Sterische Hinderung bei stark polaren 2,6‐disubstituierten Azobenzolen

Hoyer, Ernst; Schickfluss, Rudolf; Steckelberg, Willi

doi:10.1002/ange.19730852209

Cited by 14 publications

(1 citation statement)

References 6 publications

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“…The hypsochromic shift of the maxima in going from 1 to 2 to 3 is attributed to steric crowding which leads to some loss of coplanarity and conjugation. A similar phenomenon has recently been observed when a proton was substituted by chlorine in the position artha to the azo group [21]. The dediazoniation of the compound under study in each of the solvents was stopped by azo coupling with 2-naphthol after the time necessary for ca.…”

Section: Ar-nensupporting

confidence: 67%

Dediazoniation of Arenediazonium Ions. Part XXII. Reactions of 2, 6‐Dialkyl‐Substituted Benzenediazonium Ions in Super Acids, Acetonitrile and Acetone

Laali¹,

Szele²,

Zollinger³

1983

Helvetica Chimica Acta

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Reactions of 2,4,6-trimethylbenzenediazonium (l), 2,6-diethylbenzenediazonium (2) and 2,6-diisopropylbenzenediazonium (3) tetrafluoroborates were studied in magic acid, SbF,/SO,ClF, acetonitrile and acetone by 'H-NMR and by analysis of the dediazoniation products. The N,-Np rearrangement of P-Nl5labelled tetrafluoroborates 1-3 was followed by I5N-NMR of the corresponding arylazonaphthols, as well as by MS analysis of the anilines obtained by reduction of the azo compounds. Diazonium salts 2 and 3 were synthesized for the first time and the steric effect of substituents at C (2) and C (6) on the reactions under study is discussed. All the results obtained can be rationalized by heterolytic dediazoniation of diazonium salts 1-3 and product formation from the corresponding aryl cations.

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Section: Ar-nensupporting

confidence: 67%

Dediazoniation of Arenediazonium Ions. Part XXII. Reactions of 2, 6‐Dialkyl‐Substituted Benzenediazonium Ions in Super Acids, Acetonitrile and Acetone

Laali¹,

Szele²,

Zollinger³

1983

Helvetica Chimica Acta

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ChemInform Abstract: STERISCHE HINDERUNG BEI STARK POLAREN 2,6‐DISUBSTITUIERTEN AZOBENZOLEN

Hoyer¹,

Schickfluss²,

Steckelberg³

1974

Chemischer Informationsdienst

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Influence of the Z/E configuration on the ¹³C¹⁵N coupling conditions ¹J(¹³C¹⁵N) in aromatic azo and diazo compounds

Fanghänel¹,

Radeglia²

1983

Org. Magn. Reson.

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The "C NMR spectra of singly 'SN-labelled Z/E isomers of azo and diazo compounds were recorded. The J( C N) coupling constants are strongly dependent on the geometrical configuration of the azo group, the relative position of the lone pair of electrons at the non-coupling azo nitrogen atom having a decisive influence. l3 15 INTRODUcIlONLittle experimental material is available in the literature on the influence of the geometrical configuration around an N=N double bond on the 'sN-'3C coupling conditions over one bond (see Fig. 1).Schwotzer et al.' found a relatively large difference between the 'J(13C1'N) values of the Z and E isomers in azoxybenzenes, whereas this difference is not very distinct in Z/E isomers of azimines. Recently, coupling constants of the ZIE isomeric azobenzenes and benzo[c]cinnoline were published,2 which also prove the specific influence of the configuration on the coupling conditions. Our own investigations show, however, that the assignments reported in Ref. In a previous study,3 we were also able to show that the I3C--l5N coupling constants of Z / E isomeric benzthiazoline-2-ylidenearyltriazenes and triazenium salts are significantly dependent on the geometrical configuration. To improve the understanding of this dependence, we have carried out a comparative study of the l3C-I5N coupling constants over one bond in Z -and E-azobenzenes 1, benzo[c]cinnoline (Z), diazocyanides 3, triazenes 4, and triazenium salts 5 with Z and E configurations, also including the literature values of azoxybenzenes 6.'

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Sterische Hinderung bei stark polaren 2,6‐disubstituierten Azobenzolen

Cited by 14 publications

References 6 publications

Dediazoniation of Arenediazonium Ions. Part XXII. Reactions of 2, 6‐Dialkyl‐Substituted Benzenediazonium Ions in Super Acids, Acetonitrile and Acetone

Dediazoniation of Arenediazonium Ions. Part XXII. Reactions of 2, 6‐Dialkyl‐Substituted Benzenediazonium Ions in Super Acids, Acetonitrile and Acetone

ChemInform Abstract: STERISCHE HINDERUNG BEI STARK POLAREN 2,6‐DISUBSTITUIERTEN AZOBENZOLEN

Influence of the Z/E configuration on the ¹³C¹⁵N coupling conditions ¹J(¹³C¹⁵N) in aromatic azo and diazo compounds

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Sterische Hinderung bei stark polaren 2,6‐disubstituierten Azobenzolen

Cited by 14 publications

References 6 publications

Dediazoniation of Arenediazonium Ions. Part XXII. Reactions of 2, 6‐Dialkyl‐Substituted Benzenediazonium Ions in Super Acids, Acetonitrile and Acetone

Dediazoniation of Arenediazonium Ions. Part XXII. Reactions of 2, 6‐Dialkyl‐Substituted Benzenediazonium Ions in Super Acids, Acetonitrile and Acetone

ChemInform Abstract: STERISCHE HINDERUNG BEI STARK POLAREN 2,6‐DISUBSTITUIERTEN AZOBENZOLEN

Influence of the Z/E configuration on the 13C15N coupling conditions 1J(13C15N) in aromatic azo and diazo compounds

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Influence of the Z/E configuration on the ¹³C¹⁵N coupling conditions ¹J(¹³C¹⁵N) in aromatic azo and diazo compounds