Analyse de la fraction monophénolique des condensats de fumée de cigarettes par association de méthodes chromatographiques

Résumé Les monophénols sont isolés des condensats de fumées de cigarette par chromatographie sur couche mince de Kieselgel G avec un mélange (31) de cyclohexane et d'acétate d'éthyle extraits du support, puis séparé et dosés par chromatographie en phase gazeuse sur colonne capillaire. Le rendement de l;opération est de 80±2% pour le triméthyl 3,4,5 phénol, de 65% pour le triméthyl 2,3,5 phénol. Les teneurs obtenues sont de 8g de phénol, 3g de (para + méta) crésol et 0,5 g de diméthyl 2,6 phénol par mg de condensat. De nombreux autres alkylphénols ont été identifiés.

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Analysis of the monophenolic fraction of tobacco smoke condensates by a combination of chromatographic methods

Summary Monophenols are separated from tobacco smoke condensates by thin-layer chromatography on Kieselgel G using a 31 mixture of cyclohexane and ethylacetate. The monophenolic fraction is recovered from the support and analyzed by GC on a capillary column. The yield is 80±2% for 3,4,5 trimethylphenol and 65% for 2,3,5 trimethylphenol. The concentration determined for phenol, (para+meta) cresol and 2,6 dimethylphenol are 8,3 and 0.5 g per mg of condensate respectively. Numerous other alkyl phenols have been identified.

     

Addition of mercaptans to acetylenic γ-hydroxy ketones

Conclusions Both the nucleophilic and the free radical addition of n-butyl mercaptan to acetylenic-hydroxy ketones (1,1-disubstituted derivatives of 2-pentyn-1-ol-4-one) lead to the formation of the corresponding 1,1-disubstituted derivatives of 2-butylthio-2-penten-1-ol-4-one in 41–65% yield.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1669–1670, July, 1973.     

Ionotropic reactions of β-sultones

The reaction mechanism of-sultones are discussed; a scheme for the reactivity is proposed. Polyfluoro--sultones can undergo anionotropic reactions of the type Hydrogeneous-sultones under prototropic reactions:     

EPR study of melanin-protein interaction: photoinduced free radicals and progressive microwave power saturation.

The photo-induction of free radicals in synthetic L-dihydroxyphenylalanine (L-DOPA) melanin in the presence of bovine serum albumin (BSA) was studied by electron paramagnetic resonance (EPR) spectroscopy. By monitoring the signal intensities and progressive microwave power saturation it was shown that L-DOPA melanin in solution behaves as a single macromolecule, interacting with BSA and molecular oxygen. In the absence of oxygen, the EPR signal of L-DOPA melanin was homogeneously broadened; the magnetic interaction with oxygen induced inhomogeneous broadening. In aqueous solution, the presence of BSA decreased the accessibility of oxygen to paramagnetic centres in the melanin. On UV-visible illumination, the presence of BSA modified the rates of formation and decay of photoinduced free radicals, resulting in a net enhancement of the EPR signal compared with that observed in pure L-DOPA melanin.     

Characteristics of the glucose isomerase from Streptomyces atratus

The molecular mass (Mr) of highly purified glucose isomerase fromStreptomyces atratus has been determined. The native glucose isomerase, which has affinity for xylose, consists of an oligomeric protein containing 1552 amino acid residues and formed of four subunits. The enzyme is stable in the range of temperatures from 40 to 80°C and at pH values of from 6.0 to 11.0.     

Basische Metalle. LXIV. Lewis-basische Bis(trimethylphosphan)cobalt-Komplexe mit Indenyl und Trifluormethylcyclopentadienyl als Liganden

Basic Metals. LXIV. Lewis-basic Bis(trimethylphosphine)cobalt Complexes with Indenyl and Trifluormethylcyclopentadienyl as Ligands The half-sandwich type compounds C₉H₇Co(PMe₃)₂ ( 1 ) and (C₅H₄CF₃)Co(PMe₃)₂ ( 6 ) are prepared from CoCl(PMe₃)₃ and C₉H₇Li or TlC₅H₄CF₃, respectively. They behave like metal bases and react with HBF₄, CH₃I (or CF₃SO₃CH₃), I₂, and CH₃COCl by oxidative addition to give the cationic complexes [C₉H₇CoX(PMe₃)₂]⁺ and [(C₅H₄CF₃)CoX(PMe₃)₂]⁺ (X ? H, CH₃, I, COCH₃) which are isolated as the PF₆ salts ( 2–5 and 7–10 ). The ¹HNMR and the IR spectra of the compounds 1–10 are discussed, also in comparison to those of the corresponding cyclopentadienylcobalt complexes.     

13C NMR study of polarizations and polarization ranges of vinylene groups in seven series of related compounds

Polarizations, polarization ranges and ratios of polarization ranges for vinylene groups in seven series, namely chalcone derivatives, ferrocene analogues of chalcone, stilbene derivatives, ferrocene analogues of stilbene, and styrene derivatives, were studied. The polarization ranges spanning the intervals between ¹³C NMR chemical shifts of the derivatives substituted by p-NO₂ and p-NMe₂ groups are compared in these related compounds. The influence of the side-chain groups in the vinylene moiety and of the sign of the polarization on the substituent-effect are discussed.     

Aminyloxide (nitroxide)-XXVI: ESR-spektroskopische untersuchung von hydrazonyloxiden. Ermittlung der spindichteverteilung

The so-called “Bergmann oxide” 4a and the related compounds 4b-i dissociate reversibly to the corresponding radicals 5 at elevated temperatures. Analysis of the ESR spectra reveals that in 5a-f the unpaired electron is delocalized over the entire molecule. On the other hand the strongly reduced spin density at the β-carbon atom in 5h-i as well as in 7 indicates a twisting about the N,N-bond in these radicals, whereas m 5g the bond between the β-carbon atom and the group Ar¹ is twisted. The results of spin density calculations for radicals 5 are in agreement with the experimentally estimated spin densities. In spin trap experiments with nitrosobenzene or nitrones respectively, 5a reacts at the β-carbon atom, indicating this position as the most reactive one.     

Double asymmetric induction in benchrotrene derivatives

Attachment of a Cr(CO)₃ moiety to one of the aromatic rings in rigid diaryl ketones of very low prochirality followed by addition of a chiral and optically pure reagent leads to satisfactory asymmetric induction ~40%. Asymmetric induction is smaller in the case of acyclic systems.     

Reaction of bis(triethylgermyl)mercury with mercurated acid nitriles

Conclusions The exchange reaction of the radicals between bis(triethylgermyl)mercury and mercury derivatives R₂Hg (R=C(Me₂)CN, C(CF₃)₂CN, CH(CN)₂) leads to the formation of unstable Et₃GeHgR compounds. The composition of the decomposition products of these compounds depends on the nature of R.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2800–2802, December, 1977.