The first dissociation constant of oligonuclear phenolic compounds consisting of one nitrophenol unit besides further alkyl phenol units (10 dinuclear, 15 trinuclear, 6 tetranuclear compounds, and 4 nitrophenols as model) was determined spectroscopically in water/methanol (50/50 by vol.) at 25°C. For the ortho-linked title compounds with the nitrophenol unit at the end of the molecule a decrease of pK1 is observed which becomes stronger with increasing chain length. The introduction of bulky groups in ortho-position of the dissociating phenolic unit, as well as at the opposite end of the molecule causes a further decrease of pK1. The lowest value is found for a p-nitrophenol unit in the mid…

Strukturaufklärung der bei der Addition von 2-Cyano-2-propylradikalen an p-Tolyl- und 4-Cyclohexylphenyl-methacrylat entstehenden Produkte mittels 1H NMR- und Massenspektren

The chromatographically pure products, gained on the suppression of polymerisation of p-tolyl or 4-cyclohexylphenyl methacrylates (1, 2) by a great excess of 2-cyano-2-propyl radicals, could be isolated in a total yield of 95 to 100%. The structure of these products was established by 1H NMR and mass spectroscopy. There are p-tolyl or 4-cyclohexylphenyl 4-cyano-2-(2-cyano-2-propyl)-2,4-dimethylvalerate (1a, 2a), p-tolyl or 4-cyclohexylphenyl 2-(2-cyano-2-methylpropyl)acrylate (1b, 2b), p-tolyl or 4-cyclohexylphenyl 4-cyano-4-methyl-2-(2-cyano-2-methylpropyl)valerate (1c, 2c), p-tolyl or 4-cyclohexylphenyl 4-cyano-2,4-dimethylvalerate (1d, 2d), and p-tolyl or 4-cyclohexylphenyl 4-cyano-2,4-d…

Verschiedenartige Additionsreaktionen von 2-Cyano-2-propylradikalen an p-Tolylmethacrylat und 4-Cyclohexylphenylmethacrylat

Durch Umsetzung von p-Tolylmethacrylat oder 4-Cyclohexylphenylmethacrylat in stark verdunnter, siedender Benzollosung mit einem sehr grosen Uberschus an 2,2′-Azoisobutyronitril wurden die erwarteten Additionsprodukte mit 2-Cyano-2-propylradikalen (1) erhalten, namlich p-Tolyl- bzw. 4-Cyclohexylphenyl-[4-cyano-2-(2-cyano-2-propyl)-2,4-dimethyl]valerianat (3a bzw. 3b) mit rund 50% Ausbeute. Daneben wurden p-Tolyl- bzw. 4-Cyclohexylphenyl-(4-cyano-4-methyl-2-methylen)valerianat (4a bzw. 4b), p-Tolyl- bzw. 4-Cyclohexylphenyl-[4-cyano-2(2-cyano-2-methyl-1-propyl)-4-methyl]valerianat (5a bzw. 5b), p-Tolyl- bzw. 4-Cyclohexylphenyl-(4-cyano-2,4-dimethyl)valerianat (6a bzw. 6b) und p-Tolyl- bzw. 4-C…

Spektroskopische analyse mehrfacher methacrylsäureester von oligo[(2-hydroxy-1,3-phenylen)methylen]en mittels UV-, IR-, 1H NMR- und massenspektren

The structures of two homologous series of oligo[(2-hydroxy-1,3-phenylene)methylene]s completely esterified with methacrylic acid, were spectroscopically analysed. The molar decadal absorption coefficients of ultraviolet absorption maxima of the two homologous series confirm Hunter's relation. The vinylidene, ester, and substitution bands of the infrared spectra as well as the mass spectra agree with the accepted structures. The 1H NMR spectra permit to differentiate between exterior and interior groups of the molecules.

Nebenreaktionen der radikalisch ausgelösten Cyclisierung von 2,2′-Methylen-bis(4-methyl-1,2-phenylen)-dimethacrylat

2,2′-Methylene-bis(4-methyl-1,2-phenylene) dimethacrylate (1) was reacted with an excess of 2,2′-azoiso-butyronitrile (mole ratio 1:15) highly diluted in boiling benzene. The reaction products were separated by column chromatography. It was found that the 1-cyano-1-methylethyl radical induced the cyclization of 1 to yield the product of a head to tail addition (2) in 55% yield. In addition, the product of a head to head addition (3) was isolated in 4% yield. 35% of 1 reacted in the same way as it has already been observed as suppression of polymerization in the case of p-tolyl methacrylate to give the products 4 and 5. The structures of the products were confirmed by elemental analyses, by …

Eine einfache, vollstäundige Veresterung von Oligo[(2-hydroxy-1,3-phenylen)methylen]en mit Methacryloylchlorid

Die Darstellung phenolischer Methacrylsaureester verlauft glatt und mit Reinausbeuten bis zu 95%, wenn die in gekuhltem Benzol (5—10°C) in Gegenwart von Triathylamin gelosten phenolischen Verbindungen mit Methacryloylchlorid umgesetzt werden. So wurden neben drei einfachen Phenylmethacrylaten zehn vollstandig veresterte Oligo[(2-hydroxy-1,3-phenylen)methylen]e erhalten. Phenyl methacrylates can easily be prepared with yields of pure esters up to 95% by reaction of the phenolic compounds with methacryloyl chloride in cooled benzene (5—10°C) in the presence of triethylamine. Three simple phenyl methacrylates and ten oligo[(2-hydroxy-1,3-phenylene)methylene]s completely esterified by methacryl…

Darstellung von Oligo[(hydroxy-1,3-phenylen)methylen]en mit Hydroxynitrophenylen- und Alkylhydroxyphenyleneinheiten

Possibilities to synthesize substituted oligo[(hydroxy-1,3-phenylene)methylene]s containing hydroxynitrophenylene and alkylhydroxyphenylene units are discussed. The only successful way to introduce the hydroxynitrophenylene unit consists in the condensation of chloromethylated nitrophenols with an excess of alkylphenols. The resulting compounds can be prolonged stepwise at the alkylhydroxyphenylene end group by alternating hydroxymethylation and further condensation with alkylphenols. Thus, including the hydroxymethylated compounds, 11 dinuclear, 17 trinuclear, and 5 tetranuclear compounds were obtained for the first time. Some of them were characterized by their acetyl derivatives.