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2-Deoxy- d -glucitol and 2-deoxy- d -allitol, both prepared as crystalline polyols from d -erythronolactone, are oxidized by Gluconobacter thailandicus NBRC 3254 to 5-deoxy- d - threo -hexulose [5-deoxy- d -fructose = 5-deoxy- l -sorbose] and 5-deoxy- d - erythro -hexulose [5-deoxy- l -psicose = 5-deoxy- d -tagatose], respectively. d -Tagatose-3-epimerase (DTE) equilibrates 5-deoxy- d -fructose to 5-deoxy- d -psicose and 5-deoxy- l -psicose to 5-deoxy- l -fructose, providing substrates for the preparation of all eight d - and l -5-deoxy aldohexoses by aldose isomerases. This combination of chemical and biotechnological methods allows a concise approach to the synthesis of all twelve 5-deoxy hexoses and further demonstrates the range of deoxy sugar substrates on which DTE is active. NMR studies show that 5-deoxy- d -fructose exists solely as the β-pyranose form whereas both pyranoses of 5-deoxy- d -fructose [α:β. 22:78] are observed. [For the sake of clarity, all ketoses in this Letter are shown in blue, alditols in red and aldoses in purple.]

The Kiliani synthesis on the 4 readily accessible ketohexoses ( d -fructose, d -tagatose, l -sorbose, d -psicose) allows access to 4 diastereomeric 2-C-methyl-aldohexoses (2-C-methyl- d -mannose, 2-C-methyl- d -talose, 2-C-methyl- l -gulose, 2-C-methyl- d -allose) and 4 diastereomeric 2-C-methyl-alditols (2-C-methyl- d -mannitol, 2-C-methyl- d -talitol, 2-C-methyl- l -gulitol, 2-C-methyl- d -allitol). Microbial oxidation of 2-C-methyl- d -mannitol and 2-C-methyl- l -gulitol gave 5-C-methyl- d -fructose; microbial oxidation of 2-C-methyl- d -talitol afforded 5-C-methyl- d -psicose, whereas 2-C-methyl- d -allitol formed 5-C-methyl- l -psicose. Both enantiomers of 5-C-methyl-fructose were equilibrated by d -tagatose-3-epimerase (DTE) with both enantiomers of 5-C-methyl-psicose. These transformations demonstrate that polyol dehydrogenases and DTE act on branched synthetic sugars. Full NMR analyses show that 5-C-methyl- d -fructose is present as the β-pyranose and β-furanose forms in a ratio of 90:10; all pyranose and furanose forms of 5-C-methyl- d -psicose are present in solution. The combination of chemical and biological procedures allows the environmentally friendly generation of a new family of branched monosaccharides.

A Number of commercial peer-to-peer (P2P) systems for live streaming have been introduced in recent years. The behaviour of the popular systems has been extensively studied in several measurement papers. However, these studies have to rely on a “black-box” approach, where packet traces are collected from a single or a limited number of measurement points, to infer various properties of the traffic on the control and data planes. Although, such studies are useful to compared different systems from the end user’s perspective. It is difficult to intuitively understand the observed properties without fully reverseengineering the underlying systems. In this paper, we describe the network architecture of Zattoo, one of the largest production, live streaming providers, in Europe, at the time of writing, and present a large-scale measurement study of zattoo, using data collected by the provider. To highlight we found that even, when the zattoo system was heavily loaded with as high as 20000 concurrent users on a single overlay, the median channel join delay remained less than 2-5 s, and that, for a majority of users, the streamed signal lags over-the-air broadcast signal by more than 3 s.

The efficient isomerization of l-rhamnose [the only cheaply available deoxy hexose] to 1-deoxy-l-psicose, 1-deoxy-d-psicose, 1-deoxy-l-fructose, 1-deoxy-d-fructose, 1-deoxy-l-tagatose, 6-deoxy-l-psicose, 6-deoxy-d-psicose, 6-deoxy-l-fructose, 6-deoxy-d-fructose, and 6-deoxy-l-tagatose is described. The conversion of rhamnose to ten of the sixteen 1- and 6-deoxyketohexoses is accomplished in water in three steps. The range of substrates for d-tagatose-3-epimerase (DTE) is extended to 1- and 6-deoxyketoses. An authentic sample of 6-deoxy-d-psicose is prepared from d-psicose. © 2009 Elsevier Ltd. All rights reserved.

Microbial oxidation of 2-C-methyl-d-ribitol and 2-C-methyl-d-arabinitol by Gluconobacter thailandicus NBRC 3254 produces 4-C-methyl-l-ribulose and 4-C-methyl-d-ribulose, respectively. Further, 4-C-methyl-l-ribulose and 4-C-methyl-d-ribulose were equilibrated by d-tagatose-3-epimerase (DTE) with 4-C-methyl-l-xylulose and 4-C-methyl-d-xylulose, respectively. These transformations demonstrate that polyol dehydrogenase and DTE act on branched synthetic sugars. The green preparation of all of the stereoisomers of 4-C-methyl pentuloses illustrates the ability of biotechnology to generate novel branched monosaccharides. © 2008 Elsevier Ltd. All rights reserved.

D-psicose, a new alternative sweetener, was produced from allitol by microbial oxidation of the newly isolated strain Enterobacter aerogenes IK7. Cells grown in tryptic soy broth medium (TSB) supplemented with D-mannitol at 37 degrees C were found to have the best oxidation potential. The cells, owing to broad substrate specificity, oxidized various polyols (tetritol, pentitol, and hexitol) to corresponding rare ketoses. By a resting cell reaction, 10% of allitol was completely transformed to the product D-psicose, which thus becomes economically feasible for the mass production of D-psicose. Finally, the product was crystallized and confirmed to be D-psicose by analytical methods.

l -Tagatose was produced directly from l -psicose by subjecting the same biomass suspension to microbial reduction followed by oxidation using a newly isolated bacteria Enterobacter aerogenes 230S. After various optimizations, it was observed that cells grown on xylitol have the best conversion potential. Moreover, E. aerogenes 230S converted l -psicose to l -tagatose at a faster rate in the presence of polyols such as glycerol, d -sorbitol, ribitol, l -arabitol, d -mannitol and xylitol. At 5% substrate concentration, the conversion ratio of l -psicose to l -tagatose was above 60% in the presence of glycerol. Identity of crystalline l -tagatose was confirmed by HPLC analysis, 13 C-NMR spectra, and optical rotation.

Although 6-azido-6-de-oxy-l-galactose in aqueous solution is in equilibrium between the open-chain, furan-ose and pyran-ose forms, it crystallizes solely as 6-azido-6-de-oxy-α-l-galactopyran-ose monohydrate, C(6)H(11)N(3)O(5)·H(2)O, with the six-membered ring adopting a chair conformation. The structure exists as hydrogen-bonded chains, with each mol-ecule acting as a donor and acceptor of five hydrogen bonds. There are no unusual crystal packing features and the absolute configuration was determined from the use of 1-azido-1-de-oxy-d-galactitol as the starting material.

University College of Pharmaceutical Sciences, Kakatiya University, Warangal-506 009 Manuscript received 2 April 1982, accepted 12 November 1982 Nine different 3-aryl-2-(N',N'-substituted aminomethyl)-4(3H)-quinazolinones have been synthesized by condensing 3-aryl-2-chloromethy1-4(3H)-quinazolinones with different secondary bases. Similarly, seven different 3-aryl-2-(N4-arylsulphonamido­methyl)-4(3H)-quinazolinones have been obtained on reacting 3-aryl-2-chloromethy1-4- (3H)-quinazolinones with various aryl sulphonamides. Thise compounds have been characterised by their analytical and spectral data. The antibacterial and antifungal activities of the compounds have been determined and the results are discussed.