2051-2053. 

Figure 6 Molecular structure of a NAMI derivative-Ru(IH) adduct (XRD) of formula RuCl H20XLa) containing a model purine nucleobase the important of intramolecular hydrogen bonding stabilization is indicated (See page I of color insert.)...

Birds excrete nitrogen as uric acid Uric acid is a purine having the molecular formula C5H4N4O3 it has no C—H bonds Write a structural formula for uric acid... 

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