•A polyvinyloxazolium perchlorate was prepared by acidification of a polyvinyloxazole.•A polyvinyloxazolium perchlorate catalyzes Vorbrüggen-type N-glycosylations.•A polyvinyloxazolium perchlorate works as a heterogeneous catalyst.A solid-supported acidic oxazolium perchlorate was investigated as a heterogeneous catalyst in N-glycosylation reactions using silylated modified pyrimidines and an acylated ribose or glucose to afford the corresponding pyrimidine nucleosides. This salt is a nonhygroscopic and stable powder whose activity is comparable to that of 2-methyl-5-phenylbenzoxazolium perchlorate. A reaction with this polymer catalyst can be conducted on a gram scale. Reusability of the solid-supported catalyst was also investigated.Download high-res image (105KB)Download full-size image

Novel ribonucleoside 3′,5′-cyclic monophosphorodithioates were synthesized by a combination of the phosphoramidite and phosphotriester methods. These include uridine 3′,5′-cyclic monophosphorodithioate (cUMPS2), cytidine 3′,5′-cyclic monophosphorodithioate (cCMPS2), and guanosine 3′,5′-cyclic monophosphorodithioate (cGMPS2). In addition, 2,6-diaminopurine ribonucleoside 3′,5′-cyclic monophosphorodithioate (cDAPMPS2) was synthesized via the O6-amination reaction of the O6-sulfonylated guanosine derivative.

Adenosine 3′,5′-cyclic monophosphorodithioate (cAMPS2), which has two exocyclic sulfurs directly attached to phosphorus, was synthesized from adenosine phosphoramidite by intramolecular cyclization employing the phosphotriester method as a key step.

Nucleosides that consist of base and sugar moieties can adopt two main conformations, syn and anti, about the glycosidic bond. We have investigated the conformational properties of guanine nucleosides in the gas phase by using laser desorption combined with IR–UV double resonance spectroscopy. In guanosine, syn conformation is preferred as a result of internal hydrogen bonding between the 5′-OH group of the sugar and the N3 site of the guanine moiety. We have therefore employed a chemically modified nucleoside 5′-O-ethylguanosine, in which possible glycosyl bond conformations are restricted upon ethylation of the 5′-OH group. The result shows that anti conformer is stabilized by the formation of hydrogen bonding involving the 2′-OH group.Keywords: glycosidic bond; guanine nucleoside; IR−UV double resonance spectroscopy; laser desorption; syn and anti conformers;

We show that intact neutral molecules of guanosine 5′-monophosphate can be vaporized by laser desorption when its phosphate group is esterified. The UV and IR spectroscopic measurements of this nucleotide reveal the existence of a novel internal hydrogen-bonding conformation of the phosphate group and guanine moiety.

We show that intact neutral molecules of guanosine 5′-monophosphate can be vaporized by laser desorption when its phosphate group is esterified. The UV and IR spectroscopic measurements of this nucleotide reveal the existence of a novel internal hydrogen-bonding conformation of the phosphate group and guanine moiety.