Showing papers in "Chemistry Letters in 1983"
TL;DR: Fluoride-induced 1,2-elimination of o-trimethylsilylphenyl triflate provided a convenient route to benzyne under mild conditions where detriflation from an intermediary aryl anion appeared to occur in preference to protonation even in the presence of alcohols as discussed by the authors.
Abstract: Fluoride-induced 1,2-elimination of o-trimethylsilylphenyl triflate provided a convenient route to benzyne under mild conditions where detriflation from an intermediary aryl anion appeared to occur in preference to protonation even in the presence of alcohols.
748 citations
TL;DR: In this article, the reaction of N,N-diethylamino-tributyltin with aryl bromides in the presence of a catalytic amount of PdCl2(o-tolyl3P)2 gave N, N-deterministic derivatives, a new kind of amination different from ones through aryne or SRN1 mechanise
Abstract: The reaction of N,N-diethylamino-tributyltin with aryl bromides in the presence of a catalytic amount of PdCl2(o-tolyl3P)2 gave N,N-diethylaminobenzene derivatives. The reaction is a new kind of amination different from ones through aryne or SRN1 mechanise
263 citations
TL;DR: In this paper, the 1,2- and 1,3-glycols are easily cleft by diisobutylaluminum hydride in a toluene solution at 0 °C-room temperature to give the corresponding monobenzyl ethers of the glycols.
Abstract: Benzylidene acetals of 1,2- and 1,3-glycols are easily cleft by diisobutylaluminum hydride in a toluene solution at 0 °C–room temperature to give the corresponding monobenzyl ethers of the glycols. In general the reaction proceeds excellently in regioselective manner depending on the stereochemical environment.
147 citations
TL;DR: Silyl enol ethers are converted to 2-allyl ketones and aldehydes by the reaction with allylic carbonates in the presence of a palladium-phosphine catalyst.
Abstract: Silyl enol ethers are converted to 2-allyl ketones and aldehydes by the reaction with allylic carbonates in the presence of a palladium-phosphine catalyst.
82 citations
TL;DR: In this article, 1,2-cis-Ribofuranosides are synthesized in high yields by the reaction of β-ribofuranoyl fluoride and alcohols in the presence of stannous chloride and trityl perchlorate.
Abstract: 1,2-cis-Ribofuranosides are stereoselectively synthesized in high yields by the reaction of β-ribofuranosyl fluoride and alcohols in the presence of stannous chloride and trityl perchlorate. Under similar condition, α-arabinofuranosyl fluoride reacts with cholestanol to give 1,2-cis-arabinofuranoside predominatly.
70 citations
TL;DR: In this article, a stable colloidal dispersion of copper in water is prepared by the reduction of copper sulfate with sodium tetrahydroborate in the presence of poly(vinylpyrrolidone), poly (vinyl alcohol), dextrin, or poly(methyl vinyl ether).
Abstract: Stable colloidal dispersion of copper in water is prepared by the reduction of copper sulfate with sodium tetrahydroborate in the presence of poly(vinylpyrrolidone), poly(vinyl alcohol), dextrin, or poly(methyl vinyl ether). The poly(vinylpyrrolidone)-protected copper colloids are effective for the selective catalysis in hydration of acrylonitrile to acrylamide at 80°C in water.
69 citations
TL;DR: In this paper, the reaction of diethylzinc with arylaldehydes catalyzed by Co(α-cqdH)2 and Pd(β-αqdh)2 in toluene at room temperature gave optically active alcohols almost quantitatively in 40-60% ee.
Abstract: The reaction of diethylzinc with arylaldehydes catalyzed by Co(α-cqdH)2 and Pd(α-cqdH)2 in toluene at room temperature gave optically active alcohols almost quantitatively in 40–60% ee.
67 citations
TL;DR: The polymer films, prepared by the electrochemical polymerization of aniline and its derivatives, were electroactive in an acidic solution and were possessed of the selectivity for the redox reaction of species in solution as discussed by the authors.
Abstract: The polymer films, prepared by the electrochemical polymerization of aniline and its derivatives, were electroactive in an acidic solution. Electrodes coated with these films were possessed of the selectivity for the redox reaction of species in solution.
67 citations
TL;DR: Several metallophthalocyanines were obtained by heating phthalonitrile with metal salts in alcohols in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene.
Abstract: Several metallophthalocyanines (MPc: M=Ni(II), Co(II), Zn(II), Pb(II), Fe(II), Sn(II), Cd(II), Mg(II), and Mn(III)) were obtained by heating phthalonitrile with metal salts in alcohols in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene. Metal acetylacetonates as well as metal halides were available as metal sources for preparation of metallophthalocyanines by this method.
66 citations
TL;DR: In this article, the boron trioxide coupled with hydroxyapatite was found to catalyze the Beckmann rearrangement of cyclohexanone oxime in the vapor phase at 300 °C more selectively than boria-alumina and silica alumina.
Abstract: The boron trioxide coupled with hydroxyapatite was found to catalyze the Beckmann rearrangement of cyclohexanone oxime in the vapor phase at 300 °C more selectively than boria-alumina and silica-alumina. The basic property of hydroxyapatite appears to play an important role in effecting the rearrangement selectively.
65 citations
TL;DR: In this article, the synthesis of ammonia from N2 and H2O and its photodecomposition over SrTiO3 and BaTiOO3 based catalysts were investigated.
Abstract: Photocatalytic synthesis of ammonia from N2 and H2O and its photodecomposition were investigated over SrTiO3 and BaTiO3 based catalysts. It was demonstrated that the yield of NH3 formation increased markedly by the use of RuO2 and NiO doped three component catalysts and that photodecomposition of NH3 was coupled with photodecomposition of H2O.
TL;DR: O-(5-O-Feruloyl-α-L-arabinofuranosyl)-(1→3)-O-β-D-xylopyranosyl-(1→4)-D-Xyopyranose (I) was isolated from the enzymatic hydrolysate of bagasse lignin-carbohydrate complex containing ferulic acid (LCC-F) and identified from I.R. spectra as mentioned in this paper.
Abstract: O-(5-O-Feruloyl-α-L-arabinofuranosyl)-(1→3)-O-β-D-xylopyranosyl-(1→4)-D-xylopyranose (I) was isolated from the enzymatic hydrolysate of bagasse lignin–carbohydrate complex containing ferulic acid (LCC-F) and identified from I.R., U.V., G.L.C.-M.S., and N.M.R. spectra.
TL;DR: Vitamin C showed a synergistic effect when used with vitamin E and acted as a radical scavenger and suppress the oxidation of methyl linoleate in homogeneous alcohol solution in the presence of radical initiator.
Abstract: Ascorbic acid (vitamin C) was found to act as a radical scavenger and suppress the oxidation of methyl linoleate in homogeneous alcohol solution in the presence of radical initiator. Furthermore, vitamin C showed a synergistic effect when used with vitamin E.
TL;DR: In the crystal of β-(BEDT-TTF)2PF6, BEDT TTF (bis(ethylenedithiolo)tetrathiafulvalene) molecules are arranged side-by-side.
Abstract: In the crystal of β-(BEDT-TTF)2PF6, BEDT-TTF (bis(ethylenedithiolo)tetrathiafulvalene) molecules are arranged side-by-side. The anisotropy of the electrical resistivity shows that β-(BEDT-TTF)2PF6 is the first organic conductor where the conductivity is the largest along the direction parallel to the molecular plane. The metal-insulator transition is observed at 297 K. The thermoelectric power corresponds to that due to the hole conduction in highly correlated system.
TL;DR: In this paper, the relative efficiencies of different sources of F− in catalysing the Michael reaction of nitroethane to 3-buten-2-one were investigated.
Abstract: A study of the relative efficiencies of different sources of F− in catalysing the Michael reaction of nitroethane to 3-buten-2-one reveals that KF or CsF supported on alumina are the best reagents.
TL;DR: Cast films were prepared on glass from aqueous dispersions of double-chain ammonium amphiphiles and specific spectral variations were observed for film-bound cyanine and merocyanine dyes as mentioned in this paper.
Abstract: Cast films were prepared on glass from aqueous dispersions of double-chain ammonium amphiphiles. The bilayer characteristics were preserved and specific spectral variations were observed for film-bound cyanine and merocyanine dyes.
TL;DR: In this paper, the N-(p-Methoxybenzyl) groups in some diketopiperazine derivatives were removed with ceric ammonium nitrate in acetonitrile-water under mild conditions, where N-benzinyl, methoxyl in the aminal structure, and isolated vinyl groups remained unchanged.
Abstract: N-(p-Methoxybenzyl) groups in some diketopiperazine derivatives were proved to be readily and efficiently removed with ceric ammonium nitrate in acetonitrile-water under mild conditions, where N-benzyl , methoxyl in the aminal structure, and isolated vinyl groups remained unchanged.
TL;DR: In this paper, a cross-conjugated triene, 3-benzylidene-2,4-bis(trimethylsilyloxy)-1, 4-pentadiene, was synthesized and the multiple Diels-Alder cycloaddition reactions to acetylenic dienophiles leading to the dihydronaphthols were demonstrated.
Abstract: A novel cross-conjugated triene, 3-benzylidene-2,4-bis(trimethylsilyloxy)-1,4-pentadiene, was synthesized and the multiple Diels–Alder cycloaddition reactions to acetylenic dienophiles leading to the dihydronaphthols were demonstrated.
TL;DR: In this article, it has been demonstrated that oxidation reactions of organic compounds over H3PMo12O40 and its alkali salts are classified into two prototypes: surface redox properties of catalysts and the bulk properties.
Abstract: It has been demonstrated that oxidation reactions of organic compounds over H3PMo12O40 and its alkali salts are classified into two prototypes. In the first type reactions, the surface redox properties of catalysts are important, and in the second type the bulk properties. Oxygen-addition reactions like methacrolein to methacrylic acid are an example of the former, and oxidative dehydrogenation is the latter example.
TL;DR: Eosin Y was not photobleached with triethanolamine (TEOA) on visible light irradiation in the presence of methyl viologen (Mv2+), and worked as an effective sensitizer to reduce Mv2+, into MV+· with TEOA in aqueous ethanol as mentioned in this paper.
Abstract: Eosin Y was not photobleached with triethanolamine (TEOA) on visible light irradiation in the presence of methyl viologen (Mv2+), and worked as an effective sensitizer to reduce Mv2+ into MV+· with TEOA in aqueous ethanol. The resulting MV+· reduced water to hydrogen in the presence of colloidal platinum in the same solvent. The quantum yield for MV+· formation was measured to be ca. 0.3.
TL;DR: Oppositane-, eudesmane-, and new cycloeudesmene-type sesquiterpenes were isolated from Torilis japonica D.C. as discussed by the authors.
Abstract: Oppositane-, eudesmane-, and new cycloeudesmane-type sesquiterpenes were isolated from Torilis japonica D.C. All the compounds can be biogenetically correlated to epoxygermacrene-D.
TL;DR: Kumausallene, a new C15-bromoallene has been isolated from the title alga, and its structure was established on the basis of the spectral properties and chemical degradation as discussed by the authors.
Abstract: Kumausallene, a new C15-bromoallene has been isolated from the title alga, and its structure was established on the basis of the spectral properties and chemical degradation.
TL;DR: In this article, a cyclic mechanism for the WGSR was proposed to proceed via [Ru(bpy)2(CO)2]2+, [Ru[bpy]2 (CO) (COOH)]+, and [Ru((bpy)-2,2′-bipyridine)) as intermediates successively.
Abstract: A new preparative method of [Ru(bpy)2 (CO)Cl]+ (bpy=2,2′-bipyridine) and the water gas shift reaction (WGSR) catalyzed by this complex are described. A cyclic mechanism for the WGSR is proposed to proceed via [Ru(bpy)2(CO)2]2+, [Ru(bpy)2(CO) (COOH)]+, and [Ru(bpy)2(CO)H]+ as intermediates successively; the former two were isolated.
TL;DR: In this article, a binuclear copper(II) complex bridged by an alkoxo-oxygen atom and an acetate ion was prepared, and its crystal structure was determined by X-ray diffraction method.
Abstract: New binuclear copper(II) complex bridged by an alkoxo-oxygen atom and an acetate ion was prepared, and its crystal structure was determined by X-ray diffraction method.
TL;DR: In this article, the β- and activated materials were found to be the most efficient and specific redox catalysts, and a 230% of O2 yield was obtained based on MnO2.
Abstract: Catalytic formation of oxygen from water was observed in the photosensitized reaction by trisbipyridineruthenium(II) using manganese dioxide as a redox catalyst and pentaammine chlorocobalt(III) as an electron acceptor in acidic solution. The β- and “activated” materials are found to be the most efficient and specific redox catalysts, and a 230% of O2 yield based on MnO2 is obtained.
TL;DR: Metallic manganese is found to reduce allylic bromides and achieve the Barbier-type carbonyl addition of allyl unit as mentioned in this paper. But it is not suitable for the use of inorganic compounds.
Abstract: Metallic manganese is found to reduce allylic bromides and achieve the Barbier-type carbonyl addition of allyl unit
TL;DR: Azobenzene-bridged crown ether in the ternary composite membrane exhibits trans–cis photoisomerization by irradiation of ultraviolet and visible lights and the cation permeation is remarkably influenced by the magnitude of solubility of counter-anion to the composite membrane.
Abstract: Azobenzene-bridged crown ether(AZO-CR) in the ternary composite membrane exhibits trans–cis photoisomerization by irradiation of ultraviolet and visible lights. The K+ ion permeation through the ternary composite membrane is facilitated by photoirradiation. The facilitated transport of K+ ion is in strong relation to an altered affinity of AZO-CR for K+ ion due to the trans–cis configurational change of AZO-CR induced by photoirradiation. The cation permeation is remarkably influenced by the magnitude of solubility of counter-anion to the composite membrane.
TL;DR: In this article, the crystal of α-(BEDT-TTF)2PF6 belongs to triclinic system and is a semiconductor with a small band gap of about 0.1 eV.
Abstract: The crystal of α-(BEDT-TTF)2PF6 belongs to triclinic system (BEDT-TTF: bis(ethylenedithiolo)-tetrathiafulvalene). The close intermolecular contacts along the c axis suggests the strong tendency for the side-by-side arrangement of BEDT-TTF molecules. The electrical resistivity measurements show that α-(BEDT-TTF)2PF6 is a semiconductor with a small band gap of about 0.1 eV.
TL;DR: In this paper, four new halogenated C15-nonterpenoids which are unusual oxolane derivatives have been isolated from the red alga L. nipponica Yamada, and their structures were determined by spectral and chemical evidence.
Abstract: Four new halogenated C15-nonterpenoids which are unusual oxolane derivatives have been isolated from the red alga L. nipponica Yamada, and their structures were determined by spectral and chemical evidence.
TL;DR: In this paper, it was shown that methyl formate from formaldehyde was enhanced by the presence of methanol over copper-silica and support-free copper catalysts.
Abstract: Formation of methyl formate from formaldehyde was markedly enhanced by the presence of methanol over copper-silica and support-free copper catalysts It was revealed that in the presence of methano