- Studies of the Tautomerism of Purine and the Protonation of Purine and Its 7- and 9-Methyl Derivatives by Nitrogen-15 Nuclear Magnetic Resonance Spectroscopy
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The nitrogen-15 NMR shifts of purine and its 7- and 9-methyl derivatives were measured at the natural-abundance level as a function of pH.The results made it possible for both the sites and magnitudes of protonation of purine and its derivatives to be determined.A semiquantitative determination was made of the position of the N7H-N9H tautomeric equilibria of purine in both water and dimethyl sulfoxide.
- Gonnella, Nina C.,Roberts, John D.
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- New Synthesis of Fused Pyrimidine Derivatives via ortho-(Isocyanomethyl)nitroaromatic Compounds
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An efficient synthesis of functionalized fused pyrimidine derivatives from the respective ortho-(isocyanomethyl)nitroarenes is described.Hydrolysis of the isocyano group in the title isonitriles followed by catalytic reduction of the nitro group and subsequent cyclocondensation of the diamine formed with orthoesters leads to the final products.
- Ostrowski, Stanislaw
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p. 180 - 187
(2007/10/03)
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- Methylathion of Heterocyclic Compounds Containing NH, SH and/or OH Groups by Means of N,N-Dimethylformamide Dimethyl Acetal
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Methylations of heterocyclic systems, such as benzimidazole, naphthimidazole, imidazopyridine, purine, pyridine, pyrimidine, pyridazine and s-triazolopyridazine, which bore SH, NH and/or OH groups, were carried out with dimethylformamide dimethyl acetal to give the corresponding S-, N- and/or O-methyl derivatives in high yields.Selective methylation of some compounds containing both SH and NH groups took place to give first the S-methyl and subsequently the S,N-dimethyl derivatives.No side reactions, such as C-methylation, were observed.
- Stanovnik, Branko,Tisler, Miha,Hribar, Alenka,Barlin, Gordon B.,Brown, Desmond J.
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p. 1729 - 1738
(2007/10/02)
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