摘要:

AbstractCoroglaucigenin, which is known to be a 3β, 14β, 19‐trihydroxy‐5α‐card‐20: 22‐enolid, was transformed into 2α, 3β, 19‐triacetoxy‐14β‐hydroxy‐5α‐card‐20 : 22‐enolid. The latter was identical with the known tri‐O‐acetyl‐19‐dihydro‐calotropagenin. The structure of calotropagenin (1) is thu

ISSN:0018-019X    

DOI:10.1002/hlca.19700530122

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

AbstractA new method for the preparation of acetylenes by reating α‐halogeno‐ or α‐sulfonyloxyketones with p‐toluenesulfonylhydrazine is

ISSN:0018-019X    

DOI:10.1002/hlca.19700530123

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

Abstractcis, cis‐, cis, trans‐ andtrans, trans‐o‐Dipropenylbenzene (cis, cis‐, cis, trans‐ andtrans, trans‐1) were prepared. At 225°cis, cis‐1isomerises to givecis, trans‐1and vice versa. The isomerisation follows 1. order kinetics. At equilibrium 89%cis, trans‐ and 11%cis, cis‐1are present. It is shown by deuterium labelling that the isomerisation is due to aromatic [1, 7a] sigmatropic H‐shifts.trans, trans‐1rearranges at 225° to yield 2, 3‐dimethyl‐1, 2‐dihydronaphthalene (3). This can be visualized by disrotatory ring closure oftrans, trans‐1followed by an aromatic [1, 5s] H‐shift. Whencis, cis‐ orcis, trans‐1are heated for 153 hrs at 225° a small amount (3%) of 1

ISSN:0018-019X    

DOI:10.1002/hlca.19700530124

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

AbstractUnivalent copper is stabilized in aqueous medium by the non‐protophilic ligand CH3CN, allowing ligand displacement reactions to be investigated as if a stable CuI‐hydrate did exist. Under these conditions the formation of CuI‐complexes with imidazole and its derivatives has been studied in polar solution in the absence of CuII. Imidazole (ImH) acts upon CuIas a bidentate ligand forming polynuclear chains according to the equationHistamine reacts in the same way,i. e.the coordination number of CuIdoes not exceed 2; by comparison of the complexes of CuIwith histamine and its N‐methyl‐derivatives it is shown that no six‐membered chelate – which sterically would be possible – is built up. Trigonal as well as tetrahedral coordination of CuI–i. e.chelate formation – in dilute polar solutions are confined to π‐ ord‐acceptor ligands,e. g.bipyridine or methionine. Conclusions are drawn from this on the requirements for redox

ISSN:0018-019X    

DOI:10.1002/hlca.19700530125

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

AbstractUsing a new mathematical treatment, the nature and stability constants of the simple and mixed complex‐species of copper(II) with hydroxyde and ammonia as ligands have been determined. The solubility curves of CuO in heterogeneous equilibrium have been identified in function of pH only and in function of pH and pNH3totat 25° and unit ionic strength (NaClO4).The predominent species in the relatively dilute system limited by the ionic strength are [Cu2+], [Cu(OH)2], [Cu(OH) 3−], [Cu(OH) 42−], [Cu(NH3) 22+], [Cu(NH3) 32+], [Cu(NH3) 42+], [Cu(NH3) (OH)+], [Cu(NH3)3(OH)+] and

ISSN:0018-019X    

DOI:10.1002/hlca.19700530126

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

ISSN:0018-019X    

DOI:10.1002/hlca.19700530127

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

ISSN:0018-019X    

DOI:10.1002/hlca.19700530101

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY