Uridine analogs

Townsend and coworkers (80JCS(P1)1853) prepared several ribofuranosyl nucleosides of the thieno[2,3-d]pyrimidine ring system by condensation of the silylated base with l-O-acetyl-2,3,5-tri-0-benzoyl-j3-D-ribofuranose in 1,2-dichloroethane in the presence of tin(IV) chloride (Scheme 101). These nucleosides are analogs of cytidine. Uridine analogs have been prepared from thieno[2,3-rf]pyrimidine-2,4-diones. 

Acryloyl isocyanates, reaction with amino-sugars, uridine analogs from, 55, 139 A-Acyldehydroaminoacids, addition of nucleophiles, 57, 230 Acylhydrazones, a/3-unsaturated, cycloadditions, 57, 14 A-Acyliminium (ions), generation from alkylidenepiperazine-2,5-diones, 57, 230... 

Methylated uridine analogs can be generated using related methods, such as treatment of uridine with NaH and Mel (Fig. 2d, steps i, ii) (13) to give m U or conversion to 2 -0-methyluridine (Um) through an anhydronucleoside intermediate and opening by the appropriate nucleophile (18). 

The specificity of rat-muscle glycogen-UDPglucosyl transferase has been examined by Goldemberg. A marked difference from starch-UDPglucosyl transferase is that adenosine 5- D-glucosyl pyrophosphate) is only 50% as effective as the uridine analog. In contrast to the rabbit-muscle enzyme, maltoheptaose (and maltosaccharides of DP 4, 5, 6, and 8) will slowly act as acceptors of low efficiency. Maltose and malto-triose are very inefficient acceptors, and at concentrations of 0.64 and... 

Extension of this type of work has led to the production of related 4,5-unsaturated furanosyl nucleosides, as follows (i) the uridine analog (68, R = uracilyl, R = H)127 (prepared by deacetylation of the 2, 3 -diacetate) (ii) the 2, 3 -isopropylidene acetal of this nucleoside128 (prepared by treatment of 2, 3 -0-isopropylidene-5 -0-p-tolyl-sulfonyluridine with potassium ferf-butoxide in ferf-butanol, or, in lower yield, from the 2,5 -anhydronucleoside derivative), and (iii) the... 

A novel cyclization reaction of a C-6 substituted uridine analog an entry to 5,6-dialkylated uridine derivatives, Tetrahedron Lett. 30 7005 (1989). 

Figure 10.18 Labeling of the 5-position of uridine analog with 3-azido-7-hydroxycoumarins.

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