Showing papers on "Benzaldehyde published in 1989"
TL;DR: La reaction d'allyl-2 diphenyl-4,5 ditosyl-1,3)diazaborolidines 1,3,2 chirales avec des aldehydes fournit des alcools homoallyliques de maniere enantioselective as discussed by the authors
Abstract: La reaction d'(allyl-2 diphenyl-4,5 ditosyl-1,3)diazaborolidines-1,3,2 chirales avec des aldehydes fournit des alcools homoallyliques de maniere enantioselective
232 citations
TL;DR: The addition of diethylzinc-orthotitanate complex to benzaldehyde catalyzed by 0.0001∼0.04 equiv of chiral sulfonamide-titanate in toluene at 0∼ −30° gives optically active 1-phenylpropanol in both high ee and chemical yields as discussed by the authors.
184 citations
TL;DR: In this article, the aromatic ring-retaining products formed from the gas phase reactions of the OH radical with benzene and toluene, in the presence of NOx, have been identified and their formation yields determined.
Abstract: The aromatic ring-retaining products formed from the gas–phase reactions of the OH radical with benzene and toluene, in the presence of NOx, have been identified and their formation yields determined. These products, and their formation yields, are as follows: from benzene – phenol, 0.236 ± 0.044; nitrobenzene, {(0.0336 ± 0.0078) + (3.07 ± 0.92) × 10−16[NO2]}; from toluene – benzaldehyde, 0.0645 ± 0.0080; benzyl nitrate, 0.0084 ± 0.0017; o−cresol, 0.204 ± 0.027; m− + p−cresol, 0.048 ± 0.009; m-nitrotoluene, {(0.0135 ± 0.0029) + (1.90 ± 0.25) × 10−16[NO2]}, where the NO2 concentration is in molecule cm−3 units. The formation yields of o- and p-nitrotoluene from toluene were ca. 0.07 and 0.35 that of m-nitrotoluene, respectively. The observations that the nitro-aromatic yields do not extrapolate to zero as the NO2 concentration approaches zero are not consistent with current chemical mechanisms for these OH radical-initiated reactions, and suggest that under the experimental conditions employed in this study the hydroxycyclohexadienyl radicals formed from OH radical addition to the aromatic ring react with NO2 rather than with O2. However, these data concerning the nitroaromatic yields are consistent with our previous conclusions that many of the nitrated polycyclic aromatic hydrocarbons present in ambient air are formed, at least in part, in the atmosphere from OH radical reactions.
150 citations
109 citations
TL;DR: Benzaldehyde lyase was purified 70-fold and found to require catalytic amounts of thiamine PPi (TPP) and a divalent cation as cofactors and a catalytic mechanism for the enzyme is proposed.
Abstract: Pseudomonas fluorescens biovar I can grow on benzoin as the sole carbon and energy source. This ability is due to benzaldehyde lyase, a new type of enzyme that irreversibly cleaves the acyloin linkage of benzoin, producing two molecules of benzaldehyde. Benzaldehyde lyase was purified 70-fold and found to require catalytic amounts of thiamine PPi (TPP) and a divalent cation as cofactors. Optimal activity was obtained with a 1.0 mM concentration of Mn2+, Mg2+, or Ca2+. Gel permeation chromatography indicated a native molecular weight of 80,000, whereas the enzyme migrated in sodium dodecyl sulfate-containing polyacrylamide gels as a single polypeptide with a molecular weight of 53,000. Benzaldehyde lyase is highly specific; of a variety of structurally related compounds tested, only benzoin and anisoin (4,4'-dimethoxybenzoin) acted as substrates, their apparent Kms being 9.0 x 10(-3) and 3.25 x 10(-2) mM, respectively. A catalytic mechanism for the enzyme is proposed.
104 citations
TL;DR: In this article, reactions d'aldolisation de l'enolate de titane de la (t.butyldimethylsiloxy-1 cyclohexyl-1) butanone-2 chirale avec des aldehydes
Abstract: Reactions d'aldolisation de l'enolate de titane de la («t»-butyldimethylsiloxy-1 cyclohexyl-1)butanone-2 chirale avec des aldehydes
79 citations
TL;DR: In this article, it was shown that irradiation of solid β-cyclodextrin complexes of benzaldehyde produces optically active benzoin as a major photo-product with an enantiomeric excess of up to 15%.
70 citations
TL;DR: Indium(I) iodide was found to mediate in the Barbier allylation and in the Reformatsky reaction of aldehydes and ketones to give homoallylic alcohols and β-hydroxy esters, respectively, presumably via allylindium(III) diiodide as discussed by the authors.
68 citations
TL;DR: In this article, a meso-tetraphenylporphyrin monoaldehyde, 1c, was obtained from 1c and pyrrole in refluxing propionic acid.
63 citations
TL;DR: Purified alcohol oxidase was shown to function in a number of 2‐phase reaction systems of varied aqueous to organic phase ratios and could be firmly immobilized on DEAE‐Biogel (Biorad) to enhance stability and biocatalyst recovery.
Abstract: The low substrate specificity of alcohol oxidase from Pichia pastoris makes this enzyme system of potential biotechnological interest. Whole cells of Pichia pastoris are able to oxidize benzyl alcohol to benzaldehyde in aqueous reaction media. The low water solubility of the reactant and product of this bioconversion, combined with the ability of both to strongly inhibit the reaction, favor the use of nonaqueous reaction fluids. Purified alcohol oxidase was shown to function in a number of 2-phase reaction systems of varied aqueous to organic phase ratios (0.01-0.05 v/v). The apparent V(max) and K(m) were 5.26 g/Lh and 7.41 g/L respectively, for the oxidation of benzyl alcohol to benzaldehyde in hexane containing 3% aqueous phase. The volume of the aqueous phase had a strong effect on the reaction, with an aqueous: organic ratio of 3-5% found to be optimum. The enzyme could be firmly immobilized on DEAE-Biogel (Biorad) to enhance stability and biocatalyst recovery.
63 citations
TL;DR: Synthese de phenyl-6 (ou alkyl-6) dimethyl-3,4 tellurinne et de derives de telluro-2 bicyclo[2.2.1] as discussed by the authors.
Abstract: Synthese de phenyl-6 (ou alkyl-6) dimethyl-3,4 tellurinne et de derives de telluro-2 bicyclo[2.2.1] heptene-5 a partir de benzaldehyde (ou alcanal ou adamantanone-2 ou norcaranone-7) et d'un complexe (Me 2 Al) 2 Te
TL;DR: In this paper, the hetero Diels-Alder reaction between benzaldehyde and a functionalized diene can be catalyzed by the Lewis acid transition metal complexes, [CpRuLL′(CH2 CH2)]PF6 (L L′ PPh3, or LL′ = 1,2-bis-diphenylphosphinoethane, (−)-DIOP or (S,S)-CHIRAPHOS).
TL;DR: The dippp 2Pd is an efficient, unique catalyst for direct formylation of aryl chlorides to aldehydes with CO and sodium formate as mentioned in this paper.
Abstract: The complex (dippp)2Pd [dippp = 1,3-bis(di-isopropylphosphino)propane] is an efficient, unique catalyst for direct formylation of aryl chlorides to aldehydes with CO and sodium formate.
TL;DR: A wide spectrum of Z-1-iodo-alkenes is available by Wittig reaction of iodomethylene-triphenylphosphorane with aldehydes as mentioned in this paper.
TL;DR: In this paper, air-stable Mo(NO) (Cl) (π-crotyl) complexes add to aldehydes in the presence of methanol to yield homoallylic alcohols with high regiose-lectivity and diastereoselectivity.
TL;DR: Condensation of appropriately substituted benzaldehydes with either bis-Wittig reagents or bis-phosphonate esters (Homer-Emmons-Wadsworth modifications) containing one or two double bond units are general and quite efficient preparations of functionalized α,ω-diphenyl-polyenes containing 3, 4, 5, or 6 conjugated double bonds having all-E configurations as mentioned in this paper.
Abstract: Condensation of appropriately substituted benzaldehydes or cmnnamaldehydes with either bis-Wittig reagents or bis-phosphonate esters (Homer-Emmons-Wadsworth modifications) containing one or two double bond units are general and quite efficient preparations of functionalized α,ω-diphenyl-polyenes containing 3, 4, 5, or 6 conjugated double bonds having all-E configurations. Bis-Wittig reagents prepared from tributyl rather than the more normally utilized triphenylphosphine are much more reactive, particularly for bis-condensations in which the benzaldehyde or cinnamaldehyde is substituted with electron-donating groups.
TL;DR: The enantioselective aldol reactions of ketone lithium enolates with aldehydes mediated chiral lithium amides were extensively investigated in this paper, where the chiral amino ethers 4a, 4l and diamines 16a, b were prepared from α-amino acids.
TL;DR: o-Tolualdehyde and 1-chlorobenzaldehyde were poor substrates for aromatic carbinol formation although the latter produced significant aromatic alcohol in sucrose-containing media.
Abstract: The rate of production ofl-phenylacetyl carbinol bySaccharomyces cerevisiae in reaction mixtures containing benzaldehyde with sucrose or pyruvate as cosubstrate was investigated in short 1 h incubations. The effect of yeast dose rate, sucrose and benzaldehyde concentration and pH on the rate of reaction was determined. Maximum biotransformation rates were obtained with concentrations of benzaldehyde, sucrose and yeast of 6 g, 40 g and 60 g/l, respectively. Negligible biotransformation rates were observed at a concentration of 8 g/l benzaldehyde. The reaction had a pH optimum of 4.0–4.5. Rates of bioconversion of benzaldehyde and selected substituted aromatic aldehydes using both sucrose and sodium pyruvate as cosubstrate were compared. The rate of aromatic alcohol production was much higher when sucrose was used rather than pyruvate.o-Tolualdehyde and 1-chlorobenzaldehyde were poor substrates for aromatic carbinol formation although the latter produced significant aromatic alcohol in sucrose-containing media. Yields of 2.74 and 3.80 g/l phenylacetyl carbinol were produced from sucrose and pyruvate, respectively, in a 1 h reaction period.
TL;DR: The reversible isomerization of 5-hydrazino-1,2,3-thiadiazoles and 1-amino-5-mercapto-1 2, 3-triazoles has been established for an ester function at the 4 position (4a ⇌ 5a) as mentioned in this paper.
TL;DR: In this article, an examination of the reactions of tetrahydroquinoline, benzylamine and bibenzyl with supercritical water was made since water has been found to be effective as the solvent in the supercritical fluid extraction of coal.
TL;DR: In this paper, the configurations of these products were established by correlation with pseudoephedrine, and the configurations were assigned to (2R, 4S)-and (2S)-pentan-2-ol and (3R,4S)-4-hydroxy-3-methyl-(Z)-1,2-enol ethers, respectively.
Abstract: (1R)- and (1S)-1-[(–)-Menthyloxymethoxy]-(E)-but-2-enyl(tributyl)stannanes (8) and (9), whose configurations were assigned by correlation with (2R)- and (2S)-pentan-2-ol (14) and (15), react stereoselectively on heating with benzaldehyde to give (3S,4S)- and (3R,4R)-4-hydroxy-3-methyl-(Z)-1,2-enol ethers (16) and (18), respectively, the configurations of these products being established by correlation with pseudoephedrine.
Journal Article•
TL;DR: Triphenylphosphine reacts with 2-(2-azidoethoxy)benzaldehyde in an aza-Wittig reaction to give the unsaturated 14-membered trans-N 2 O 2 diimine macrocycle as mentioned in this paper.
Abstract: Triphenylphosphine reacts with 2-(2-azidoethoxy)benzaldehyde in an aza-Wittig reaction to give the unsaturated 14-membered trans-N 2 O 2 diimine macrocycle 6,7,15,16-tetrahydrodibenzo[f,m][1,8,4,11]dioxadiazacyclotetradecine, presumably via seven-membered 2,3-dihydro-1,4-benzoxazepine
TL;DR: Asymmetric addition of hydrogen cyanide to various aldehydes in the presence of a catalytic amount of cyclo-((S)-leucyl-(S)-histidyl) affords the corresponding cyanohydrins in moderate to good optical yields as discussed by the authors.
Abstract: Asymmetric addition of hydrogen cyanide to various aldehydes in the presence of a catalytic amount of cyclo-((S)-leucyl-(S)-histidyl) affords the corresponding cyanohydrins in moderate to good optical yields. The reaction of benzaldehyde with hydrogen cyanide gives (S)-2-hydroxy-2-phenylacetonitrile (85%, 55% ee) whose stereochemistry is found to be opposite to our previous result using cyclo-((S)-phenylalanyl-(S)-histidyl).
TL;DR: In the presence of BF 3 · Et 2 O, the major products are the corresponding syn -5-hydroxy-4-methyl- E -pent-2-enes (22) and (23) as mentioned in this paper.
TL;DR: In this paper, the anodic oxidation of benzyl alcohol has been studied in a two-phase system containing both the redox mediator, ClO-/Cl-, and a phase transfer catalyst (PTC), and the reaction mechanism and the factors which affect the current efficiency of benzaldehyde production were explored.
Abstract: The anodic oxidation of benzyl alcohol has been studied in the two-phase system containing both the redox mediator, ClO-/Cl-, and a phase transfer catalyst (PTC). The reaction mechanism and the factors which affect the current efficiency of benzaldehyde production were explored. The experimental results reveal that the rate determining step shifts from the shuttling rate of the redox ions to the anodic oxidation of Cl- when the agitation rate changes from 400 to 500 rpm in the presence of 0.05m Bu4NHSO4. The results also show that benzyl alcohol is mainly oxidized in the organic phase by the shuttling of the ClO-/Cl- mediator. The current efficiency is mainly governed by the pH value and the nature of the organic solvent as well as the types and the concentration of PTC. The current efficiency is slightly affected by both the current density and temperature.