2- deoxy- 3-D-ribofuranose

A number of syntheses of acyclic chain extended compounds have been reported this year. 2-Deoxy-D-glucose has been elaborated to 213 a precursor to the C14-C24 section of tautomycin, and a synthesis of the C1-C12 fragment 216 of amphotericin B utilizes a Wittig coupling of two carbohydrate components, the 3-deoxy-D-ribofuranose derivative 215 and the galactose-derived 214.91... 

The facile conversion of C-nitromethyl- into aldehydo-groups with aqueous titanium (III) chloride has provided a convenient route to several C-formyl sugars, which can be isomerized to the thermodynamically favoured isomers with methan-olic sodium methoxide (Scheme 70). Conventional reactions have been used to obtain the 3-C-acetamidomethyl-3-deoxy-D-ribofuranose derivative (388) from l,2-0-isopropylidene-5-0-trityl-a-D-er> thro-pentofuranos-3-ulose, and the 6-benzoate (389) of 3-deoxy-l,2-0-isopropylidene-3-C-nitromethyl-a-D-allo-furanose has been converted, by a conventional chain-shortening procedure, into... 

The synthesis of 3-C-acetamidomethyl-3-deoxy-D-ribofuranose and related branched-chain sugars described by Abdel-Rahman (see Vol. 11, p. 124) has been claimed to be a copy of an earlier publication by Lourens (see Vol. 3, p. 122). 

D-Ribofuranose-type phospha sugars 50 (R=OH, Et, and Ph) and 2-deoxy-D-ribofuranose analogues 51 (R=OH and Me) in Fig. 3 have been prepared via longer reaction pathways by a similar ring closing intramolecular addition reaction of a P - H group to an aldehyde of sugars shown in Scheme 14 [17-20]. 

In 1970, 1 was prepared by direct glycosylation of the silylated 5-azacytosine with acylated 1-halo sugars, but the yields were very low.20 In this procedure, 1,3,5-tri-O-acetyl-2-deoxy-D-ribofuranose (9) was converted into 3,5-di-0-acetyl-2-deoxy-D-ribofuranosyl chloride (10).21 The trimethylsilyl derivative of 5-azacytosine (11),22 prepared from 4-amino-6-pyrimidine by treatment with hexamethyldisilazane, was then allowed to react with intermediate 10 in acetonitrile over 7 days to give a mixture of anomers of l-(3,5-di-(9-acetyl-2-deoxy-D-ribofuranosyl)-5-azacytosine (12) in 10% overall yield. The anomeric mixture was treated with ethanolic ammonia to remove the acetyl groups. The resulting a and p anomers were separated by a combination of fractional crystallization and preparative layer chromatography on silica gel to give pure decitabine (1) and its a-anomer 13 in 7% and 52% yield, respectively. 

Deoxy-D-ribofuranose 1 -(Cyan-methyl)- 2,3-O-isoptopyliden-E21e, 4833 (OH - CH2-CN) Essigsaure Cyclohexyliden-nitro- -ethylester X/1, 63... 

Deoxy-D-ribofuranose 2,3-0-lsopropyliden-l-(methoxycarbo-nyl-methyl)- E21e, 4833 (OH -> CH2-COOR)... 

For synthesis of nucleosides, methyl 4-acetamido-2,3-di-0-benzoyl-4-deoxy-a-D-ribopyranoside (198c), obtained from 198a, was trans-formed by acetolysis into 4-acetamido-l,5-di-0-acetyl-2,3-di-0-benzoyl-4-deoxy-D-ribofuranose (199b). Either with preliminary treatment with hydrogen chloride in acetyl chloride, or directly, in the presence of titanium tetrachloride, 199b gave with chloromercuri-(6-... 

In this synthesis, a mixture of tri-0-acetyl sugars was obtained, from which the desired 2-acetamido-l,3,5-tri-0-acetyl-2-deoxy-D-ribofuranose was isolated. Another sugar, assumed to be the isomeric 2-acetamido-l,3,4-tri-0-acetyl-2-deoxy-D-ribo-pyranose, was also isolated, converted to the O-acylglycosyl chloride, and allowed to react with chloromercuri-6-chloropurine. Deblocking with dimethylamine gave a nucleoside thought to be 9-(2-acetamido-2-deoxy-oi-D-ribopyranosyl)-JV ,W -dimethyl-adenine. 

Aldopentoses also form cyclic hemiacetals. The most prevalent forms of D-ribose and other pentoses in the biological world are furanoses. Following are Haworth projections for a-D-ribofuranose (a-D-ribose) and /3-2-deoxy-D-ribofuranose (j8-2-deoxy-D-ribose) ... 

Various deoxy-sugars have been obtained from halogeno-derlvatlves by reductive displacement reactions. Methyl -deoxy-3-D-threo-hexulofuranoside (15) has been obtained by Raney nickel-hydrazine de-iodination of 3-iodide (16) (see Chapter J) its resistance to hydrolysis by invertase (3-D-fructofuranosidase) demonstrated that not only a 1- and 6-, but also a 4-hydroxy group is necessary for enzyme bonding.5-Deoxy-D-ribofuranose derivatives, and various 5-deuteriated and 5,5-dideuteriated analogues were synthesized from... 

Azido-2,3-0-benzylidene-5-deoxy- -D-ribofuranose treated overnight at room temp, with CrOs - pyridine complex 5 - azido - 2,3 - O - benzylidene - 5 - deoxy - D-... 

The teichoic acids have structures that have a common feature with the nucleic acids. The nucleic acids are polymers composed of D-ribofuranose or 2-deoxy-D-ribofuranose residues joined together by phosphodiester linkages between C-3-... 

Of the four possible 5-deoxy-pent-4-enofuranoses, the D-erythro-isomer was of interest as a potential source of derivatives of L-lyxofuranose. For this purpose, a vinyl ether having the D-en/ hro-configuration has been prepared from derivatives of D-ribose. Condensation of D-ribose with acetone in the presence of methanol, cupric sulfate and sulfuric acid at 30°C., as described by Levene and Stiller(30) afforded a sirupy product consisting mainly of methyl 2,3-O-isopropylidene-D-ribofuranose (40). Treatment of a pyridine solution of the sirup with tosyl chloride... 

C19H24BrN09S 5-0-(p-Bromophenylsulfonyl)-3-deoxy-3-C-(R)-(ethox-ycarbonylformamido)methyl-l,2-0-isopropylidene-a-D-ribofuranose (BDEIRF)284... 

Preparation of 5-(3-benzoylpropionyl)-3-deoxy-3-diisopropoxyphosphinylmethyl-l,2-di-0-acetyl-D-ribofuranose — Reaction of an alkyl bromide in a carbohydrate series with triisopropyl phosphite... 

A solution of 5-0-(3-benzoylpropionyl)-3-deoxy-3-bromomethyl-l,2-di-O-acetyl-D-ribofuranose (2.35 g, 4.89 mmol) in triisopropyl phosphite (17 g, 81 mmol) was heated at 160 to 180°C with exclusion of moisture for 72 h. Volatile materials were removed under reduced pressure, and the residue was purified by chromatography on a silica gel column (48 x 2.7 cm) eluting with chloroform ethyl acetate (1 1). From the 150 to 500 ml eluent, there was isolated the pure 5-(3-benzoylpropionyl)-3-deoxy-3-diisopropoxyphosphinylmethyl-l,2-di-O-acetyl-D-ribofuranose (1.73 g, 68%) as an oil that exhibited IR and NMR spectra and analyses in accord with the proposed structure. 

A stereochemical dependence has been observed for the 5/f,h-i values observed for a number of 3-deoxy-3-C-(fluoromethylene)-l,2 5,6-di-0-isopropylidene-a-D-ribofuranose derivatives n. =... 

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