摘要:

AbstractAmong the many molecular rearrangements that may occur in compounds with strained rings, valence (or valence bond) isomerizations have recently received special attention. Relief of strain in energy‐rich small or medium‐sized rings is the driving force behind these predominantly thermal (pyrolysis) reactions. In many instances, valence isomerizations must be considered as multicenter rearrangements (with six‐ or four‐membered cyclic transition states). This mechanism can be regarded as firmly established for Cope rearrangements, as well as for intracyclic diene syntheses and diene cleavages of strained rings, with which this pape

ISSN:0570-0833    

DOI:10.1002/anie.196300011

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

摘要:

AbstractRecent interest in the stereochemistry of displacement reactions involving second row elements has led to rapid advances in the preparation and resolution of asymmetric phosphorus compounds. The changes in optical activity accompanying substitution at an optically active phosphorus atom, the reactivity of cyclic phosphates, and the mechanism of intramolecular decomposition reactions involving a phosphorus centre are discussed in terms of the electronic structure of possible transition states.

ISSN:0570-0833    

DOI:10.1002/anie.196300111

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

摘要:

AbstractCompounds and dyes containing vinylsulfonyl groups or groupings which readily yield vinylsulfonyl groups possess a marked ability to add onto many compounds containing active hydrogen under alkaline conditions. They also react with natural substances of high molecular weight, e.g. wool and cellulose, which contain amino‐ or hydroxyl groups. These reactions lead to the formation of strong covalent bonds between the reactants. As a result of this finding, reactive dyes for nitrogenous and cellulose fibers have been develope

ISSN:0570-0833    

DOI:10.1002/anie.196300201

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

摘要:

AbstractAmong the derivatives of 3‐aminoquinazol‐4‐one and 3‐aminobenzotriazin‐4‐one are compounds with narcotic, sedative, analgetic, and muscle‐relaxant properties. Of special interest are compounds with one or several urethane groups and those substituted in the 3‐position by a mo

ISSN:0570-0833    

DOI:10.1002/anie.196300241

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

摘要:

AbstractDyes which contain only thiosulfate residues as water‐solubilizing groups are readily polycondensed on cellulose under mild conditions in the presence of condensing agents such as sodium sulfide to give insoluble, high molecular‐weight dyes. This type of fixation leads to wash‐fast dyeings and, in contrast to reactive dyes, involves no reaction with the fiber. The preparation and application of the dyes are desc

ISSN:0570-0833    

DOI:10.1002/anie.196300301

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

摘要:

AbstractA two‐component organometallic catalyst of composition CH3TiCl3·CH3AlCl2effects high‐speed polymerization of ethylene in the presence of chlorinated hydrocarbons at low temperatures. The catalyst does not undergo any alteration in the process. In contrast to the Ziegler catalysts, the titanium remains quadrivalent. Olefins of low‐molecular‐weight and with branched structures are produced. It proved possible to isolate the primary products of the polymerization at −50 to −100°C and to elucidate the mode of their formation from a knowledge of their structures. The findings are incompatible with either a cationic or anionic reaction mechanism. A novel type of mechanism is proposed, whereby the catalyst is supposed to have an ionic structure and molecular growth proceeds via π‐complex formation of the olefin with the titanium cation. The formation of ethylene/olefin copolymers i

ISSN:0570-0833    

DOI:10.1002/anie.196300321

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196300422

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196300433

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196300443

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196300453

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY