- Isolation, characterization and structure of a new allenic polyine antibiotic produced by fungus LL-07F275
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Antibiotic 07F275 (1), produced by submerged fermentations of fungal culture LL-07F275, was isolated and characterized despite its inherent instability. Its UV spectrum was identical with that of nemotin, a member of the allenic polyacetylene family, but a molecular weight of 218 daltons indicated a new compound. Structure 1 was determined on the basis of spectroscopic evidence, particularly NMR. Since 1 is a thirteen carbon-containing allenic diyne, it is closely related to mycomycin.
- Schlingmann,Milne,Pearce,Borders,Greenstein,Maiese,Carter
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- Nickel(=)-induzierte CC-Verknuepfung von CO2 mit 1,3-Butadien zu linearen C13-Saeuren
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Fluorinated pyridine-nickel(0)-systems induce a new coupling reaction between 1,3-butadiene and carbon dioxide.Linear C13-acids with three or four CC double bonds and terminal carboxylic groups can be prepared stoichiometrically in this way.
- Hoberg, Heinz,Baerhausen, Dieter
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Read Online
- Sterically hindered (pyridyl)benzamidine palladium(II) complexes: Syntheses, structural studies, and applications as catalysts in the methoxycarbonylation of olefins
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Reactions of ligands (E)-N′-(2,6-diisopropylphenyl)-N-(4-methylpyridin-2-yl)benzimidamide (L1), (E)-N′-(2,6-diisopropylphenyl)-N-(6-methylpyridin-2-yl)benzimidamide (L2), (E)-N′-(2,6-dimethylphenyl)-N-(6-methylpyridin-2-yl)benzimidamide (L3), (E)-N′-(2,6-dimethylphenyl)-N-(4-methylpyridin-2-yl)benzimidamide (L4), and (E)-N-(6-methylpyridin-2-yl)-N′-phenylbenzimidamide (L5) with [Pd(NCMe)2Cl2] furnished the corresponding palladium(II) precatalysts (Pd1–Pd5), in good yields. Molecular structures of Pd2 and Pd3 revealed that the ligands coordinate in a N^N bidentate mode to afford square planar compounds. Activation of the palladium(II) complexes with para-tolyl sulfonic acid (PTSA) afforded active catalysts in the methoxycarbonylation of a number of alkene. The resultant catalytic activities were controlled by the both the complex structure and alkene substrate. While aliphatic substrates favored the formation of linear esters (>70%), styrene substrate resulted in the formation of predominantly branched esters of up to 91%.
- Akiri, Saphan O.,Ojwach, Stephen O.
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- Tunable aryl imidazolium ionic liquids (TAIILs) as environmentally benign catalysts for the esterification of fatty acids to biodiesel fuel
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Herein, we describe the synthesis of tunable aryl imidazolium ionic liquid catalysts and tested for esterification of fatty acids to biodiesel. In this work, six tunable aryl imidazolium ionic liquids (TAIILs) 1a-1f were prepared. These ionic liquids were used as the economical and reusable catalysts for the synthesis of biodiesel fuels. The reaction has been preceded in a monophase at 80 °C for 4 h, after which the product was separated from the catalyst system by a simple liquid/liquid phase separation at room temperature with excellent yields. With the simple post-process, the catalyst is reusable at least 6 times. This novel method offers a short reaction time, good yields, and environmentally benign characteristics.
- Ho, Wen-Yueh,Lin, Wesley,Lin, Yi-Jyun,Luo, Shun-Yuan,Pantawane, Amit,Su, Po-Fang,Thul, Mayur,Tseng, Shao-An,Wu, Hsin-Ru
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- Method for preparing organic carboxylic ester through combined catalysis of aryl bidentate phosphine ligand
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The invention discloses a method for preparing organic carboxylic ester by combined catalysis of an aryl bidentate phosphine ligand. The method comprises the following steps: under the action of a palladium compound/aryl bidentate phosphine ligand/acidic additive combined catalyst, carrying out a hydrogen esterification reaction on terminal olefin, carbon monoxide and alcohol so as to generate theorganic carboxylic ester with one more carbon than olefin. According to the invention, by adoption of the palladium compound/aryl bidentate phosphine ligand/acidic additive combined catalyst, good catalytic activity and selectivity for the hydrogen esterification reaction of the olefin are achieved, and olefin carbonylation to synthesize organic carboxylic ester can be efficiently catalyzed. Thearyl bidentate phosphine ligand has a rigid skeleton structure of a rigid ligand and the flexibility of a flexible ligand, so the aryl bidentate phosphine ligand has proper flexibility due to the characteristic that the aryl bidentate phosphine ligand is soft and rigid, and a most favorable coordination mode and a stable active structure in space are favorably formed. In addition, the aryl bidentate phosphine ligand has the advantages of high stability, simple and convenient synthesis method and the like; and a novel industrial technology is provided for production of organic carboxylate compounds.
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Paragraph 0046
(2020/05/29)
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- Two-way homologation of aliphatic aldehydes: Both one-carbon shortening and lengthening via the same intermediate
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Aliphatic aldehydes can be homologated to both one-carbon shorter and one-carbon longer homologous carbonyl compounds through the 2–4 steps of reactions via the same intermediates, β,γ-unsaturated α-nitrosulfones, prepared from the proline-catalyzed sequential reactions of several aliphatic aldehydes with phenylsulfonylnitromethane. While the oxidative cleavage of the key intermediates gave one-carbon less homologous carbonyl compounds, the reduction of the same key intermediates followed by an oxidation produced one-carbon more homologous carbonyl compounds.
- Yoo, Jae Won,Seo, Youngran,Park, Jong Beom,Kim, Young Gyu
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- Structure determination of fatty acid ester biofuels via in situ cryocrystallisation and single crystal X-ray diffraction
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In situ cryocrystallisation in combination with a zone-melting technique enabled the crystal structure determination of a homologous series of low-melting n-alkyl methyl esters Cn-1H2n+1CO2CH3, from methyl pentanoate (n = 5) to methyl tridecanoate (n = 13), by single crystal X-ray diffraction. Two isostructural groups were identified: the odd-numbered triclinic members (C9,11,13) and the even-numbered orthorhombic members (C8,10,12). All observed structural trends, similarities and differences in intermolecular contacts, including the odd-even effect observable in melting point behaviour and unit cell parameters, were easily visualised and described by 2D fingerprint plots generated from the calculated Hirshfeld surfaces, in combination with atom-atom Coulomb-London-Pauli (AA-CLP) lattice energy calculations.
- Prathapa, Siriyara Jagannatha,Slabbert, Cara,Fernandes, Manuel A.,Lemmerer, Andreas
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- Medium-chain fatty acids from Eugenia winzerlingii leaves causing insect settling deterrent, nematicidal, and phytotoxic effects
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Eugenia winzerlingii (Myrtaceae) is an endemic plant from the Yucatan peninsula. Its organic extracts and fractions from leaves have been tested on two phloem-feeding insects, Bemisia tabaci and Myzus persicae, on two plant parasitic nematodes, Meloidogyne incognita and Meloidogyne javanica, and phytotoxicity on Lolium perenne and Solanum lycopersicum. Results showed that both the hexane extract and the ethyl acetate extract, as well as the fractions, have strong antifeedant and nematicidal effects. Gas chromatography-mass spectrometry analyses of methylated active fractions revealed the presence of a mixture of fatty acids. Authentic standards of detected fatty acids and methyl and ethyl derivatives were tested on target organisms. The most active compounds were decanoic, undecanoic, and dodecanoic acids. Methyl and ethyl ester derivatives had lower effects in comparison with free fatty acids. Dose-response experiments showed that undecanoic acid was the most potent compound with EC50 values of 21 and 6 nmol/cm2 for M. persicae and B. tabaci, respectively, and 192 and 64 nmol for M. incognita and M. javanica, respectively. In a phytotoxicity assay, medium-chain fatty acids caused a decrease of 38-52% in root length and 50-60% in leaf length of L. perenne, but no effects were observed on S. lycopersicum. This study highlights the importance of the genus Eugenia as a source of bioactive metabolites for plant pest management.
- Cruz-Estrada, Angel,Ruiz-Sánchez, Esaú,Cristóbal-Alejo, Jairo,González-Coloma, Azucena,Andrés, María Fe,Gamboa-Angulo, Marcela
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- Metathesis of renewable polyene feedstocks – Indirect evidences of the formation of catalytically active ruthenium allylidene species
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Cross-metathesis (CM) of conjugated polyenes, such as 1,6-diphenyl-1,3,5-hexatriene (1) and α-eleostearic acid methyl ester (2) with several olefins, including 1-hexene, dimethyl maleate and cis-stilbene as model compounds has been carried out using (1,3-bis-(2,4,6-trimethylphenyl)-2-imidazolidinylidene)-dichloro(o-isopropoxyphenylmethylene)ruthenium (Hoveyda-Grubbs 2nd generation, HG2) catalyst. The feasibility of these reactions is demonstrated by the observed high conversions and reasonable yields. Thus, regardless of the relatively low electron density, =CH–CH= conjugated units of molecules, including compound 2 as a sustainable, non-foodstuff source, can be utilized as building blocks for the synthesis of various value-added chemicals via olefin metathesis. DFT-studies and the product spectrum of the self-metathesis of 1,6-diphenyl-1,3,5-hexatriene suggest that a Ru η1-allylidene complex is the active species in the reaction.
- Kovács, Ervin,Sághy, Péter,Turczel, Gábor,Tóth, Imre,Lendvay, Gy?rgy,Domján, Attila,Anastas, Paul T.,Tuba, Róbert
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supporting information
p. 213 - 217
(2017/09/12)
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- Dammarane triterpenoids from Carnauba, Copernicia prunifera (Miller) H. E. Moore (Arecaceae), wax
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Phytochemical investigation from carnauba (Copernicia prunifera) wax led to the identification of sixteen dammarane–type triterpenes, including thirteen new characterized as: (24R*)-methyldammara-20,25-dien-3α-ol and a mixture of alkyl (24R*)-methyldammar-25-en-20-ol-3β-carboxylates, together with three previously described triterpenes: carnaubadiol, (24R*)-methyldammara-20,25-dien-3β-ol and (24R*)-24-methyldammara-20,25-dien-3-one. Moreover, four fatty alcohols (eicosanol, docosanol, tetracosanol and hexacosanol) as well as four sterols (cholesterol, campesterol, stigmasterol, and sitosterol) were also obtained. These compounds were isolated using classical chromatographic methods and their structures were determined by spectroscopic and chemical methods.
- De Almeida, Buana C.,Araújo, Bruno Q.,Barros, Elcio D. S.,Freitas, Samya D. L.,Maciel, Dayany S. A.,Ferreira, Ari J. S.,Guadagnin, Rafael C.,Vieira, Gerardo M.,Lago, Jo?o H. G.,Chaves, Mariana H.
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p. 1371 - 1376
(2017/07/13)
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- New lipoxygenase and cholinesterase inhibitory sphingolipids from Carthamus oxyacantha
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Two new sphingolipids: oxyacanthin A [(2S,3S,4R)-2-{[(2R,5E)-2-hydroxyoctadec-5-enoyl]amino}hexaeicosane-1,3,4-triol; 1] and B [(2S,3S,4R)-2-{[(2R,5E)-2-hydroxyoctadec-5-enoyl]amino}hexaeicosane-1,3,4-triol-1-O-β-D-glucopyranoside; 2], together with 1-octacosanol, β-sitosterol, β-sitosterol 3-O-β-D-glucopyranoside and luteolin 7-O-β-glucopyranoside were isolated from the methanolic extract of the whole plant of Carthamus oxyacantha. Their structures were elucidated using1H and13C NMR spectra and 2D NMR analyses (HMQC, HMBC and COSY) in combination with mass spectrometry (EI-MS, HR-EI-MS, FAB-MS and HR-FAB-MS) experiments and in comparison with the literature data of the related compounds. Both the compounds 1 and 2 showed inhibitory potential against lipoxygenase (LOX) in a concentration-dependent manner with IC50values 83.3?±?1.3 and 245.7?±?1.1?μM, whereas compound 2 showed inhibition against enzymes acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with IC50values 65.3?±?0.1 and 93.6?±?0.1?μM, respectively.
- Dilshad, Muhammad,Riaz, Naheed,Saleem, Muhammad,Shafiq, Nusrat,Ashraf, Muhammad,Ismail, Tayaba,Rafiq, Hafiza Mehwish,Jabbar, Abdul
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p. 1787 - 1795
(2016/08/16)
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- Identification and Synthesis of Branched Wax-type Esters, Novel Surface Lipids from the Spider Argyrodes?elevatus (Araneae: Theridiidae)
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The analysis of cuticular extracts from the kleptoparasitic spider Argyrodes?elevatus revealed the presence of unusual esters, new for arthropods. These novel compounds proved to be methyl-branched long-chain fatty acid esters with methyl branches located either close or remote from the internally located ester group. The GC/MS analysis of the prosoma lipid blend from the male cuticle contained one major component, undecyl 2-methyltridecanoate (1). In contrast, four major wax-type esters, 2-methylundecyl 2,8-dimethylundecanoate (2), 2,8-dimethylundecyl 2,8-dimethylundecanoate (3), heptadecyl 4-methylheptanoate (4), and 14-methylheptadecyl 4-methylheptanoate (5), were identified in the lipid blend of female prosomata. Structure assignments were based on mass spectra, gas chromatographic retention indices, and microderivatization. Unambiguous proof of postulated structures was ensured by an independent synthesis of all five esters. Preferentially, odd-numbered carbon chains pointed to a distinct biosynthetic pathway, different from that of common fatty acids, because one or two C3 starter units are incorporated during the biosynthesis of all acid and alcohol building blocks present in the five esters. The striking sexual dimorphism together with the unique biosynthesis points to a function of the esters in chemical communication of the spiders, although no behavioral data are currently available to test this assumption.
- Chinta, Satya Prabhakar,Goller, Stephan,Uhl, Gabriele,Schulz, Stefan
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p. 1202 - 1220
(2016/10/03)
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- Pd-Catalyzed Regioselective Alkoxycarbonylation of 1-Alkenes Using a Lewis Acid [SnCl2 or Ti(OiPr)4] and a Phosphine
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The phosphine ligand mediated palladium catalyzed alkoxycarbonylation of alkenes was investigated with the objective of attaining good linear selectivity for the ester. The effect of various parameters such as solvents, additives, palladium precursors, CO pressures, and alkenes of various structural complexities were examined. The results revealed the importance of using a Lewis acid such as SnCl2 or Ti(OiPr)4 in combination with a monodentate ligand such CYTOP 292 or P(p-anisyl)3 to enhance the regioselectivity for the linear isomers in the range of 70-96%.
- Amézquita-Valencia, Manuel,Achonduh, George,Alper, Howard
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p. 6419 - 6424
(2015/06/30)
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- Lewis Base Activation of Silyl Acetals: Iridium-Catalyzed Reductive Horner-Wadsworth-Emmons Olefination
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A Lewis base promoted deprotonative pronucleophile addition to silyl acetals has been developed and applied to the iridium-catalyzed reductive Horner-Wadsworth-Emmons (HWE) olefination of esters and the chemoselective reduction of the resulting enoates. Lewis base activation of silyl acetals generates putative pentacoordinate silicate acetals, which fragment into aldehydes, silanes, and alkoxides in situ. Subsequent deprotonative metalation of phosphonate esters followed by HWE with aldehydes furnishes enoates. This operationally convenient, mechanistically unique protocol converts the traditionally challenging aryl, alkenyl, and alkynyl esters to homologated enoates at room temperature within a single vessel.
- Dakarapu, Udaya Sree,Bokka, Apparao,Asgari, Parham,Trog, Gabriela,Hua, Yuanda,Nguyen, Hiep H.,Rahman, Nawal,Jeon, Junha
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supporting information
p. 5792 - 5795
(2015/12/11)
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- Cytotoxic ceramides from the Red Sea sponge Spheciospongia vagabunda
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Extracts of Egyptian marine organisms from the Red Sea were screened for their anticancer activity using sulforhodamine B assay. The extract of the Red Sea sponge Spheciospongia vagabunda possessed promising anticancer activity against HepG2 (liver cancer cell line) and MCF-7 (breast cancer cell line). Isolation of three new ceramides: N-[(2S,3S,4R)-1,3,4-trihydroxytetradecan-2-yl] tridecanamide (1), (R)-2′-hydroxy-N-[(2S,3S,4R)-1,3,4-trihydroxypentacosan-2-yl] octadecanamide (2) and (R,Z)-2′-hydroxy-N-[(2S,3S,4R)-1,3,4-trihydroxytricosan-2-yl) nonadec-10-enamide (3) was accomplished via bioassay-guided fractionation. Structure elucidation was achieved using spectroscopic techniques, including 1D and 2D NMR and HRMS. Compounds 2 and 3 displayed high potential cytotoxicity against HepG2 (IC50 24.7 and 21.3 μM, respectively) and MCF-7 (IC50 26.8 and 29.8 μM, respectively), compared with doxorubicin as control drug.
- Eltamany, Enas Elsayed,Ibrahim, Amany K.,Radwan, Mohamed M.,Elsohly, Mahmoud A.,Hassanean, Hashim A.,Ahmed, Safwat A.
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p. 3467 - 3473
(2015/08/03)
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- Metal/bromide autoxidation of triglycerides for the preparation of FAMES to improve the cold-flow characteristics of biodiesel
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Triglyceride autoxidation using a homogeneous Co/Mn/Zr/bromide catalyst in acetic acid (93%) of low grade tallow, canola oil or soy bean oil in a batch reactor at 150 °C for 2 h, produced lower molecular weight products relative to the fatty acids of the starting triglycerides. For the autoxidation of tallow the main products after esterification were monoesters Me(CH 2)mC(O)OMe (m = 5-12) and diesters MeOC(O)(CH 2)nC(O)OMe, (n = 7-12). Oxidation of the saturated fatty acids in triglycerides was confirmed and modelled using methyl palmitate. Post-treatment esterification of tallow autoxidation products to produce biodiesel (BD) esters resulted in improved cold temperature properties by a mean of 13.0 °C, i.e. a mean cloud point (CP) 1.0 °C (cf. unmodified tallow biodiesel: CP 14 °C).
- Phung, Peter,Rowlands, William N.,Thiyakesan, Appadurai,Benndorf, Paul,Masters, Anthony F.,Maschmeyer, Thomas
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p. 162 - 168
(2014/07/07)
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- Manufacture of C13 higher fatty acids from their esters by carbonylation of dodecene-1 in ionic liquid medium
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The effect of catalyst nature, temperature, acidity, promoters, and feedstock composition on dodecene-1 carbonylation in the presence of Pd compounds in an ionic liquid medium yielding higher fatty acid and their esters was studied. Palladium salts without phosphine ligands show high activity in tetrabutylammonium bromide. In systems of this kind, the catalyst is suspended in the reaction mass in the form of Pd particles with a size of 4-10 nm. It was shown that the catalytic system can be repeatedly used without loss of activity. It is acceptable to use synthesis gas instead of bare carbon monoxide with the selectivity for tride-canoic acid increasing.
- Lapidus,Eliseev,Bondarenko,Chau
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experimental part
p. 442 - 449
(2011/10/03)
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- DIRECT METHOD AND REAGENT KITS FOR FATTY ACID ESTER SYNTHESIS
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Provided are efficient, cost-effective and water tolerant methods (e.g., single-vial methods) for preparing fatty acid esters from organic matter, comprising: obtaining organic matter comprising at least one fat substituent, contacting the organic matter in a reaction mixture with a basic solution under conditions suitable to provide for hydrolytic release of monomeric fatty acids from the at least one fat substituent to provide a base-treated reaction mixture, and esterifying the monomeric fatty acids of the base-treated reaction mixture by acidification of the reaction mixture and treating in the presence of an organic alcohol to provide fatty acid esters. The methods optionally further comprise, prior to esterifying, neutralizing the base-treated reaction mixture to provide for neutralized fatty acids, separating the neutralized fatty acids from the neutralized reaction mixture, and dissolving the separated fatty acids in the esterification reaction mixture. Also provided are related methods and kits for fat analysis.
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Page/Page column 18; 23-24; Sheet 1/5
(2008/12/07)
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- Radical cyanocarbonylation using alkyl allyl sulfone precursors
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Acyl cyanides have been prepared by the three-component coupling reactions comprised of alkyl allyl sulfones, carbon monoxide, and p-tolylsulfonyl cyanide under tin-free radical reaction conditions. Georg Thieme Verlag Stuttgart.
- Kim, Sangmo,Cho, Chang Ho,Kim, Sunggak,Uenoyama, Yoshitaka,Ryu, Ilhyong
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p. 3160 - 3162
(2007/10/03)
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- Facile oxidative conversion of alcohols to esters using molecular iodine
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A simple, efficient, and high-yield procedure for the oxidative conversion of alcohols to various types of esters and ketones, with molecular iodine and potassium carbonate was successfully carried out.
- Mori, Naoshi,Togo, Hideo
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p. 5915 - 5925
(2007/10/03)
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- Highly selective formation of linear esters from terminal and internal alkenes catalysed by palladium complexes of bis-(di-tert-butylphosphinomethyl) benzene
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The methoxycarbonylation of terminal or internal alkenes catalysed by palladium complexes of bis-(di-tert-butylphosphinomethyl)benzene under mild conditions leads to linear esters in 99% selectivity via a hydride mechanism.
- Rodriguez, Cristina Jimenez,Foster, Douglas F.,Eastham, Graham R.,Cole-Hamilton, David J.
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p. 1720 - 1721
(2007/10/03)
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- A Novel, Chemoselective, "One-pot" Procedure for the Simultaneous Denitration-Deoxygenation of 2-Nitroketones by TsNHNH2-NaBH4
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Chemoselective conversion of both the carbonyl group and the carbon bearing the nitro group, of 2-nitro ketones, into two methylenes is performed in one-pot, under mild conditions.
- Ballini, Roberto,Castagnani, Roberto,Marcantoni, Enrico
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p. 3161 - 3162
(2007/10/02)
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- Selective Mono- and Bis(alkoxycarbonylation)s of Olefins Catalyzed by Palladium in the Presence of Cu(I) or Cu(II) Chloride under Remarkably Mild Conditions. Application to the Synthesis of γ-Butyrolactone Derivatives
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Palladium-catalyzed mono- and bis(alkoxycarbonylation)s of the olefins were controlled by the use of copper(II) and copper(I) chloride, respectively, in alcohol under normal pressure of carbon monoxide and oxygen at room temperature without any other additives. 3-Buten-1-ols gave the corresponding γ-butyrolactones and 2-oxotetrahydrofuran-3-acetic acid esters, respectively, in high yields.
- Toda, Shiho,Miyamoto, Masanori,Kinoshita, Hideki,Inomata, Katsuhiko
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p. 3600 - 3606
(2007/10/02)
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- New one carbon homologation reagents utilizing electrochemical oxidation of organosilicon compounds
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Phenylthio(trimethylsilyl)methane, phenylthiobis(trimethylsilyl)methane, methoxy(trimethylsilyl)-methane, and methoxybis(trimethylsilyl)methane are deprotonated and the resulting anions are alkylated with electrophiles such as organic halides. The alkylation products are readily converted into the corresponding dimethyl acetals or methyl esters by electrochemical oxidation in methanol.
- Yoshida,Matsunaga,Murata,Isoe
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p. 615 - 624
(2007/10/02)
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- Selective Mono- and Dicarbonylation of Terminal Olefins Catalyzed by Pd-C in the Presence of Cu(II) or Cu(I) Chloride under Mild Conditions
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Pd-C can catalyze the carbonylation of terminal olefins with normal pressure of carbon monoxide at room temperature.The corresponding mono- and diesters (succinates) were selectively formed in excellent yields using Cu(II) and Cu(I) chloride, respectively, in alcohol.
- Inomata, Katsuhiko,Toda, Shiho,Kinoshita, Hideki
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p. 1567 - 1570
(2007/10/02)
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- Alkyl isocyanides as precursors for the formation of carbon-carbon bonds
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Tris(trimethylsilyl)silane is an effective mediator for the formation of carbon-carbon bonds via radicals using alkyl isocyanides as precursors.
- Chatgilialoglu,Giese,Kopping
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p. 6013 - 6016
(2007/10/02)
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- METHOXY(TRIMETHYLSILYL)METHANE AND METHOXYBIS(TRIMETHYLSILYL)METHANE AS NEW REAGENTS FOR HOMOLOGATION
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New synthons of formyl anion methoxy(trimethylsilyl)methane (1)) and alkoxycarbonyl anion (methoxybis(trimethylsilyl)methane (2)) have been developed using oxidative cleavage of the carbon-silicon bond by anodic oxidation.
- Yoshida, Jun-ichi,Matsunaga, Shin-ichiro,Isoe, Sachihiko
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p. 219 - 222
(2007/10/02)
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- Palladium(II) Chloride Catalyzed Carbonylation of Organic Tellurides with Carbon Monoxide
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Various organic tellurides react with carbon monoxide (1 atm) at room temperature in methanol in the presence of PdCl2 and Et3N to afford the corresponding methyl carboxylates in good to excellent yields.The reaction is catalytic in PdCl2 when a suitable reoxidant such as CuCl2, CuCl/O2, FeCl3 or Ce(NH4)2(NO3)6 is present.The combination of this carbonylation with phenyltellurenylation of arylacetylenes and propargylic alcohols makes it possible to prepare ring-substituted cis-methyl cinnamates and Δα,β-butenolides, respectively.Both monomeric and dimeric palladium complexes, (Ph2Te)2PdCl2 and 2, react readily with CO to give a high yield of methyl benzoate.The key step of the present carbonylation is proposed to be the migration of an organic moiety from Te to Pd (transmetalation) in organic telluride-PdCl2 complexes, presumably formed in situ, to afford organopalladium compounds.
- Ohe, Kouichi,Takahashi, Hidetaka,Uemura, Sakae,Sugita, Nobuyuki
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p. 4859 - 4863
(2007/10/02)
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- Electrochemical Oxidation of 1-Phenylthio-1-trimethylsilylalkanes
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Electrochemical oxidation of 1-phenylthio-1-trimethylsilylalkanes in the presence of alcohol resulted in facile cleavage of the carbon-silicon bond and formation of the corresponding acetals.
- Yoshida, Jun-ichi,Isoe, Sachihiko
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p. 631 - 634
(2007/10/02)
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- Carbonylation of Organomercury Compounds: A General Synthesis of Carboxylic Acids and Esters
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Organomercury compounds react with carbon monoxide in aqueous or alcoholic media to give good yields of carboxylic acids or esters.The carboxyl group is introduced selectively at the site of the carbon-mercury bond.Homogeneous group 9 and 10 metal complexes catalyze this carbonylation reaction, which yields mercury(0) as the inorganic byproduct.The mercuration-carbonylation sequence represents a general synthesis of carboxylic acids and esters.
- Baird, William C.,Hartgerink, Ronald L.,Surridge, John H.
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p. 4601 - 4605
(2007/10/02)
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- SELECTIVE MIXED COUPLING OF CARBOXYLIC ACIDS (II). -PHOTOLYSIS OF UNSYMMETRICAL DIACYLPEROXIDES WITH ALKENYL-, HALO-, KETO-, CARBOXYL-GROUPS AND A CHIRAL α-CARBON. COMPARISON WITH THE MIXED KOLBE ELECTROLYSIS.
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- Alkenoyl and functionalized alkanoyl dodecanoyl peroxides are prepared in 70 to 97 percent yield and photolyzed at -78 deg C.Thereby 4- to 10-alkenoyl and 4-alkynoyl peroxides afford good yields (56 - 68 percent) of unsymmetrical coupling products.Similarly α- to δ-haloalkanoyl, cholanoyl or 3- and 4-carboxyalkanoyl peroxides can be coupled (40 - 70 percent).The α-chiral diacyl peroxide 1s undergoes the photochemical coupling reaction with 80 percent retention of its configuration.The photolysis of diacyl peroxides at -78 deg C proves to be a favorable supplement of the Kolbe-electrolysis in cases, where the electrolysis fails or produces low yields.
- Feldhues, Michael,Schaefer, Hans J.
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p. 4213 - 4236
(2007/10/02)
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- UTILIZATION OF METHYLTHIOMETHYL p-TOLYL SULFONE IN ORGANIC SYNTHESIS
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Methylthiomethyl p-tolyl sulfone was found to be one of the useful reagents for preparation of various organic compounds such as S-methyl α-ketocarbothioates, carboxylic esters, five- and six-membered cycloalkanones, and α-methoxy-α-arylacetic esters.
- Ogura, Katsuyuki,Yahata, Nobuhiro,Hashizume, Kimitoshi,Tsuyama, Koichi,Takahashi, Kazumasa,Iida, Hirotada
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p. 767 - 770
(2007/10/02)
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- SYNTHESIS OF CARBOXYLIC ESTERS USING FORMALDEHYDE DIMETHYL DITHIOACETAL S,S-DIOXIDE
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Formaldehyde dimethyl dithioacetal S,S-dioxide (1) reacted with an alkyl bromide or a 2-alkenyl bromide (8) under phase-transfer conditions using 50percent aq.NaOH to give an alkyl or 2-alkenyl derivative of 1, whereas, in the reaction with 8 in the presence of K2CO3-KI in HMPA, 1 formed a 1-alken-3-yl derivative.Transformation of these products into the corresponding carboxylic esters was also described.
- Ogura, Katsuyuki,Watanabe, Jun-ichi,Iida, Hirotada
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p. 4499 - 4502
(2007/10/02)
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- Mode of Metabolism of 1-Tetradecene by Candida Yeasts and Citrates Production
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Metabolic pathways for the oxidation of 1-tetradecene by Candida lipolytica were investigated and compared with those for Candida tropicalis in oder to elucidate the difference in the productivity of citrates reported in the previous paper.No difference was found in the pathways for the initial stage of oxidation of 1-tetradecene between the two strains, indicating that the difference in the productivity of citrates is not attributable to the metabolic pathways.The metabolic rate of 1-tetradecene with C. lipolytica was found to be much lower than that with C. tropicalis.The production of citrates was much enhanced in the presence of surfactants which were known to be stimulative for microbial metabolism of hydrocarbons and 11-15 g/liters was attained on the 6th day of cultivation.
- Terasawa, Masato,Takahashi, Joji
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p. 2433 - 2442
(2007/10/02)
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