摘要:

AbstractBranched‐chain sugars have recently been isolated in larger numbers from microorganisms and higher plants as glycoside components of antibiotics or phenolic compounds. They also occur in plants in cell wall polysaccharides. Sugars with methyl, hydroxymethyl,formyl, hydroxyethyl, and glycoloyl branches have so far been found in nature. Many new methods have been developed for the synthesis of these sugars. With one exception, the branched sugars known at present can be divided biogenetically into three groups. Sugars with methyl branches are formed by C1transfer, sugars with hydroxyethyl branches by C2transfer to a hexose chain, and sugars with hydroxymethyl or formyl branches by rearrangement of a hexose or pentose chai

ISSN:0570-0833    

DOI:10.1002/anie.197201591

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractThe reaction of two solid phases X and Y to give a solid compound XYvis taken as an example for the discussion of transport mechanisms and reaction steps. The following methods of investigation are discussed: determination of the rate law, marker experiments, and calculation of the reaction rate. It is pointed out that the investigation of powder reactions leads to problematic conclusions.

ISSN:0570-0833    

DOI:10.1002/anie.197201731

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractIn this progress report, the properties and behavior of the positron (“positive electron”, anti‐electron) and of the positronium, a “hydrogen atom” containing a positron instead of a proton, are considered from the chemist's viewpoint. Examples are given to demonstrate the development of positronium chemistry, in aqueous solution and in the gaseous, liquid, and solid phases, with its problems and poss

ISSN:0570-0833    

DOI:10.1002/anie.197201791

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractEarlier evidence led to the view that in bimolecular olefin‐forming eliminations the anti steric course is generally preferred over the syn. Recent experiments, however, show that in some common bimolecular elimination reactions, notably those involving onium bases, syn‐ and anti‐eliminations proceed side by side, the former preferentially leading to the trans‐ and the latter to the cis

ISSN:0570-0833    

DOI:10.1002/anie.197202001

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197202151

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197202161

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197202171

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197202181

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197202201

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197202211

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY