Nachrichten aus der ChemieVolume 50, Issue 6 p. 749-750 Bücher Wie aus einem Guß: Glycoscience: Chemistry and Chemical Biology I-III Hrsg. von Bertram Fraser-Reid, Kuniaki Tatsuta, Joachim Thiem. Springer, Heidelberg 2001. 2854 Seiten, geb. 700,- Euro. ISBN 3-540-67765-8 (mit CD-ROM 934,- Euro ISBN 3-540-67764-X) Peter Köll, Peter Köll OldenburgSearch for more papers by this author Peter Köll, Peter Köll OldenburgSearch for more papers by this author First published: 01 May 2010 https://doi.org/10.1002/nadc.20020500631AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume50, Issue6Juni 2002Pages 749-750 RelatedInformation

[1] As part of the European contribution to the Large-Scale Atmosphere-Biosphere Experiment in Amazonia (LBA-EUSTACH), aerosols were sampled at representative pasture and primary rainforest sites in Rondonia, Brazil, during the 1999 burning season and dry-to-wet season transition (September-October). Water-soluble organic compounds (WSOCs) within the samples were characterized using a combination of 1 H Nuclear Magnetic Resonance (NMR) spectroscopy for chemical functional group analysis, and Gas Chromatography-Mass Spectrometry (GC-MS) for identification and quantification of individual low-molecular-weight compounds. The 1 H NMR analysis indicates that WSOCs are predominantly aliphatic or oxygenated aliphatic compounds (alcohols, carboxylic acids, etc.), with a minor content of aromatic rings carrying carboxylic and phenolic groups. Levoglucosan (1,6-anhydro-β-D-glucose), a well-known cellulose combustion product, was the most abundant individual compound identified by GC-MS (0.04-6.90 μg m -3 ), accounting for 1-6% of the total carbon (TC) and 2-8% of the water-soluble organic carbon (WSOC). Other anhydrosugars, produced by hemicellulose breakdown, were detected in much smaller amounts, in addition to series of acids, hydroxyacids, oxoacids, and polyalcohols (altogether 2-5% of TC, 3-6% of WSOC). Most correlated well with organic carbon, black carbon, and potassium, indicating biomass burning to be the major source. A series of sugar alcohols (mannitol, arabitol, erythritol) and sugars (glucose, fructose, mannose, galactose, sucrose, trehalose) were identified as part of the natural background aerosol and are probably derived from airborne microbes and other biogenic material. The bulk of the WSOCs (86-91% WSOC) eluded analysis by GC-MS and may be predominantly high-molecular weight in nature.

Suitable carbohydrate-derived terminal olefins have been coupled by ring-closing metathesis reaction following a silicon tethering strategy, generating very long contiguous chains of carbon atoms each equipped with specific stereochemistry and functionality.

Two new chiral glyco-oxazolidin-2-one auxiliaries based on d-glucose are described. Some N-acyl derivatives were synthesized and used in dialkylboron-mediated asymmetric aldol reactions. All reactions delivered as the major diastereomer those predicted by the Zimmerman–Traxler model and were separated by column chromatography and mostly isolated in moderate to good yields.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The formation of W(VI) complexes of two C-6 epimeric heptitols, namely meso-D-glycero-D-gulo-heptitol and D-glycero-L-gulo-heptitol, has been studied in aqueous solution. In alkaline medium, both heptitols form two types of dinuclear complexes which have been structurally characterized from multinuclear NMR data. In the first type T, the site of chelation is a tridentate xylo system. In the second type P, the site of chelation is a pentadentate system with a central;xylo triol group. The influence of the nature and orientation of the substituents attached to the lateral carbon atoms of the chelating site upon the complex stability is discussed. (C) 1998 Elsevier Science Ltd. All rights reserved.

Chiral N-acylated oxazolidin-2-ones readily available from D-xylose have been demonstrated to undergo highly diastereoselective alkylation reactions via their lithium imide enolates to afford alpha-branched products. These are easily purified and hydrolyzed without difficulty allowing isolation of the desired ramified carboxylic acids in high enantiomeric excesses and to return the auxiliaries for reuse. (C) 1996 Elsevier Science Ltd

Two new chiral oxazolidin-2-ones have been easily prepared from D-xylose and studied as chiral derivatizing agents (CDA's) for the resolution of racemic carboxylic and sulfonic acids The resultant diastereomers are readily separated by chromatographic methods and easily hydrloyzed to isolate the resolved materials in high optical purities and to return the CDA's for reuse.

The molecular structures of the title compounds were determined by X-ray crystallography, using direct methods, and refined to final conventional residual parameters of R = 0.042, 0.035, 0.060, 0.062, and 0.047, respectively. meso-d-glycero-l-altro-Heptitol crystallised usually as a monohydrate from moist ethanol with single molecules occurring in the crystal as a racemate of chiral conformers adopting a planar zigzag conformation. Thus, a 1,3-parallel O-3/ /O-5 interaction is tolerated with a distance of 265.0 pm. By thorough exclusion of water, an unhydrated morph was obtained from ethanol and investigated at 173 K. The conformations of single molecules parallel those observed in the hydrate. The O-3–O-5 distance is 267.6 pm. Molecules of the derived heptaacetate avoid this interaction by bending to a sickle, but tolerate, instead, an O-3/ /C-6 relationship with a distance of 295.0 pm. Also, in this case, chiral conformers are observed, which are matched by their enantiomers in the unit cell. meso-d-glycero-l-ido-Heptitol is found in a doubly bent chiral conformation which is free of 1,3-parallel interactions and resembles that found in iditol hexaacetate, but not in iditol itself. Again, a racemate of conformers is observed in the unit cell. The molecules of the heptaacetate of chiral d-glycero-l-galacto-heptitol are found in a sickle conformation, free of 1,3-parallel interactions, a situation already observed for the parent alditol but which could not have been predicted from recent investigations of the solid state structures of other alditol acetates. The occurrence of 1,3-parallel O/ /O interactions in alditols and other acyclic carbohydrates is discussed comprehensively.

The structures of the 1,2,3,4,5,6-hexa-acetates derived from allitol, galactitol, d- and dl-mannitol (conglomerate and racemate), d- and dl-glucitol, and dl-altritol have been determined by X-ray crystallography, using direct methods, and comprise a complete set of solid-state structures. Compared with the parent alditols, the hexa-acetates have much greater freedom to adopt conformations which involve 1,3-parallel interactions of oxygen and carbon atoms. Such interactions of acetoxyl groups do not impose dominating steric constraints. Parallel alignment of the flat acetoxyl groups can result in the thermodynamically most favoured dense packing of molecules in the crystal.

Two so far unknown minor compounds 1, 6-anhydro-beta-D-altropyranose and 1, 6-anhydro-beta-D-allopyranose were isolated during the classic pyrolysis of cellulose in the presence of copper powder. Although for one of them a new intermediate must be proposed, their occurrence can be explained from already proven or postulated intermediates.

Treatment of pentoses and some hexoses with potassium cyanate in aqueous solutions, buffered with sodium dihydrogen phosphate or ammonium chloride, gave glycosylamine 1,2-(cyclic carbamates) {glycofurano(or pyrano)[1,2-d]oxazolidin-2-ones}. Most of the products had furanoid structures, but d-mannose and d-lyxose gave preponderantly pyranose derivatives. Epimerisation at C-2 was observed in certain reactions. The products and their acetylated derivatives were characterised by 1H- and 13C-n.m.r. spectroscopy.

Addition of Nitromethane to Aldoses. – A Comprehensive Study of the Diastereoselectivity of the Fischer‐Sowden Reaction by the Help of 13C‐NMR Spectroscopy1)The addition of nitromethane to aldoses, commonly referred to as „Fischer‐Sowden reaction”︁, is not as stereoselective as can be concluded from the literature. This is the outcome of a comprehensive study which covered besides glyceraldehyde all aldotetroses, ‐pentoses and ‐hexoses. The ratio of the pair of diastereomeric nitroalditols has been determined in each case by 13C‐NMR spectroscopy. Thus, incidentially, a whole set of spectral data for all tetritols, pentitols, hexitols and heptitols with a terminal nitro group has been obtained, which can be correlated systematically to the respective data for the parent alditols. From these results follows that at least under conditions which give high yields of products, the reaction is thermodynamically controlled; thus, the product ratio is determined by the different energy content of the product nitroalditols (or their nitronates), which is a result of different patterns of steric interactions between substituents.

The crystal structures of four nitroheptitols obtained fromd-galactose andd-glucose by a Fischer-Sowden reaction,i.e., 7-deoxy-7-nitro-l-glycero-l-galacto-heptitol monohydrate, 7-deoxy-7-nitro-d-glycero-l-galacto-heptitol, 7-deoxy-7-nitro-d-glycero-l-gulo-heptitol, and 1-deoxy-1-nitro-d-glycero-d-gulo-heptitol, were determined by X-ray diffraction using direct methods. Thel-glycero-l-galacto and thed-glycero-l-gulo isomers adopt the expected conformations, one having the extended planar zig-zag geometry and the other being bent to a sickle. Remarkably, the other two compounds havingd-glycero-l-galacto andd-glycero-d-gulo configurations showed extended planar conformations, both of them thus tolerating a parallel 1,3-interaction between oxygens (O//O). In all compounds, the oxygen atoms of the nitro group show a preference in their orientations to the hydrogen atoms at C-1 and C-2, one found in a position synclinal to H-12 and the other 1,3-synclinal to H-2.

The diazo-α,α′-diketo-aldonic acid 3 is prepared from the 1-deoxy-1-diazo-fructose 1 by condensation with methyl oxalyl chloride in 61 % yield. The title compound 3 is very labile towards base but is moderately stable towards acid. These properties are contrary to those observed for normal diazoalkanes.

Die Kristallstrukturen von vier freien und drei acetylierten 2,6-Anhydro-1-desoxy-1-nitroalditolen, nämlich von 2,6-Anhydro-1-desoxy-1-nitro- d - glycero - d - gulo -heptitol, 2,6-Anhydro-1-desoxy-1-nitro- d - glycero - l - manno -heptitol, 3,4,5,7-Tetra- O -acetyl-2,6-Anhydro-1-desoxy-1-nitro- d - glycero - l - manno -heptitol, 2,6-Anhydro-1-desoxy-1-nitro- l - manno -hexitol, 3,4,5-Tri- O -acetyl-2,6-Anhydro-1-desoxy-1-nitro- l - manno -hexitol, 2,6-Anhydro-1-desoxy-1-nitro- d - galacto -hexitol und 3,4,5-Tri- O -acetyl-2,6-Anhydro-1-desoxy-1-nitro- d - altro -hexitol wurden durch Röntgenstrukturanalyse unter Verwendung direkter Methoden bestimmt. In allen Verbindungen findet sich die Nitromethylgruppe in antiperiplanarer Anordnung zu C-3 mit resultierender gauche -Anordnung zum Ringsauerstoffatom. Die Sauerstoffatome der Nitrogruppe bevorzugen Lagen, bei denen sich eines dieser Atome in synclinaler Position zu H-12 und das andere in entsprechender synclinaler 1,3-Position zu H-2 befindet.

AbstractDie aus D‐Ribose, D‐Xylose und D‐Galactose durch Nitromethanaddition und nachfolgende Cyclodehydratisierung erhältlichen 2,5‐Anhydro‐1‐desoxy‐1‐nitrohexitole und ‐heptitole 1, 4, 7 und 10 sind geeignete Edukte, die sich nach Acetylierung und Reduktion mittels PCl3 in Pyridin zu den Glycofuranosylcyaniden 3, 6, 9 und 12 umsetzen lassen. Da hierbei keine Anomerisierungen beobachtet werden und eine Nachbargruppenbeteiligung vicinaler Acetoxysubstituenten nicht erfolgen kann, lassen sich auf diese Weise selbst 1,2‐cis‐Cyanide wie 3 und 9 darstellen, was mit üblichen Methoden kaum gelingt. Die Strukturen beschriebener Verbindungen wurden durch Röntgenstrukturanalyse der Nitroverbindungen 1, 4 und 7 sowie des Cyanids 12 gesichert bzw. indirekt gestützt.