摘要:

AbstractNitrosobenzene (NB) and nitroso‐tetr‐butane (NtB) were used to trap the photogenerated rhenium pentacarbonyl radical. Self trapped radicals and spin adducts were studied in detail by EPR spectroscopy. In methylene chloride, both nitroxide and anilino spin adducts can be observed with NtB at −30°. In contrast, only the nitroxide spin adduct of nitrosobenzene was observed in either hexane, or methylene chloride solution. This solvent controlled spin adduct chemistry, can be explained in terms of the solute‐solvent int

ISSN:0009-4536    

DOI:10.1002/jccs.198400045

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractThe chemical state of particles of 5wt% Fe in α‐Fe2O3and the subsequently reduced iron particles supported on different particle size (50–200mesh) of silica (SiO2), alumina (Al2O3), magnesium oxide (MgO) and carbon (C) was examined by Mössbauer spectroscopy at various stages of calcination and reduction. The particle size of the α‐Fe2O3supported on different mesh sizes (50, 100, 140, 200mesh) of SiO2has been determined. The strength of metal‐support interaction with respect to the kind of support was found to be MgO>Si

ISSN:0009-4536    

DOI:10.1002/jccs.198400046

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractThe effect of the addition of a second metals such as Zn and Ni on the calcinaton and reduction of alumina, magnesia and silicasupported iron catalysis with total iron loading of 5wt% is investigated by Mössbauer spectroscopy. It is shown that the reducibility of supported α‐Fe2O3is gradually increased by adding the second metal. The values of the magnetic hyperfine field obtained from Mössbauer spectra for the Zn or Ni‐added α‐Fe2O3or Fe catalysts decreased with increasing second meta

ISSN:0009-4536    

DOI:10.1002/jccs.198400047

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractA spectrophotometric method has been used for the determination of the dissociation constant ofP‐nitroaniline indicator (which has a charge type A+B0) in various THF‐water solvent mixtures at 25°C. The dissociation constant is found to decrease with the addition of THF which indicates that the basicity of the medium is increased by the addition of the organic solvent.The relative basicity of the medium is compared with other aqueous‐organic solvent mixtures and the trend of decreasing basicity is in the order THF‐H2O>DMF‐H2O>AN

ISSN:0009-4536    

DOI:10.1002/jccs.198400048

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractFormation of a series of Schiff bases derived fromp‐aminosalicylic acid I and various aromatic aldehydes has been studied kinetically in ethanol medium in presence of piperidine as a basic catalyst. The order of the reaction is determined to each reactant by following the concentration of the Schiff base formed during the reaction. The reaction is Kinetically third‐order in the presence of low concentration of piperidine, first‐order to each ofI, aldehyde and piperidine. On the other hand, in presence of ≥5×10−4Mof piperidine the order of the reaction changed to second‐order, thus much the reaction is independent of piperidine concentration. The rate determining step is suggested to be the dehydration of the carbinolamine intermediate step 4. Variation in reaction rate constants with the different substituent of the aromatic aldehyde, with substituents of aromatic amine and with the nature of the hydroxylic organic solvents as reaction medium are studied a

ISSN:0009-4536    

DOI:10.1002/jccs.198400049

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractA simple and effective preparation of enamines from bulky ketones and secondary amines has been achieved with the aid of Lewis acid on various solid supports. The optimized yields were higher than those obtained without the solid support. Factors affecting the yield and regioselectivity of these reactions were also studied. Evidence showed that the reaction proceeded simultaneously in solution and on the solid support.

ISSN:0009-4536    

DOI:10.1002/jccs.198400050

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

Abstract(E)‐1‐Alkanesulfonylpropenes and (E)‐1‐Alkanesulfinylpropenes have been synthesized in good to excellent yields. Studies correlating molecular structure and fragmentation patterns upon electron impact have been carried out. Double hydrogen rearrangements with the elimination of alkenyl radicals are the most facile fragmentations for (E)‐1‐alkanesulfonylpropenes. Single hydrogen rearrangement with alkene elemination is however the most important fragmentation for (E)‐1‐alkanesulfinylpropenes. In this case the hydrogen atom only migrates to the sulfinyl oxygen. These differences in fragmentation patterns between the (E)‐styryl‐alkyl‐sulfones/sulfoxides and the (E)‐propenyl‐alkyl‐sulfones/sulfoxides are attributed to the fact that different io

ISSN:0009-4536    

DOI:10.1002/jccs.198400051

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractThe Friedel‐Crafts reaction of 1‐azaazulan‐2‐ones with α‐haloacid chloride in the presence of aluminum trichloride gives the corresponding α‐haloacyl derivatives. Treatment of these reaction products first with various secondary amines and then with sodium borohydride gives new adrenergic active amin

ISSN:0009-4536    

DOI:10.1002/jccs.198400052

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractThe preparation of some 3,5‐diarylidene‐1‐thipyran‐4‐one derivatives (Ia‐e) was described. Oxidation of Ia, b and Ie with hydrogen peroxide gave the corresponding dioxides (IIa‐c). Reaction of the 1‐thiapyran‐4‐one derivatives with bromine, Grignard reagents, and amines were studied. Structural assignments are supported by spectral (UV,

ISSN:0009-4536    

DOI:10.1002/jccs.198400053

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractChalcone and 4‐methoxychalcone react with chlorosulfonic acid to give chalcone‐p‐sulfonyl chloride and 4‐methoxchalcone‐3‐sulfonyl chloride respectively. The sulfonyl chlorides were converted into 13 sulfonyl derivatives by reaction with nucleophiles. With hydrazine and phenylhydrazine the chalconesulfonyl chlorides were cyclised to the corresponding hydrazinopyrazolines. In contrast, with N,N‐dimethyl‐hydrazine only the dimethylsulfonohydmides were obtained, and no attack on the carbonyl group was observed. Possible reasons for this difference in behaviour are discussed, together with spectroscopic evidence for the stru

ISSN:0009-4536    

DOI:10.1002/jccs.198400054

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY