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Biomedical subjects

L Hough

Publications and source records attributed to L Hough.

33 records · Page 2Linked to original sources
PubMed1975

Some benzylidene acetal derivatives of theophylline nucleosides.

The reaction of some hexopyranosyltheophylline nucleosides with benzaldehyde in the presence of zinc chloride gave the expected benzylidene acetals. Thus, 7-alpha-D-mannopyranosyltheophylline gave the 2',3':4',6'-diacetal as a mixture of diastereoisomers, one of which was isolated. The beta-D-galacto- and beta-D-gluco-pyranosyltheophyllines gave the 4',6'-acetals, which were characterised as 2',3'-diesters. Mild, acidic hydrolysis of 7-(4,6-O-benzylidene-2,3-di-O-mesyl-beta-D-glucopyranosyl)theophylline gave 7-(2,3-di-O-mesyl-beta-D-glucopyranosyl)theophylline, and strongly basic hydrolysis gave 7-(2,3-anhydro-4,6-O-benzylidene-beta-D-allopyranosyl)theophylline. Ring-opening of this 2',3'-epoxide with iodide anion afforded mainly 7-(4,6-O-benzylidene-2-deozy-2-iodo-beta-D-altropyranosyl)theophylline, which was characterised as the 6'-acetate.

Benzylidene Compounds↗
PubMed1966

Some observations on the periodate oxidation of amino compounds.

Various aliphatic and aromatic amines are oxidized by sodium metaperiodate and these reactions have been studied quantitatively in acidic, unbuffered and basic media. Significant differences have been observed between the behaviour of aliphatic and aromatic amines. Certain compounds also behaved differently under acidic and basic conditions. These reactions are related to the periodate oxidation of amino acids and, from observations on a number of glycine derivatives, a reaction mechanism is proposed for this process.

Amines↗
PubMed1966

Some further studies on the synthesis of glycopeptide derivatives: 2-acetamido-2-deoxy-beta-D-glucopyranosylamine derivatives.

1. The isolation, characterization and properties of two by-products in the preparation of 2-acetamido-3,4,6-tri-O- acetyl-2-deoxy-beta-d-glucopyranosylamine are described. They are bis(2-acetamido-2-deoxy-d-glucopyranosyl)amines. 2. An independent synthesis of the bis-glycopyranosylamines is reported and conditions are given for their preparation in high yield. 3. Further improvements are given for the synthesis of 2-acetamido-1-N-(beta-l- aspartyl)-2-deoxy-beta-d-glucopyranosylamine and the alpha-l-aspartyl isomer. 4. The synthesis of 2-acetamido-1-N-acetyl-2-deoxy-beta-d-glucopyranosylamine is described.

Amino Sugars↗
PubMed1965

The biosynthesis of l-rhamnose of plum-leaf polysaccharides.

1. The utilization of d-[1-(14)C]- and d-[6-(14)C]-glucose in the biosynthesis of l-rhamnose units of plum-leaf polysaccharides has been studied. 2. After the precursors had been metabolized in the leaves, polysaccharide fractions were prepared therefrom and the constituent l-rhamnose was isolated and purified. 3. Both the specific activity and the distribution of (14)C along the carbon chain of l-rhamnose from two polysaccharide fractions from each experiment were determined. 4. The results indicated a close affinity between l-rhamnose and pectin, and show that biosynthesis of the 6-deoxyhexose from d-glucose occurs in the main without scission or inversion of the carbon chain. 5. A degradation scheme for l-rhamnose via l-rhamnitol was described which gives the labelling at C-1, C-2+C-3+C-4,C-5 and C-6 on a 0.3millimole scale.

Journal Article↗