Nitrogen Glycosylation Reactions Involving Pyrimidine and Purine Nucleoside Bases with Furanoside Sugars

Defining a process operating window for the synthesis of 5-methyluridine by transglycosylation of guanosine and thymine

“…Preparation of 5-methyluridine and derivatives by chemical routes, for example from silylated thymine and protected 1-O-acetylribofuranosides, suffers from several disadvantages. These include a large number of process steps, usually involving cycles of protection and deprotection, low yields and low selectivities that result in a mixture of isomers (Wilson and Liotta, 1990;Wilson et al, 1995). An alternative to these methods is preparation of 5-MU using the biocatalytic process of transglycosylation (Hori et al, 1989a(Hori et al, ,b, 1991aIshii et al, 1989).…”

A ring-closing metathesis based synthesis of bicyclic nucleosides locked in S-type conformations by hydroxyl functionalised 3′,4′-trans linkages

“…Standard Vorbrüggen type coupling of thymine to this substrate gave exclusively the b-nucleoside 19 in a high yield due to anchimeric assistance from the 2 0 -O-acetyl group. 40,41 This was confirmed by the large coupling constant 3 J H1 0 H2 0 ¼8.5 Hz. A RCM reaction using the same catalyst as before afforded smoothly the bicyclic nucleoside 20 in 90% yield.…”

A convenient synthesis of 2′,3′‐dideoxyinosine‐13C5 and related 2′,3′‐dideoxyadenosine‐13C5

“…2 The downside to our strategy is the requirement for a group which would potentially steer a b-face glycosylation to provide the b-anomer downstream in our transformation sequence. 4 Such useful synthon 5, bearing a-phenylselenyl substitution in the ribonolactone, was synthesized from (S)-5-[ 13 C 5 ]2,3-dideoxyribonolactone 1 as shown in Scheme 1. The silyl ether 2, which formed by routine protocol, was reacted with lithium bis(trimethylsilyl)amide to give an enolate that was trapped as the trimethylsilyl enol-ether.…”