摘要:

AbstractOn treatment of 5‐bromo‐3‐methyl‐1‐phenylpyrazole, 2‐bromobenzo[b]thiophene and 2‐bromobenzo[b]thiophene‐1,1‐dioxide with potassium amide in liquid ammonia bromine migration to the adjacent carbon atom was observed. Considerable evidence for the occurrence of an intermolecular transbromina

ISSN:0165-0513    

DOI:10.1002/recl.19730920302

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractIn the homogeneous molybdenum‐catalysed epoxidation of olefins bytert‐alkyl hydroperoxides two competing processes, epoxidation and hydroperoxide decomposition, have been delineated.Hydroperoxide decomposition involves free‐radical reactions initiated by electron‐transfer reactions of Mo(V) and Mo(VI) complexes with the hydroperoxide. The rates and products of hydroperoxide decomposition are dependent on the solvent and the presence or absence of an olefin.The rate of epoxidation depends on the structure of the olefin and, after an initial period during which the rate changes, it becomes independent of the structure of the molybdenum compound originally added as the catalyst. The active catalyst in the epoxidation reaction is a molybdenum(VI) compound. The active epoxidizing agent is most likely a complex of molybdenum(VI) with the hydroperoxide, which transfers an oxygen atom to the olefin via a cyclic transition state analogous to that for the epoxidation of olefins with organic p

ISSN:0165-0513    

DOI:10.1002/recl.19730920303

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19730920304

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19730920305

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19730920306

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractThe synthesis, isolation and characterization of the stable complex [NiCl2(t‐C4H9NC)(C2H5OH)] is described. Spectral and magnetic data are provide

ISSN:0165-0513    

DOI:10.1002/recl.19730920307

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractTriphenylphosphonium dibromide converts endoxides into aromatic compounds in good yields. Endoxides having a configuration in which the oxygen atom is shielded from attack by agents normally used for this conversion react under mild conditions. A possible mechanism, involving induced SN1 cleavage of the carbon‐oxygen bond in the endoxides is give

ISSN:0165-0513    

DOI:10.1002/recl.19730920308

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

Abstract27Trans‐alkenoic, 2trans‐alkenemonoynoic and 2trans‐alkenepolyynoic acids with the first triple bond in the 5‐position could be obtained in high yield by coupling 1‐alkyl‐ and 1‐mono‐ or ‐poly‐ynylmagnesium bromides with 4‐bromocrotonic acid in tetrahydrofuran at low temperature.By hydrogenation in the presence of Lindlar's catalyst,cispolyenoic acids with a 2transdouble bond have been synthesized. On continued hydrogenation, the 2transdouble bond can be removed selectively. This new method has been applied to the synthesis of 2trans,5cis,8cis,11cis,14cis‐eicosapentaenoic acid and its hydrogenation to 5cis,8cis,11cis,14cis‐eicosatetraenoi

ISSN:0165-0513    

DOI:10.1002/recl.19730920309

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractAminations of 2,3‐, 2,4‐ and 3,4‐dibromoquinoline with potassium amide in different media have been investigated. Reactions of various types (bromine migration, dimerization, cine‐substitutions and various ring transformations) were found to occur.Mechanisms for the conversions observed are p

ISSN:0165-0513    

DOI:10.1002/recl.19730920310

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractThe mechanism of the conversion of chloropyrazine into 2‐cyanoimidazole by the action of potassium amide in liquid ammonia has been investigated. Using 2‐chloro[4′15N]pyrazine and 2‐chloro[2′14C]pyrazine it has been shown that ring contraction occurs by a nucleophilic attack of the amide ion at C(3), followed by fission of the C(3)

ISSN:0165-0513    

DOI:10.1002/recl.19730920311

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY