Nucleosides properties

Pyrido[3,4-d]pyrimidine-2,4-dione synthesis, 3, 215 Pyridopyrimidines, 3, 201 iV-alkylations, 3, 206 biological activity, 3, 260-261 1-electron reductions, 3, 207 IR spectra, 3, 204 mass spectra, 3, 204 MO calculations, 3, 204 NMR, 3, 202, 203 nucleophilic substitution, 3, 213 8-nucleosides synthesis, 3, 206 physical properties, 3, 201-205 protonation, 3, 206 radical reactions, 3, 215 reactions with water, 3, 207 reduced... 

Nimodipine, but not other DHPs, is also a potent inhibitor of nucleoside transport with actions similar to known nucleoside transport inhibitors such as dipyr-idamol. It is likely that this mechanism also contributes to the potent vasodilating properties of this DHP. 

Recent developments in DNA/RNA chemical synthesis have allowed us to attach some functional groups covalently to nucleic acids, thus permitting the introduction of a functionality or properties not normally present in the native biomolecule The use of non-nucleosidic linkers is probably the most popular approach for the 5 -terminal modification of chemically synthesized nucleic acid oligonucleotides and a number of such linkers are commercially available. The linker shown in Fig. 2 is designed as a phosphoramidate derivative so that it can be incorporated into the 5 -terminus of the sequence as the last... 

Onidas D, Markovitsi D, Marguet S, Sharonov A, Gustavsson T (2002) Fluorescence properties of DNA nucleosides and nucleotides a refined steady-state and femtosecond investigation. J Phys ChemB 106 11367... 

Gaied NB, Glasser N, Ramalanjaona N, Beltz H, Wolff P, Marquet R, Burger A, Mly Y (2005) 8-vinyl-deoxyadenosine, an alternative fluorescent nucleoside analog to 2 -deoxyribosyl-2-aminopurine with improved properties. Nucl Acids Res 33 1031-1039... 

Our studies showed that i) substitution of an exocyclic amino group of dG is effective in modulating the chemical properties of dG toward one-electron oxidation, and ii) decomposition of the guanine radical cation was effectively suppressed near dphG. These results indicate that dphG is a prototype of nucleosides functioning as an intrinsic antioxidant of duplex DNA toward one-electron oxidation. 

Saito Y, Hanawa K, Kawasaki N et al (2006) Acridone-labeled base-discriminating fluorescence (BDF) nucleoside synthesis and their photophysical properties. Chem Lett... 

Kalek, M., Jemielity, J., Grudzien, E., Zuberek, J., Bojarska, E., Cohen, L., Stepinski, J., Stolarski, R., Davis, R. E., Rhoads, R. E., and Darzynkiewicz, E. (2005). Synthesis and biochemical properties of novel mRNA S cap analogs resistant to enzymatic hydrolysis. Nucleosides, Nucleotides, and Nucleic Acid 24, 615-621. 

Mayer, E., Valis, L., Huber, R., Amann, N. and Wagenknecht, H. A. (2003). Preparation of pyrene-modified purine and pyrimidine nucleosides via Suzuki-Miyaura cross-couplings and characterization of their fluorescent properties. Synthesis 2335-2340. 

The unique properties of oligonucleotides create crosslinking options that are far different from any other biological molecule. Nucleic acids are the only major class of macromolecule that can be specifically duplicated in vitro by enzymatic means. The addition of modified nucleoside triphosphates to an existing DNA strand by the action of polymerases or transferases allows addition of spacer arms or detection components at random or discrete sites along the chain. Alternatively, chemical methods that modify nucleotides at selected functional groups can be used to produce spacer arm derivatives or activated intermediates for subsequent coupling to other molecules. 

Most of this section will be devoted to summarizing information relating to the stability constants reported for complexes of this group of Ca2+-binding ligands. However, we shall precede this main part with a short mention of a few relevant structures. Other properties of calcium phosphates and phosphonates will be mentioned in Sections VIII.B.4 and VIII.D below. An overall view of complexes of nucleosides, nucleotides, and nucleic acids is available (670). 

Table XIX contains stability constants for complexes of Ca2+ and of several other M2+ ions with a selection of phosphonate and nucleotide ligands (681,687-695). There is considerably more published information, especially on ATP (and, to a lesser extent, ADP and AMP) complexes at various pHs, ionic strengths, and temperatures (229,696,697), and on phosphonates (688) and bisphosphonates (688,698). The metal-ion binding properties of cytidine have been considered in detail in relation to stability constant determinations for its Ca2+ complex and complexes of seven other M2+ cations (232), and for ternary M21 -cytidine-amino acid and -oxalate complexes (699). Stability constant data for Ca2+ complexes of the nucleosides cytidine and uridine, the nucleoside bases adenine, cytosine, uracil, and thymine, and the 5 -monophosphates of adenosine, cytidine, thymidine, and uridine, have been listed along with values for analogous complexes of a wide range of other metal ions (700). Unfortunately comparisons are sometimes precluded by significant differences in experimental conditions.

The C-nucleosides are a group of C-glycosylated heterocycles in which the anomeric carbon atom is attached to the heterocycle by a C-C bond. For a number of years after its discovery, pseudouridine1 (1) was the only representative of this class of compound it is found as a minor component in various transfer ribonucleic acids.2 Since 1959, a number of other C-nucleosides have been isolated in rapid succession, mainly from fermentation sources, and have been found to exhibit a variety of interesting biological properties.3 Thus, pyraz-... 

An intramolecular cyclization of a tetrazole-containing nucleoside 64 has been observed by Chu and co-workers <1997JOC7267> (cf. other properties of this compound in Table 3). These authors reported that the 3-OH group on the arabinofuranose ring participates in an addition reaction at position 7 of the tetrazolo[l,5-c]pyrimidine ring to form 65 which is a dihydro derivative of the parent heterocycle. The final structure elucidation has been carried out with the help of the tricyclic tandem mass spectrometry (MS/MS) fragment 66. 

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