Harold C. Jarrell

Carbon-13 Nuclear Magnetic Resonance Spectra of Some Dendroketose and Other Furanose Derivatives

The carbon-13 n.m.r. spectra of derivatives of the branched-chain sugars apiose and dendroketose, and of other furanose sugars, are reported. The study has permitted assignment of the configuration at the branching carbon atom and at the anomeric center in the dendroketose derivatives.

Syntheses related to dendroketose

Abstract A stereospecific synthesis of l -dendroketose [4-C-(hydroxymethyl)- l -glycero-pentulose] has been attempted starting from 2,3:4,5-di-O-isopropylidene-aldehydo- d -arabinose (1). A key step in the proposed route is the O-debenzoylation of 1,5-di-O-benzoyl-4-C-(benzoyloxymethyl)-3,4-O-isopropylidene- l -glycero-pentulose (6). However, treatment of 6 with sodium methoxide in methanol at 0° afforded 3,4-O-isopropylidenedendroketose as the dl modification. The racemization process was investigated by deuterium-exchange studies.

Syntheses related to the octodiose in apramycin

Abstract a synthesis of 3- O -benzyl-6-deoxy-1,2:7,8-di- O -isopropylidene- l -, glycero - ( 17 ) and - d - glycero - l - altro -octodifuranose ( 20 ) has been achieved starting with 1,2- O - isopropylidene-5- O - p -tolylsulfonyl-β- d -arabinofuranose ( 6 ). Reaction of 3- O -benzyl-1,2- O -isopropylidene-β- l - arabino -pentodialdo-1,4-furanose ( 9 ) with allylmagnesium bromide afforded the epimeric 3- O -benzyl-6,7,8-trideoxy-1,2- O -isopropylidene-α- d - galacto - ( 11 ) and β- l - altro -oct-7-enose ( 12 ); the stereochemistry at C-5 of the compounds was established by the degradation of 12 to the known 2-deoxy- d - ribo -hexitol ( 24 ).Olefin 12 gave S-azido-3- O -benzyl-6,8-dideoxy-1,2- O -isopropylidene- l - glycero -( 14 ) and - d - glycero -β- l - altro -octofuranose ( 15 ), which were photolyzed to the dialdose derivatives 16 and 19 , respectively. Compound 16 was converted into 3- O -benzyl-6- deoxy-1,2:7,8-di- O -isopropylidene- l - glycero - l - altro -octodifuranose ( 17 ) and subsequently into a mixture of methyl glycosides. Similarly, 19 was converted into the d - glycero analog ( 20 ) of 17 . The stereochemistry at C-7 in derivatives 17 and 20 has been tentatively assigned bv use of n.m.r spectroscopy.

Oxidation of a branched-chain alditol by Acetobacter suboxydans: A stereospecific synthesis of l-dendroketose

A synthesis of L-dendroketose (5) has been achieved by microbiological oxidation by Acetobacter suboxydans of the branched-chain alditol 2-C-(hydroxy-methyl)-D-erythro-pentitol (4). Treatment of the oxidation product with acetone, copper(II) sulfate, and sulfuric acid afforded the two di-O-isopropylidene-L-dendro-ketose derivatives 6 and 7. Assignment of configuration at the branching carbon atom (C-4) and at the anomeric center in 6 and 7 was made on the basis of the carbon-13 magnetic resonance spectra of these derivatives.

Synthesis of nucleosides by direct replacement of the anomeric hydroxy-group

A novel synthesis of purine nucleosides of aldoses and ketoses has been developed, by a method involving treatment of an appropriately protected sugar derivative having a free anomeric hydroxy-group with 6-chloropurine, diethyl azodicarboxylate, and methyldiphenylphosphine.

CARBON-13 NUCLEAR MAGNETIC RESONANCE SPECTRA OF SOME DENDROKETOSE AND OTHER FURANOSE DERIVATIVES

The carbon-13 n.m.r. spectra of derivatives of the branched-chain sugars apiose and dendroketose, and of other furanose sugars, are reported. The study has permitted assignment of the configuration at the branching carbon atom and at the anomeric center in the dendroketose derivatives.