ISSN:0570-0833    

DOI:10.1002/anie.199505051

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe chemistry of covalent inorganic azides originated with the synthesis of aqueous HN3solutions by Tony Curtis in 1890. A little later, in 1900, it proved possible to prepare iodine azide, IN3, as the first member of the meanwhile complete series of halogen azides. Since then it has been possible to synthesize, in addition to HN3and the stable salt H2N 3+SbF 6−, azide compounds of elements from Groups 13 to 17. In these compounds the N3moiety acts as a pseudohalogen and is primarily covalently coordinated to the nonmetal. Only a few organic azides, however, as well as HN3, H2N 3+, and all halogen azides have been thoroughly studied with respect to structure and bonding. The combined application of diffraction methods (X‐ray and electron diffraction) and microwave spectroscopy together with quantum chemical approaches such as ab initio SCF and density functional calculations have led in the last few years to an improved understanding of the molecular properties of numerous nonmetal azides, almost all of which are explosive. This interaction of theory and experiment has greatly enhanced the development of azide chemistry and has led to realistic expectations for the synthesis of as yet unknown nonmet

ISSN:0570-0833    

DOI:10.1002/anie.199505111

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractRecognition of carbohydrates by proteins and nucleic acids is highly specific, but the dissociation constants are relatively high (generally in the mMto high μMrange) because of the lack of hydrophobic groups in the carbohydrates. The high specificity of this weak binding often comes from many hydrogen bonds and the coordination of metal ions as bridge between sugars and receptors. Though weak hydrophobic interactions between sugars and proteins have also been identified, the unique shape of a complex carbohydrate under the influence of anomeric andexoanomeric effects (the glycosidic torsion angles are therefore often not flexible but are typically somewhat restricted) and the topographic orientation of the hydroxyl and charged groups contribute most significantly to the recognition process. Studies on the structure–function relationship of a complex carbohydrate therefore require deliberate manipulation of its shape and functional groups, and synthesis of oligosaccharide analogs from modified monosaccharides is often useful to address the problem. The availability of various monosaccharides and their analogs for the synthesis of complex carbohydrates together with the information resulting from structural studies (such a NMR or X‐ray studies on sugar–protein complexes) will certainly provide a basic understanding of complex carbohydrate recognition. An ultimate goal is to develop simple and easy‐to‐make non‐carbohydrate molecules that resemble the active structure involved in carbohydrate–receptor interaction or the transition‐state of an enzyme‐catalyzed transformation (for example, glycosidase or glycosyltransferase reactions) and have the approprite bioavailability to be used to control the carbohydrate function in a specific manner. In part one of this review we described various enzymatic approaches to the synthesis of monosaccharides, analogs, and related structures. We describe in this part enzymatic and chemoenzymatic approaches to the synthesis of oligosaccarides and analogs, including those involved in E‐selectin recognition, and strategies to inhibit glycosidases and

ISSN:0570-0833    

DOI:10.1002/anie.199505211

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199505471

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199505491

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199505531

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199505551

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199505571

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199505601

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199505631

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY