Nucleosides acyclic-sugar

The acyclic nucleoside phosphonates (ANPs) can be considered as nucleotide rather than nucleoside analogues, in that, besides the purine or pyrimidine base, they contain an (acyclic) sugar moiety to which a phosphonate is attached. In these nucleotide analogues (Fig. 2), the phosphoric ester grouping (= P-O---C-----) is... 

Synthesis by carbon-carbon bond formation between an acyclic sugar derivative and the benzothiazole ring system has also been utilized for the synthesis of these C-nucleosides. In one report, 2,3-O-isopropylidene-D-glyceraldehyde (61) was coupled with 2-trimethylsilylbenzothiazole to afford the A-nucleoside 185 as an intermediate, which underwent a 1,2-shift of the alditolyl chain to produce the C-nucleoside 186 (85TL5477) (Scheme 55). 

The thieno[3,2-d]pyrimidine system of 367 was constructed onto the acyclic sugar derivative 346. This acyclo C-nucleoside (367) did not inhibit a number of DNA and RNA viruses in cell cultures [91JCS(P1)195] (Scheme 105). 

A trimer oligoribonucleotide bearing a S -amino function, 2 -S -phosphodiester linkages and an acyclic sugar moiety at the 3 -nucleoside position (169) has been prepared and characterised by Pfleiderer and co-workers. 

Cycloaddition of hydrazoic acid to aldononitriles (618) (71MI2 75MI5 79MI13 90MI3) or thermolysis of the 1,1-diazido acyclic sugar derivatives 789 [95JCS(P1)1747] yielded the tetrazole acyclo C-nucleosides 749 (Scheme 218). 

Rosenthal and coworkers [91, 92] have described the TLC of some acylated anhydro-hexitols and heptitols. Wolfrom et al. [93, 94, 95, 96, 97] characterized various derivatives of n-glucosamine and acyclic sugar nucleoside analogs by TLC. The a- and /8-anomers of tri-O-benzoyl-3-0-methyl-n-glucopyranosyl fiuoride have been separated on silica gel H with benzene-acetone (90 -f 10) [98]. 

Homonucleosides have been obtained from 3,4-di-0-acetyl-2,5-anhydro-D-xylose di-isobutyl dithioacetal and from an acyclic-sugar nucleoside (Scheme 125). The first of a series of papers on isonucleosides i.e. nucleosides in which... 

Cadmium carbonate Acyclic-sugar nucleosides N-Thioglycosyl-N-heterocyclics... 

An empirical rule that predicts the sign of the Cotton effect of glycosylated uracil, cytosine, thymine, adenine, and guanine has been developed. The rule is not restricted to pentofuranosyl residues linked to N-1 of pyrimidines and to N-9 of purines, but can be applied to cyclic and acyclic sugars linked to any position on these bases. The c.d. spectra of the double-headed nucleosides 5 -deoxy-5 -(indol-l-yl)- and 5 -deoxy-5 -(6-methylthiopurin-9-yl)-adenosine and -uridine have been reported, and 3-deazapurine nucleosides have been shown to prefer a syn conformation about the iV-glycosidic bond by comparison of their c.d. spectra with those of common nucleosides. ... 

The cyclization of the 2-hydrazino-4-methylquinohne derivatives of sugars 740 by the action of ferric chloride to give the acyclic nucleosides 741 (94MI295) (Scheme 128). 

As it is evident from the chemical strnctnre, acyclovir looks like a nucleoside analog of gnanosine in side chain of which, instead of the traditional cyclic sugar residue a 2-hydrox-yethoxymethyl acyclic side chain is present. Acyclovir possesses antiviral activity with respect to types 1 and 2 of herpes simplex, shingles vims, Epstein-Barr virus, and cytomegalovirns. 

Several examples of the use of (4a) catalyzed cross metathesis of protected allylic sugars, or vinyl substituted heterocycles or vinylated functional groups have been reported. Vinylphosphonate-linked nucleotide dimers were synthesized by cross metathesis using complex (4a), achieving products with E Z ratios of >20 1 in moderate to good yields (equation 17). A metal-mediated route to acyclic nucleosides developed by Agrofoglio and coworkers produced nucleosides in two steps from parent pyrimidines and purines. ... 

A series of conformationally restricted acyclic pyrimidine nucleosides fixing the base-sugar orientation in the anticonformation by forming a carbon bridge between them has been prepared. This was based on the... 

Reaction of sugars with benzamidrazone iodide followed by cyclization with acetic anhydride gave cyclic or acyclic nucleoside analogues of 5-methyl-... 

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