| Abstract: | Nucleotides. X. Synthesis and properties of dinucleoside monophosphates with 2′-deoxyadenosine and 1-(2′-deoxy-β-D -ribofuranosyl)-lumazines as building blocks The synthesis of various dinucleoside monophosphates 16--20 consisting of 2′-deoxyadenosine and 1-(2′-deoxy-β-D -ribofuranosyl)-lumazines via the triester approach is described. The fully protected phosphotriesters 6--10 as well as the partially deblocked intermediates 11--15 have also been isolated and characterized by physical means. Intramolecular interactions in 16--20 have been investigated by the determination of the hypochromicities and CD. spectra revealing a more or less distinct stacking effect in dependence of the 6,7-substituents in the lumazine moiety as well as the polarity of the internucleotidic linkage. Enzymatic degradations of the dinucleoside monophosphates with snake venom and spleen phosphodiesterase are depending strongly on various structural features indicating a much lower substrate specificity especially in presence of 6,7-diphenyl-lumazine as an aglycone with the latter enzyme. |
