Ueber die Constitution der „Pseudophenole”︁

Auwers, K.

doi:10.1002/cber.190603903134

Cited by 20 publications

(21 citation statements)

References 12 publications

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“…Dyes 1-3, 5 and 7-11 were purchased from Tokyo Kasei Kogyo Co. Ltd or Wako Pure Chemical Industries Ltd, while dyes 4 , 6 and 12 were synthesised. Dyes 4 and 6 were prepared by photochemical rearrangement of azobenzene [20] and by oxidation of 2-phenylindazole [21,22] respectively. Dye 12 was obtained by methylating dye 9.…”

Section: Chemicalsmentioning

confidence: 99%

Degradation of azo dyes by cell‐free extract from Aeromonas hydrophila var. 24B

Yatome

Ogawa

Itoh

et al. 1987

Journal of the Society of Dyers and Colourists

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The degradation of several azo dyes by cell‐free extract from Aeromonas hydrophila var. 24B has been studied. The compounds 4‐dimethylaminoazobenzene, 4‐diethylaminoazobenzene, 2′‐carboxy‐4‐dimethylaminoazo‐benzene, 2′‐carboxy‐4‐diethylaminoazobenzene, 4′‐carboxy‐4‐dimethylaminoazobenzene, and 2′‐methoxy‐carbonyl‐4‐dimethylaminoazobenzene were appreciably degraded by the cell‐free extract. Azobenzene and 4‐carboxyazobenzene were not degraded. Aniline was detected by gas chromatography‐mass spectrometry as a degradation product from 4‐aminoazobenzene and 4‐dimethylaminoazobenzene. 4‐DimethyIaminoaniline was detected by gas chromatography‐mass spectrometry and spectrophotofluorimetry as a degradation product from 2′‐carboxy‐4‐dimethylaminoazobenzene. The cell‐free extract had high substrate specificity for 2′‐carboxy‐4‐dimethylaminoazobenzene.

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Section: Chemicalsmentioning

confidence: 99%

Degradation of azo dyes by cell‐free extract from Aeromonas hydrophila var. 24B

Yatome

Ogawa

Itoh

et al. 1987

Journal of the Society of Dyers and Colourists

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“…101-102" (lit. 181: 1027, 4c is obtained as a colorless oil after evaporation of the hexane and column chromatography (Si02, C6HdMeOH 6 : 1) in 74% yield.…”

Section: Experimental Partmentioning

confidence: 99%

Electrochemical Oxidation of Bis(methylthio)benzenes

Margaretha¹

1979

Helvetica Chimica Acta

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Dedicated to Professor Edgardo Giovannini on the occasion of his 70th birthday (25.VI1.79) SummaryThe bis (methy1thio)benzenes 3a-3c are oxidized to the methylsulfinyl-methylthiobenzenes 4a-4c on a Pt-anode in good yields.In preceding publications [ 11 [2] we had discussed the electrochemical oxidation of some dialkoxybenzenes, e.g. the conversion 1 ---f 2. Although the voltammetric behaviour of the analogous disulfur compounds has been reported in detail The anodic oxidation of some simple sulfides has been investigated [ 5 ] , e.g. thioanisole has been reported to give 74% methylsulfiny1benzr:ne on Pt [6], but for these examples the conventional oxidation of sulfides to sulfoxides by sodium metaperiodate [7] is superior, giving better yields and being easier to handle. We now report on the electrochemical oxidation of the bis (methy1thio)benzenes 3a-3c.Electrolysis of these compounds in MeOH/THF 5 : 1, the latter being added for solubility reasons, or in CH,CN/H20 99 : 1 on Pt-electrodes with tetraethylammoniumperchlorate (TEAP) as electrolyte leads to the formation of the methylsulfinyl-methylthiobenzenes 4a-4c in good yields, the oxidation of the second methylthio group or of the sulfoxide to the sulfone beginning to compete after a much higher degree of conversion 3 + 4 than with any chemical oxidizing agent. For illustration, 4a had only been obtained from 3a in a four-step reaction [8], while compounds as 4b and 4c had not been isolated at all, only the bis(methy1-sulfony1)benzenes being known. The electrochemical oxidation of 3a-3c to 4a-4c being much more selective than any chemical oxidation is i.herefore a synthetic useful reaction. NMR.-and mass-spectral data of 4a-4c are summarized in the Tuble.In contrast to compounds like 1, no anodic addition [91 has been observed with 3a-3c. In methanolic KOH no conversion 3 + 4 takes place, presumably due to reduction of the radical cation by the nucleophile CH,O-. Acetate or pyridine also did not add to the aromatic ring. No benzylic substitution was observed with either 3c or the monothiomethyl compound 3d. Less than 5% of 2 were detected after oxidation of 3 e in MeOH, arising most probably from an anodic substitutiodanodic addition sequence. All these results indicate that the positive

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“…Their experiment seems to be the first example of pyrazoline formation by the reaction of an α,β-enone with a hydrazine derivative. Later, Auwers et al [2,3] corroborated that the product of this reaction was 1-phenyl-2-pyrazoline. During the last century, after these pioneering studies, numerous 2-pyrazolines were synthesized by the reaction of α,β-enones with hydrazines.…”

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confidence: 92%

“…Concerning the synthesis of pyrazolines, the second milestone was the discovery of the reaction of the diazoalkanes with α,β-unsaturated carboxylic acid derivatives [4][5][6][7] and α,β-enones [8,9] in the early twentieth century. Among dia-zoalkanes, diazomethane proved to be the most convenient nitrogen-containing reagent making available the preparation of a wide variety of 1-pyrazolines as primary products which spontaneously isomerize or can be converted into their appropriate 2-pyrazoline isomers [10][11][12][13][14].…”

mentioning

confidence: 99%