摘要:

AbstractCriteria for the mechanism of 1,3‐dipolar cycloadditions which lead to 5‐membered rings are provided by the stereoselectivity observed with cis‐trans isomeric dipolarophiles, by the effect of solvent and substituents on the rate constants, by the activation parameters, and by orientation phenomena. A concerted addition, which can also be described in terms of molecular orbitals and in which the two new σ‐bonds are formed simultaneously, although not necessarily at equal rates, offers the best explanation of the experiment

ISSN:0570-0833    

DOI:10.1002/anie.196306331

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

摘要:

AbstractWhile silicon and sulfur, which are situated to the left and to the right of phosphorus in the periodic table, from numerous chain and cyclic Si–Si and S–S‐compounds with varying numbers of members, until recently the polyphosphance chemistry has been limited to the two‐membered compounds diphosphane P2H4and its derivatives. A number of results obtained in studies on polyphosphanes carried out in recent years will therefore be discussed, which, together with some more recent work by other authors, have led to an expansion of our knowledge of the prepration and properties of straight and branched‐chain as well as of cyclic and polycylic –

ISSN:0570-0833    

DOI:10.1002/anie.196306461

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

摘要:

AbstractIn the last account of our investigations in the amide field [1], we reported inter alia on the preparation and reactions of trisformamidomethane. Further work with this compound led to simple syntheses particularly of heterocyclic compaunds. Following the pattern of these syntheses, compounds other than trisformamidomethane were employed for formylation and ring‐closure; these included formates, orthoformates, formamidine, dimethylformamide diethylacetal, and formamide. Part of this recent research is reported belo

ISSN:0570-0833    

DOI:10.1002/anie.196306551

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

摘要:

AbstractIn this article, the gradations in reactivity of organic oxygen, sulfur, and selenium compounds of equivalent structure (“isologues”) are reviewed. New or improved methods for the preparation of organoselenium compounds (especially saturated and unsaturated selenides) are described. The addtion of selenols onto acetylenic triple bonds cheifly to cisaddu

ISSN:0570-0833    

DOI:10.1002/anie.196306601

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

摘要:

AbstractN‐(4‐Chlorophenyl)‐N′‐methoxy‐N′‐methylurea (Aresin®)‐ and N‐(3,4‐dichlorophenyl)‐ N′‐ methoxy‐N′ ‐methylurea (Afalon®) are two new herbicides with characteristic selective activity. A simple and convenient method

ISSN:0570-0833    

DOI:10.1002/anie.196306701

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

摘要:

AbstractThioether groups participate in nucleophilic substitution reactions at adjacent carbon atoms, in the addition of alkane and arenesulfenyl halides onto olefinic double bonds, and in elimination reactions which lead to olefins and which proceed via intermediate episulfonium ions. Studies of alkylthioacrylic acid derivatives, which are readily synthetized because of the neighboring group effect, show that the presence of thioether groups in the α‐position of acrylic acid systems leads to particularly high reactivity in “head‐to‐head” dim

ISSN:0570-0833    

DOI:10.1002/anie.196306741

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196306831

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196306842

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196306852

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196306863

出版商:Hüthig&Wepf Verlag    

年代:1963

数据来源: WILEY