Synthèses dans la série des constituants odorants caractéristiques de l'essence absolue de cassie (Acacia farnesiana WILLD.): Les acides méthyl-3-décène-3-oïques cis et trans,méthyl-3-décène-4-oïques cis et trans,et les quatre méthyl-3-décénols-1 correspondants

Three new fragrant compounds formerly isolated from the absolute oil of cassie (Acacia farnesiana WILLD .) have been synthesized through stereospecific reactions, and their respective structures thus confirmed. These unusual C₁₁ constituents are cis-3-methyl-dec-3-enoic acid (Ia), trans-3-methyl-dec-4-enoic acid (IIa) and cis-3-methyl-dec-3-en-1-ol (Ib). The related ‘non natural’ stereomers, namely, trans-3-methyl-dec-3-enoic acid (X) and cis-3-methyl-dec-4-enoic acid (XIX), have also been synthesized, as well as the 3-methyl-decen-1-ols IIb, XVII and XX.     

Fluorénacènes et fluorénaphènes synthèses dans la série des indéno-fluorènes,XVII. Dérivés méthylés du cis-fluorénacène,du trans-fluorénacène et du trans-fluorénaphène

By condensation of the chlorides of the three 9-oxo-fluorene-2-, -3-, and -4-carboxylic acids with 4-bromo-1,2-xylene on one side, and of the chlorides of o-bromobenzoic acid, 2-bromo-4-methyl-benzoic acid and 2-bromo-4,5-dimethyl-benzoic acid with fluorene, 2-methylfluorene and 3-methylfluorene on the other side, followed by direct or indirect cyclisation and by final reduction, several new methyl derivatives of the indenofluorenes I, II and IV are synthesized.     

Synthèse de sucres aminés ramifiés. IV Synthèse de quelques dérivés nouveaux par l'intermédiaire d'une hexose-spiro-aziridine

Treatment of 3-C-cyano-1,2:5,6-di-O-isopropylidene-3-O-(toluene-p-sulfonyl)-α-D -allofurannose with AlLiH₄ yields a sugar-spiro-aziridine and a branched chain sulfonamide. Reaction mechanisms are briefly discussed and the configurations of the products obtained are proved by chemical reactions. With hydrogenation, the spiro compound is opened to a branched chain amino sugar with the same tertiary carbon as in vancosamine. Several derivatives of this new compound are described: the 6-deoxy sugars in series L and D and the pentose resulting from its oxidation by periodic acid. The conformation around C(4)–C(5) bond is deduced for three compounds from NMR. data.     

Réactions de Friedel et Crafts de dérivés aromatiques sur les composés dioxo-1,4,2,3-non saturés. IV. Réactions des hydroxy-5-ouchloro-5-diméthyl-3,5- ou diméthyl-4,5-dihydro-2,5-furannones-2

Friedel-Crafts reactions of aromatic derivatives with 1,4-dicarbonyls 2,3-éthylenic compounds. Part IV. Reactions of 5-hydroxy or 5-chloro 3,5-dimethyl or 4,5-dimethyl 2 (5 H) furanones We studied the Friedel-Crafts reactions of 2-(5H)-furanones. In the presence of sulfuric acid and of an aromatic derivative, 5-hydroxy- or 5-chloro-5-methyl-2-(5H)-furanones with one methyl group either in the 3 position, or in the 4 position generally give the corresponding 5-aryl-2-(5H)-furanones, while with aluminium chloride, it is possible to obtain, when a reaction takes place, isomeric 1H-indenecarboxylic acids. However, in a particular case, an addition to the substrate's double bond is observed. The 3-aryl-5-hydroxy-tetrahydrofuran-2-one obtained is methylated in two ways and gives either a cyclic product, or a linear one. In two cases tautomerism between 1H-1-indenecarboxylic acid and 1H-3-indenecarboxylic has been shown by ¹H-NMR.     

Analysis of catechins in Theobroma cacao beans by cyclodextrin-modified micellar electrokinetic chromatography

A micellar electrokinetic chromatography (MEKC) method was developed for the quantitation of polyphenols (+)-catechin and (-)-epicatechin (catechin monomers) and the methylxanthine theobromine in Theobroma cacao beans. Owing to the poor stability of catechin monomers in alkaline conditions, a 50 mM Britton-Robinson buffer at a pH 2.50 was preferred as the background electrolyte. Under these conditions, the addition of hydroxypropyl-beta-cyclodextrin (HP-beta-CD) at a concentration of 12 mM to the SDS micellar solution (90 mM), resulted in a cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC) endowed with two peculiar advantages compare to the conventional MEKC: (i) strong improvement of separation of the most important phytomarkers of T. cacao and (ii) enantioselectivity toward (+/-)-catechin. In particular, separation of methylxanthines (theobromine and caffeine), procyanidin dimers B1 and B2, and catechins (epicatechin and catechin) was obtained simultaneously to the enantioseparation of racemic catechin within 10min. The enantioselectivity of the method makes it suitable in evaluation of possible epimerisation at the C-2 position of epicatechin monomer potentially occurring during heat processing and storage of T. cacao beans. The extraction procedure of the phytomarkers from the beans was approached using ultrasonic bath under mild conditions optimized by a multivariate strategy. The method was validated for robustness, selectivity, sensitivity, linearity, range, accuracy and precision and it was applied to T. cacao beans from different countries; interestingly, the native enantiomer (+)-catechin was found in the beans whereas, for the first time we reported that in chocolate, predominantly (-)-catechin is present, probably yielded by epimerisation of (-)-epicatechin occurred during the manufacture of chocolate.     

Thermische Umlagerungen von (+)-Isopinocampheol und (−)-Isopinocamphon

Short-path thermolysis of (+)-isopinocampheol ( 1 ) at about 330° in the gas phase yields mainly (—)-(3 S, 4 S)-3, 7-dimethyl-octa-1,6-dien-4-ol ( 2 ). Longer heating of 2 at about 290–330° yields as main products the diastereoisomeric hydroxy-Δ⁸-iridenes 3, 4 and 5 in ratios dependent on temperature. Above 400°, formation of 4-methylpent-3-en-1-al ( 7 ) and 2-butene ( 8 ) predominates. Compounds 7 and 8 also appear as the stable final thermolysis products of 3, 4 and 5 above 500°. Small quantities of (+)-iso-dihydrocarveol ( 6 ) always occur as by-product in the thermolysis of 1 . Short-path thermolysis of (—)-isopinocamphone ( 13 ) at about 430° leads, with slight epimerisation, to the three diastereoisomeric oxo-Δ⁸-iridenes 15, 18 and 17 via (+)-(3 S)-3, 7-dimethylocta-1, 6-dien-4-one ( 14 ). Structure and stereochemistry of all reaction products are established spectroscopically and chemically.     

Synthèse de deux nouveaux acides amines phénoliques comportant un cycle 1,2,4-oxadiazole

Synthesis of two phenolic amino acids containing the 1,2,4-oxadiazole ring The synthesis of α-amino-β [3-(p-hydroxyphenyl)-1,2,4, oxadiazol-5-yl]propionic acid (9) and its β-amino isomer (10) (see scheme 3) is reported. By condensation of p-benzyloxy-benzamide oxime and N-benzyloxycarbonyl asparagine the derivatives 4 and 5 (see scheme 1) are obtained leading after deprotection to 9 and 10 . The synthesis of N-carboxyanhydride of 4 (6) and its corresponding amino acid (7) and amide (8) is also described.     

Conversion of 11-keto-9-beta, 10-alpha-steroids on 10-alpha-compounds. Synthesis of 10-alpha-cortisone, 11-oxo-10-alpha-progesterone, 10-alpha-androsterone and analogs of 11-hydroxy-compounds

Isomerisation of 11-keto-9β, 10α(retro)-steroids by acid or base led to the thermo-dynamically more stable 11-keto-10α-isomers, which have not yet been described in the literature. This epimerisation at C-9 constitutes a new route for the synthesis of 10α-steroids. The steric factors responsible for this isomerisation are discussed.     

Studies on Binary Blends of Poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) and Natural Polyphenol Catechin: Specific Interactions and Thermal Properties

The existence of a specific intermolecular hydrogen‐bonding interaction between poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) [P(3HB‐co‐3HH)] and (+)‐catechin in their blends was demonstrated by Fourier‐transform infrared spectroscopy (FT‐IR). It was found that the experimentally estimated fraction of hydrogen‐bonded carbonyl groups was much lower than the theoretically predicted maximum fraction. Only one glass transition temperature (T_g) occurred in the blends with the compositions detected by differential scanning calorimetry (DSC), being further confirmed by the results of dynamic mechanical thermal analysis (DMTA). The decrease of the melting point (T_m) and the increase of the glass transition temperature of the blends observed by the DSC measurements also suggested the existence of a strong intermolecular interaction. It was interesting to note that, as a low‐molecular‐weight compound, catechin showed a glass transition, which arises from strong self‐association. As expected, the crystalline structure of P(3HB‐co‐3HH) in the blends showed no change, but the crystallinity of the copolymer component in the blends, calculated by wide‐angle X‐ray diffraction, decreased with the increase of catechin weight content. Investigated by tensile experiments, the maximum strength and modulus decreased sharply with the increase of catechin content; on the contrary, the elongation changed slowly.

The FT‐IR spectra in the wave‐number 1 680–1 780 cm^?1 region for blends of P(3HB‐co‐3HH)/catechin. A: HBH; B: HBHC10; C: HBHC20; D: HBHC30; E: HBHC40; F: HBHC50; and G: catechin.     

Interactions intramoléculaires. XXVI—Constantes de couplage et hétérogénéités conformationnelles dans une série de R-3 et R-5 cyano-4 cyclohexènes deutériés (R=méthyl ou t-butyl)

For trans-3-R- and 5-R-1-acetoxy-4-cyanocyclohexene-6,6-d₂ the molar fractions of diequatorial conformers are 0.83 (3-methyl), 0.68 (5-methyl), 0.57 (3-tert-butyl) and 0.55–0.69 (5-tert-butyl). For the last two compounds the values of the coupling constants are in agreement with the hypothesis of an ee?aa equilibrium. For the cis isomers, the molar fractions of equatorial alkyl conformers are 0.76 (3-methyl and 5-methyl) and 1.0 (3-tert-butyl and 5-tert-butyl). The cis-1-acetoxy-3-tert-butyl-4-methoxycarbonyl-cyclohexene presents a conformational heterogeneity. The conformational free energy of the methyl group in position 4 has been evaluated as ?0.6 kcal mol^?1 (2.5 kJ mol^?1).     

Synthèses stéréospécifiques et étude organoleptique comparée de onze triméthyl-2,2,3-exo-norbornyl-5-exo-cyclohexanols racémiques

The stereospecific syntheses of the eleven racemic 2,2, exo-3-trimethyl-exo-5-norbornyl-cyclohexanols related to the formula VI have been achieved. Moreover, the fragrant properties of these isomeric and stereomeric cyclohexanols have been carefully estimated by a team of four well-experienced perfumers. In good agreement with our earlier observations [1 ab], it was concluded that the axial 3-(2,2, exo-3-trimethyl-exo-5-norbornyl)-cyclohexanols, threo (XXIV) and erythro (XXIX), are the only isomers which display a very powerful and genuine sandalwood odour. The other cyclohexanols were found to be about 20–100 times less fragrant (4 compounds), or practically odourless (5 compounds).     

Le diméthyl- et le diéthyl-tétracarbonylosmium Synthèse et réactivité

The sodium salt Na₂[Os(CO)₄] has been obtained in high yields by the reduction of either OsH₂(CO)₄ or Os₃(CO)₁₂ with sodium sand in the presence of catalytic amounts of 2, 2′-bipyridyle. The reaction of Na₂[Os(CO)₄] with alkylating agents such as methyl and ethyl iodide produces OsR₂(CO)₄ (R = CH₃, C₂H₅). NMR. and IR. spectra indicate a cis-octahedral structure of symmetry C_2v for these new alkyl compounds. Bromine breaks one osmium-carbon bond in cis-Os(CH₃)₂(CO)₄ to give cis-OsCH₃Br(CO)₄, whereas in cis-Os(C₂H₅)₂(CO)₄ both ethyl groups are easily displaced by bromine to give cis-OsBr₂(CO)₄. Under CO pressure and at elevated temperature cis-Os(CH₃)₂(CO)₄ is converted to Os(CO)₅ and ethane. With cis-Os(C₂H₅)₂(CO)₄ two CO are inserted in osmium-carbon bonds to give . NMR. and IR. data suggest a cis-configuration for this derivative and the possibility of the presence of rotational isomers.     

Synthèse énantiospécifique des acides (+)-(2R)- et (−)-(2S)-éthyl-6-dihydro-3,4-méthyl-2-oxo-4–2H pyranecarboxylique-5

Enantiospecific Synthesis of (+)-(2R)- and (?)-(2S)-6-Ethyl-3,4-dihydro-2-methyl-4-oxo-2H-pyran-5-carboxylic Acid The two enantiomers (?)-(2S)- and (+)-(2R)-6-ethyl-3,4-dihydro-2-methyl-4-oxo-2H-pyran-5-carboxylic acid ((S)- and (R)- 7 ) have been synthesized from (+)-(3S) and (?)-(3R)-3-hydroxybutanoates, respectively (Scheme 1). By reduction and decarboxylation, the tetrahydro-2H-pyranols (2R, 4R, 6S)- and (2S, 4S, 6R)- 13 , respectively, were obtained with an enantiomeric excess of ≥ 93%.     

Hydrogen‐Bonding Interaction and Crystalline Morphology in the Binary Blends of Poly(ε‐caprolactone) and Polyphenol Catechin

The specific intermolecular hydrogen‐bonding interaction between the ester carbonyl groups of poly(ε‐caprolactone) (PCL) and the phenolic hydroxyl groups of catechin has been studied by Fourier‐transform infrared spectroscopy (FT‐IR) and differential scanning calorimetry (DSC). According to quantitative curve‐fitting analysis of the FT‐IR spectra of PCL/catechin blends, it was found that the fraction of hydrogen‐bonded carbonyl groups of PCL increased with catechin content, while that of hydrogen‐bonded hydroxyl groups of catechin decreased. The calculated crystallinity of PCL in the binary blends, based on the curve‐fitting results, suggested that the crystallization of PCL was restrained in the blends with catechin. Only single glass transition temperature, T_g, was observed over the whole range of blend compositions, which was between those of the pure components. The melting point, T_m, depressed and T_g increased, indicating also the existence of strong intermolecular association. The blend composition dependence of T_g could be predicted very well by the Kwei equation with a positive ‘q’ value of 124. With the aid of small angle X‐ray scattering measurement, the segregation of catechin was investigated. It was found that the extent of extra‐lamellar segregation increased with catechin content. It was suggested that the crystal growth rate played the dominant role in the formation of morphology. With decreasing crystal growth rate of PCL component in the blends, enough time has been given to catechin molecules to diffuse into extra‐lamellar region.

     

高效液相色谱法测定绿茶中茶多酚及咖啡因

应用高效液相色谱法测定绿茶中没食子酸(GA)、咖啡因(CAF)及5种儿茶素类化合物,包括儿茶素(C)、表儿茶素(EC)、表没食子儿茶素没食子酸酯(EGCG)、表儿茶素没食子酸酯(ECG)、没食子儿茶素没食子酸酯(GCG)。对国家标准方法GB/T 8313-2008中流动相组成进行了调整,用0.5%乙酸代替2%的乙酸,在AT.Lichrom ODS色谱柱(4.6mm×250mm,5μm)上进行分离,流量为1.0mL.min-1,在波长278nm处进行紫外检测。7种组分在40min内达到完全分离。7种组分的质量浓度分别在一定的范围内与其峰面积呈线性关系。方法用于绿茶的分析,7种组分的加标回收率在96.0%～102.8%之间。     

Interactions intramoleculaires. XXI—Constantes de couplage et interactions gauches avec un groupement t-butyle (molécules cyclohexaniques deutériées)

Different isotopic modifications of deuterated products of 1-t-butlyl-4-methoxycarbonyl cyclohexene (d₄-3,3,6,6), cis- and trans-3-methyl-4-cyanocyclohexene (d₃-3,6,6), cis- and trans-3-methyl-4-cyanocyclohexene (d₃,6,6), cis- and trans-3-t-butyl-4-methoxycarbonylcyclohexene (d₃,-3,6,6) are shown by nuclear magnetic resonance spectral analysis. By comparison of ³J and ⁴J coupling constants of model molecules and molecules with large gauche interactions, we obtain proof that the latter are in a chair conformation with moderate cycle deformations.     

The profiling and identification of the metabolites of (+)‐catechin and study on their distribution in rats by HPLC‐DAD‐ESI‐IT‐TOF‐MSn technique

(+)‐Catechin, a potential beneficial compound to human health, is widely distributed in plants and foods. A high‐performance liquid chromatography with diode array detector and combined with electrospray ionization ion trap time‐of‐flight multistage mass spectrometry method was applied to profile and identify the metabolites of (+)‐catechin in rats and to study the distribution of these metabolites in rat organs for the first time. In total, 51 phase II metabolites (44 new) and three phase I metabolites were tentatively identified, comprising 16 (+)‐catechin conjugates, 14 diarylpropan‐2‐ol metabolites, 6 phenyl valerolactone metabolites and 18 aromatic acid metabolites. Further, 19 phase II metabolites were new compounds. The in vivo metabolic reactions of (+)‐catechin in rats were found to be ring‐cleavage, sulfation, glucuronidation, methylation, dehydroxylation and dehydrogenation. The numbers of detected metabolites in urine, plasma, small intestine, kidney, liver, lung, heart, brain and spleen were 53, 23, 27, 9, 7, 5, 3, 2 and 1, respectively. This indicated that small intestine, kidney and liver were the major organs for the distribution of (+)‐catechin metabolites. In addition, eight metabolites were found to possess bioactivities according to literature. These results are very helpful for better comprehension of the in vivo metabolism of (+)‐catechin and its pharmacological actions, and also can give strong indications on the effective forms of (+)‐catechin in vivo. Copyright © 2013 John Wiley & Sons, Ltd.     

Kopsirachin,ein ungewöhnliches Alkaloid aus der Apocynaceae Kopsia dasyrachis Ridl. 189. Mitteilung über organische Naturstoffe

Kopsirachine, an Unusual Alkaloid from the Apocynaceae Kopsia dasyrachis Ridl. From the leaves of Kopsia dasyrachis Ridl. a new type of alkaloid, kopsirachine ( 1 ), built up from catechin ( 2 ) and skytanthine ( 3 ) has been isolated. The structure elucidationis based on spectral and chemical evidence. Oxidative cleavage of its derivative 4 with KMnO₄ afforded veratric acid wich was identified as its methylester by comparison with an authentic sample. Pyrolysis of 1 yielded δ-skytanthine ( 3 ). The stereochemistry of the skytanthine substituents in 1 could not yet be established.     

Déconjugaison d'énones dérivées de sucres Communication préliminaire

Deconjugation of sugars enones. Preliminary Communication Branched-chain sugar enones 1 and 2 ( R = Ac) deconjugated toposelectively (only the E isomers reacting) to 3 . The same phenomenon was noted in the case of Z- 4 which gave E- 5 . The kinetic parameters of these reactions favored a concerted mechanism, i.e. a [1, 5]-sigmatropic shift.     

Sur le mécanisme de la réaction de meth-cohn-tarnowski de préparation des thiocoumarines

Reaction of 2-t-butylthiobenzaldehyde with N-(2-dialkylaminoethyl)-cyanacetamides followed by heating of the resulting 3-(2-t-butylthiophenyl)-2-cyanoacrylamides in polyphosphoric acid leads to the formation of 3-carboxamido-2-imino-2H-benzo[b][l]thiopyrann intermediates which afford thiocoumarins on hydrolysis. The authors postulate the intermediate formation of a thiophenate ion by an electronic mechanism involving six centers.