Guanosine derivatives

A phosphitylation instead of an azole transfer occurred in the reaction of a guanosine derivative with phosphorous diester tetrazolide (diethoxytetrazolylphosphine) [2003,[2013... 

The two O -alkylated guanosine derivatives (117) shown in Figure 28, do not demonstrate a perpendicularity of hydrocarbon and base, presumably because the hydrocarbon is much smaller. However, again the nucleoside has the syn-conformation. This perpendicularity, however, is found for the acetylamino fluorine derivative. 

Gottarelli and co-workers have prepared apolar guanosine derivatives 71 and 72 for the study of the above-mentioned processes in organic solvents. In... 

Several natural and synthetic helical macromolecules such as DNA, polypeptides, and polyisocyanates form, in the appropriate solvent, cholesteric meso-phases. Also self-assembled supramolecular systems formed by guanosine derivatives 2 and 3 (G-wires), which are essentially four-stranded helices (Figure 7.8), behave in a similar way.35... 

Inosine 5 -(a-D-glucopyranosyl pyrophosphate) (50) was obtained by use of the pyrophosphorylases, effective for the respective guanosine derivative, from animal tissues,50 pea,223 or Arthrobacter vis-cosus.218 The enzymic synthesis of the a-D-glucopyranosyl pyrophosphate esters of 2 -deoxyuridine223 and 2 -deoxyadenosine216 has also been described. 

Figure 8.3.4. Quadruplets of guanosine derivatives (left) forming a channel with alkaline metal ions.

Acyclovir (Figure 49-2) is an acyclic guanosine derivative with clinical activity against HSV-1, HSV-2, and VZV, but it is approximately 10 times more potent against HSV-1 and HSV-2 than against VZV. In vitro activity against Epstein-Barr virus (EBV), cytomegalovirus (CMV), and human herpesvirus-6 (HHV-6) is present but weaker. 

Shetlar MD, Horn K (1987) Mixed products of thymine and cysteine produced by direct and acetone-sensitized photoreactions. Photochem Photobiol 45 703-712 Sheu C, Foote CS (1995a) Reactivity toward singlet oxygen of a 7,8-dihydro-8-oxoguanosine ( 8-hydroxyguanosine ) formed by photooxidation of a guanosine derivative. J Am Chem Soc 117 6439-6442... 

Lyotropic (in solvent) cholesteric mesophases have been observed for self-assembled guanosine derivatives. In water, the compounds shown in Fig. 10 generate left-handed columnar aggregates [91]. When the concentration is sufficiently high, cholesteric phases are formed which also have a left-handed twist, as determined by CD spectroscopy. The same tetrameric motif is present in the lyomesophases formed by more lipophilic guanosine deriva-... 

Fig.10 Guanosine derivative tetramers that form lyotropic cholesteric phases [91]...

Sheu, C. and Foote, C.S. (1993) Endoperoxide formation in a guanosine derivative. Journal of the American Chemical Society, 115 (22), 10446-10447. 

The preparation of 2-hydroxy-3 -pyridinecarboxaldehyde and its 6-acetamido derivative, and their condensation with Fischer s base to give the corresponding spiropyridopyrans have been described. The acetamido spiro compound selectively recognizes guanine, which traps the open colored form by triple hydrogen bond complementarity, thus signaling the presence of guanosine derivatives.79... 

Davis JT, Spada GP (2007) Supramolecular architectures generated by self-assembly of guanosine derivatives. Chem Soc Rev 36 296-313... 

Fig. 9 (a) Reversible synthesis of a bisiminoboronate-guanosine derivative from guanosine and a bisiminoboronic acid, (b) Dynamic polymeric networks based on reversible boroxine formation, (c) Formation of a macrocycle in a [4 + 4 + 2] condensation via simultaneous reversible formation of imine bonds and boronic esters... 

The evolutionarily conserved Moco biosynthetic pathway consists of three steps (Scheme 1) (1) the conversion of a guanosine derivative (probably guanosine triphosphate) into sulfur-free Precursor Z via insertion of C-8 between the ribose C-2 and C-3 atoms, (2) sulfurization and transformation of Precursor Z into MPT, catalyzed by MPT-synthase, and (3) metal incorporation through chelation of the dithiolene moiety. Additional steps are involved in the attachment of a nucleotide to generate the dinucleotide forms found... 

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