Halogeno-sugar Nucleosides

A convenient synthesis of 5 -deoxy-2-fluoroadenosine from guanosine has been reported. Ring-opening of l-(2,3-anhydro-P-D-lyxofuranosyl)-cytosine and -uracil with ammonium bromide, iodide, azide, and thiocyanate in refluxing ethanol has been used to prepare l-(3-deoxy-3-halogeno-P-D-arabinofuranosyl)- 

Keto-nucleosides and Nucleosides containing Uronic Acid Components 

R = Tr) decomposed to thymine and the enone (611) in pyridine or during chromatography on silica gel. N.m.r. measurements have indicated that l-(6-deoxy-2,3-0-isopropylidene-a-L-/yxo-hexopyranosyl-4-ulose)thymine adopts a conformation, while 9-(6-deoxy-a-L-/yxo-hexopyranosyl-4-ulose)theo- 

A transglycosylation reaction involving iV -benzoyl-iV ,9-bis(trimethylsilyl)-adenine and a suitably protected uracil polyoxin C has been used in preparing the adenin-9-yl analogue (615) of the nucleoside skeleton of the polyoxin antibiotics, which contain a labile 5-amino-5-deoxy-p-D-allofuranosyluronic acid residue.  

The synthesis of analogues of the octosyl acids and of derivatives of 5-fluoro-0 -(P-D-glucopyranosyluronic acid)uracil are mentioned in Chapters 15 and 3, respectively. 

Mizuno, Y. Watanabe, K. Ikeda, and J. A. McCloskey, Chem. and Pharm. Bull. (Japan), 1975, 23, 1411. 

Reagents i, MetC(OAc)C01 ii, MeONa-MeOH lii, NaNsj iv, Hj-Pd v, dihydropyran-H+ 

3 -0-Methoxyethylideneadenosine reacted with pivalyl chloride in refluxing pyridine to give a mixture containing mainly (469) and (470), as well as the 0-(4,4-dimethyl-3-pivaloxypent-2-enoyl)(Dmpp) derivatives (471 = Cl) and 

3 -Deoxy-3 -fluorouridine has been synthesized in four steps from 5-O-benzyl-3-deoxy-3-fluoro-D-arabinofuranose, but it did not inhibit RNA synthesis in vitrol-(6-Deoxy-6-fluoro- -D-glucopyranosyl)thymine has been prepared by a direct displacement on a corresponding nucleoside 6 -sulphonate with fluoride ion, whereas l-(6-deoxy-6-fluoro-j3-D-gaIactopyranosyl)thymine was obtained via condensation of l,2,3,4-tetra-0-acetyl-6-deoxy-6-fluoro-/3-D-galactopyranose with 5-methyl-2,4-bis(trimethylsilyioxy)pyrimidine.  

Kowoilik, K. Gaertner, and P. Langen, J. Carbohydrates, Nucleosides, Nucleotides, 

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Treatment of 5-deoxy-5-halogeno nucleosides of adenine and uracil with trimethylamine yielded the corresponding 5-deoxy-5-trimethylammonium salts, whose interaction with anionic polynucleotides was then examined. Various A -alkyl, A -cycloalkyl, and iV-alkaryl derivatives of 3-amino-3-deoxy-and 3, 5 -diamino-3, 5 -dideoxy-adenosine have been prepared from the amino-sugar nucleosides the 3 -benzylamino derivative gave the unusual oxazolidine derivative (52). ° ... 

Reference to nucleosides containing halogeno-sugars is made in... 

Halogeno-sugar and Amino-sugar Nucleosides Thionucleosides... 

The synthesis of radiolabelled halogeno-nucleosides is included in Chapter 20, while the use of halogeno-sugars in synthesis is referred to in Chapters 12 and 13. 

D-lyxopyranosyl nucleosides with hydrogen halides to give the 3 -bromo- or 3 -chloro-3 -deoxy-nucleosides (406), or a mixture of the 2 - and 3 -fluoro-deoxy-nucleosides (407). 9-(3-Deoxy-3-iodo-)3-D-xylofuranosyl)hypoxanthine has been synthesized and converted into 3 -amino-3 -deoxy- and 3, 4 -unsatu-rated nucleosides as shown in Scheme 138. Both l-(2-deoxy-2-fluoro- and 2-chloro-2-deoxy-j8-D-arabinofuranosyl)cytidine have been prepared from the corresponding halogeno-sugar derivatives by standard methods (see Schemes 43 and 46). ... 

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