摘要:

Michael‐Reaktionen von Pyridinium‐1‐alkylacetamidenDie leicht aus Methylpyridinium‐1‐acetat und primären Aminen zugänglichen Pyridinium‐1‐alkylacetamide5reagieren mit Chalconen und Natriummethylat in Ethanol in hohen Ausbeuten zu 3‐alkylaminocarbonylsubstituierten Tetrahydroindolizinen6. Diese unterliegen einer schnellen und kompletten Ringöffnung mit Essigsäure zu Pyridiniumsalzen8.Analoge Salze7erhält man direkt aus den Pyridinium‐1‐alkylacetamiden5durch Michael‐Addition an die Chalcone in Gegenwart von Dimethylamin als Katalysator.Um diese Michael‐Addukte zu den N‐Alkyl‐4, 6‐diaryl‐2‐pyridonen9zu cyclisieren, sind hohe Temperaturen erforderlich. Dabei werden niedrige Ausbeuten an diesen Produkten erzielt. Weiterhin entstehen die NH

ISSN:0021-8383    

DOI:10.1002/prac.19833250202

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

About the Nitration of Ethylene OxideNitration of ethylene oxide with pure nitric acid of different concentrations as well as in presence of sulphuric acid was carried out.The products, ethyleneglycol dinitrate1, diethylenglycol dinitrate2, triethyleneglycol dinitrate3, tetraethylenglycol dinitrate4, ethyleneglycol mononitrate5, diethyleneglycol mononitrate6, and 2, 2′‐dinitratediethylsulphate7were structurally determined by i. r.‐ and1H‐n. m. r.‐spe

ISSN:0021-8383    

DOI:10.1002/prac.19833250203

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

Azomethineimine. VI. On the Thermic Behaviour of the Photochromic System Azomethineimine/Diaziridine, Investigated by Means of the Photoproducts of Pyrazolidone‐(3)‐AzomethineiminesThe photochemically obtained cycloproducts2of pyrazolidone‐(3)‐azomethineimines1react thermically to1in aprotic solvents. This backreaction was investigated by following up the growth of the intensive long wave absorptionband of1. The kinetic analysis was carried out according to SWINBOURNE[5, 6]. The thermic backreaction is accelerated by factors favouring a polarization of the CN(2)‐bond (Cδ+ Nδ−) of diaziridine2. Such factors are polar solvents, donors in the substituent R and extensive, easily polarizable π‐electronic systems in R. The influence of substituents on the backreaction can be correlated by means of the σ+‐Hammett‐constants. For most compounds the values of EA≈ ΔH≠, Δ≠and ΔG≠were determined. The possible reaction mechanism is discussed. The influence of steric factors on the thermic backreaction is regarded as a first indication of an ex

ISSN:0021-8383    

DOI:10.1002/prac.19833250204

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

Azomethineimines. VII. Photochemical and Thermic Behaviour of Azarylsubstituted Pyrazolidone‐(3)‐AzomethineiminesIn principle the photochemical behaviour of azarylsubstituted pyrazolidone‐(3)‐azomethineimines1does not differ from other pyrazolidone‐(3)‐azomethineimines. Except for the acridyl‐(9)‐substituted compound in aprotic solvents they react to bicyclic diaziridines2. The quantum yield of this reaction has a value of nearly 0.3. For two of the diaziridines2the photochemical backreaction was realized. Results of the investigation of the thermic backreaction show the expected stability of the bicyclic diaziridines2a–d. All the investigated compounds have a pronounced tendency towards several irreversib

ISSN:0021-8383    

DOI:10.1002/prac.19833250205

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

The Coordinative Behaviour of N‐Substituted 2‐(Δ2‐Imidazolin‐2‐yl)‐phenols as Metal ExtractantsN‐Substituted 2‐(Δ2‐imidazolin‐2‐yl)‐phenols (R4NNOH) are obtained by the reaction of N‐alkyl diaminoethane‐1, 2 and 2‐hydroxybenzoic acid esters. In contrast to many other copper(II) complexes with the donor set N2O22−(A), the species Cu(R4NNO)2(B) are easily soluble in nonpolar solvents. The reason is the monomeric square‐planar structure ofB, which differs from the polymeric distorted octahedral structure ofA.The two maxima in the vis‐spectra of Cu(R4NNO)2and Ni(R4NNO)2are assigned to the 3 dxy → 3 dx2‐y2and the 3 dxz, 3 dyz → 3 dx2‐y2electron transitions. The shift of these maxima, which is connected with the dissolution in chloroform, is explained by the formation of hydrogen bonds between the solvent and the N‐alkylated nitrogen atoms of the ligands.1H‐n. m. r.‐spectra and solubility of the ligands and t

ISSN:0021-8383    

DOI:10.1002/prac.19833250206

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

Deactivation Behaviour of Arenes and Heteroarenes. XXXVI. The Solvent and Temperature Dependence of Deactivation Behaviour of 9, 9′‐Bis(acridizinium‐yl) at High ConcentrationAt room temperature the geometrical structure of the fluoresceing singlet state of 9, 9′‐bis(acridizinium‐yl) is determined by the solvent. In solvents of the type A (water, methanol, acetonitril) a plain S1‐state emits, in the case of the solvent type B (ethanol, propanol‐(2)) the S1‐state is twisted. Both excited states have different emission spectroscopical properties.At high concentration (c ≥ 10−4mol l−1) in the case of the solvent type B a new emission band is observed, and the monomer emission is quenched. This new band is interpreted as a fluorescence from a molecular associate in the excited state. The intensity of this associate band is increasing with decreasing temperature. It is shown that this band is the result of molecular association in the ground state. From the photochemical irradiation it follows that only in the case of the solvent type B a photocycloaddition is possible. The plain

ISSN:0021-8383    

DOI:10.1002/prac.19833250207

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

Reactions of o‐Lithio‐lithiumphenolate and o‐Lithio‐N‐methyl‐lithiumanilide with Halides of Phosphorus, Arsenic and SiliconThe title compounds and chlorides of the type CIERn (E = P, As, Si) react smoothly in a molecular ratio of 1:2 to give the corresponding disubstituted phenole and N‐methylaniline derivatives, respectively. Attempts with an 1:1 ratio show different results depending on the reactivity of the EO or EN species towards organ

ISSN:0021-8383    

DOI:10.1002/prac.19833250208

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

1H‐N. M. R.,13CN. M. R., and I. R.‐Investigations Concerning Tautomerism of15N‐Labeled 3‐Methyl‐1‐phenyl‐Δ2‐pyrazolin‐5‐oneThe behaviour of the15N‐mono and dilabeled compound in dependence on temperature and solvent polarity is described. Chemical shifts,nJ(15N1H), andnJ(15N13C) coupling constants (n = 1 – 3) have been determined. In the cases of 2, 2, 2‐trifluoroethanole and hexafluoroisopropanole the Δ4‐pyrazolin‐3‐one is stabilized and detected by3J(15N2H4) = 3 Hz,1J(13C315N2) = 11, 0 Hz and δ(13C5). In HMPT the 5‐hydroxypyrazole form predominates and is characterized by3J(15N1H4) = 5, 1 Hz and δ (13C5).Coupling constants3J(15N2H4) and J(13C315N2) could not be observed in this solvent.In accordance with1H‐ and13C‐n. m. r.‐parameters i. r. measurements in dependence on temperature lead to the conclusion that in DMSO and THF for instance all three tautomers are present and variation of temperature does not change the equilibrium between the tautomers.A good relationship between the content of the CH2, OH and NH f

ISSN:0021-8383    

DOI:10.1002/prac.19833250209

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

Theoretical Studies on the Electrophilic Attack. IX. Intramolecular H‐Shifts in the ortho‐Disubstituted Aromatic Compounds o‐Xylene and 1, 2‐DifluorobenzeneA potential energy characterization of the proton shifts in the above cited 1, 2‐disubstituted aromatic compounds and their dependence on solvent influence are studied by means of theoretical methods. The results complete in many points our knowledge of experimental data in solution estimated from n. m. r. spectroscopic inves

ISSN:0021-8383    

DOI:10.1002/prac.19833250210

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

The Influence of the Strain Energies on the Ionization and the Fragmentation of Tricyclo [5.2.1.02, 6]decanes, ‐decenes and ‐decadienesThe mass spectra of the title compounds are discussed. The inverse relationship of the abundance of the molecular ions with the calculated strain energies has been found to occur in the stereoisomers. The main fragmentation of the alkenes is the Retro‐Diels‐Alder cleavage. The stereochemical effects influence also the ionization and appearance

ISSN:0021-8383    

DOI:10.1002/prac.19833250211

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY