Showing papers on "Benzaldehyde published in 1991"
TL;DR: In this article, the knoevenagel condensation of carbonyl substrates with acidic methylene reagents proceeds smoothly in presence of zinc chloride, without the need for solvent, to produce products of good purity in high yield.
268 citations
TL;DR: In this paper, the stereoselectivity of imines of benzaldehyde and cinnamaldehyde with ketenes generated by the reaction of optically active oxazolidinone acid chlorides with triethylamine was compared.
Abstract: The stereoselectivity of the reaction of imines of benzaldehyde and cinnamaldehyde with ketenes generated by the reaction of optically active oxazolidinone acid chlorides with triethylamine and complexed ketenes generated by photolysis of optically active oxazolidine ― and oxazolidinone-chromium-carbene complexes in the presence and absence of added triethylamine was compared. The absolute stereochemistry was determined primarily by the structure of the chiral auxiliary. The relative (cis-trans) stereochemistry was determined primarily by the structure of the imine and the free or bound character of the ketene. Triethylamine addition to reactions of carbene complexes afforded results that closely paralleled that of acid chloride generated ketenes. A mechanistic scheme accounting for these results and the general trends observed in other ketene/imine cyclizations is provided
129 citations
TL;DR: The data conclusively show anaerobic growth of a pure culture on tolucne and suggest that toluene is anaerobically degraded via benzoyl-CoA and imply that water functions as the source of the hydroxyl group in a toLUene methylhydroxylase reaction.
Abstract: The anaerobic degradation of toluene has been studied with whole cells and by measuring enzyme activities. Cultures of Pseudomonas strain K 172 were grown in mineral medium up to a cell density of 0.5 g of dry cells per liter in fed-batch culture with toluene and nitrate as the sole carbon and energy sources. A molar growth yield of 57 g of cell dry matter formed per mol toluene totally consumed was determined. The mean generation time was 24 h. The redox balance between toluene consumed (oxidation and cell material synthesis) and nitrate consumed (reduction to nitrogen gas and assimilation as NH3) was 77% of expectation if toluene was completely oxidized; this indicated that the major amount of toluene was mineralized to CO2. It was tested whether the initial reaction in anaerobic toluene degradation was a carboxylation or a dehydrogenation (anaerobic hydroxylation); the hypothetical carboxylated or hydroxylated intermediates were tested with whole cells applying the method of simultaneous adaptation; cells pregrown on toluene degraded benzyl alcohol, benzaldehyde, and benzoic acid without lag, 4-hydroxybenzoate and p-cresol with a 90 min lag phase, and phenylacetate after a 200 min lag phase. The cells were not at all adapted to degrade 2-methylbenzoate, 4-methylbenzoate, o-cresol, and m-cresol, nor did these compounds support growth within a few days after inoculation with cells grown on toluene. In extracts of cells anaerobically grown on toluene, benzyl alcohol dehydrogenase, benzaldehyde dehydrogenase, and benzoyl-CoA synthetase (AMP forming) activities were present. The data (1) conclusively show anaerobic growth of a pure culture on toluene; (2) suggest that toluene is anaerobically degraded via benzoyl-CoA; (3) imply that water functions as the source of the hydroxyl group in a toluene methylhydroxylase reaction.
96 citations
TL;DR: It appears that benzaldehyde is the metabolite responsible for the effect of toluene in accelerating reactive oxygen production within the nervous system, and may also contribute to the overall neurotoxicity of toLUene.
72 citations
TL;DR: The ruthenium benzyne complex (PMe 3 ) 4 Ru(η 2 -C 6 H 4 ) (1) as discussed by the authors is analogous to that or early rather than late organo-transition-metal complexes.
Abstract: Thermolysis of (PMe 3 ) 4 Ru(Ph)(Me) or (PMe 3 ) 4 Ru(Ph) 2 leads to the ruthenium benzyne complex (PMe 3 ) 4 Ru(η 2 -C 6 H 4 ) (1) by a mechanism that involves initial reversible dissociation of phosphine. In many ways, its chemistry is analogous to that or early rather than late organo-transition-metal complexes. Thus, compound 1 undergoes apparent σ-bond metathesis reactions with the C-H bonds of benzene or toluene solvent (the reverse of the formation of 1), the N-H bond in aniline, and O-H bonds of p-cresol, 2-propanol, and water. The monomeric hydroxide complex resulting from addition of water has been structurally characterized. Compound 1 also undergoes insertion reactions with a variety of unsaturated organic molecules, including ethylene, di-p-tolylacetylene, benzaldehyde, and benzonitrile. Qualitative mechanistic studies on the O-H addition of p-cresol and the insertion of benzaldehyde and benzonitrile are reported
63 citations
63 citations
TL;DR: Asymmetric induction in the product of the Baylis-Hillman reaction between an aldehyde and an acrylic compound in the presence of a tertiary amine base, may be controlled by chirality in the acrylic ester, base or solvent as mentioned in this paper.
Abstract: Asymmetric induction in the product of the Baylis-Hillman reaction between an aldehyde and an acrylic compound in the presence of a tertiary amine base, may be controlled by chirality in the aldehyde, acrylic ester, base or solvent; R-CHO + CH2=CH-COOR' (B:, solvent) →CH2=C(C∗HROH)-COOR' Examples of each are described but the best stereochemical result, 100% ee, is obtained from the high pressure reaction of benzaldehyde with (-)-menthyl acrylate.
62 citations
46 citations
Patent•
28 Mar 1991
TL;DR: A process for the predominantly producing R(-)-mandelic acid or a derivative thereof which comprises subjecting (i) a R,S-mandelonitrile or derivative thereof, or (ii) a mixture of prussic acid and benzaldehyde or a derivatives of benzaldehyde to the action of a microorganism selected from the group consisting of the genus Aureobacterium, Pseudomonas, Caseobacter, Alcaligenes, Acinetobacteria, Brevibacteria, Nocardia, and Bacillus or treated cells thereof,
Abstract: A process for the predominantly producing R(-)-mandelic acid or a derivative thereof which comprises subjecting (i) R,S-mandelonitrile or a derivative thereof, or (ii) a mixture of prussic acid and benzaldehyde or a derivative of benzaldehyde to the action of a microorganism selected from the group consisting of the genus Aureobacterium, Pseudomonas, Caseobacter, Alcaligenes, Acinetobacter, Brevibacterium, Nocardia, and Bacillus or treated cells thereof, which the microorganism is capable of stereospecifically hydrolyzing a nitrile group of the R,S-mandelonitrile or a derivative thereof, in a neutral or basic aqueous reaction system to produce the R(-)-mandelic acid.
42 citations
TL;DR: In this paper, a time dependence for the reaction of a 2-lithiooxazole with benzaldehyde is described, and a rationale for this behavior is offered, and the use of sec-butyllithium/catalytic lithium tetramethylpiperidide allows preferential formation of 4 lithio-2,5-diphenyloxazoles.
Abstract: Reactions of 2-α-, 2-, 4-, and 5-lithiooxazoles are used to prepare various substituted derivatives. Previously unrecognized time dependence for the reaction of a 2-lithiooxazole with benzaldehyde is described, and a rationale for this behavior is offered. Competitive reactions occur when the readily available 2,5-diphenyloxazole is treated with n-butyllithium. Deprotonation of the ortho position of the 2-phenyl group and addition of n-butyl to the 2-position of the oxazole compete with the desired 4-lithiation. The use of sec-butyllithium/catalytic lithium tetramethylpiperidide allows preferential formation of 4-lithio-2,5-diphenyloxazole
42 citations
TL;DR: In this article, the four-membered-ring heterocycles are quite stable, mainly due to the large steric hindrance of the substituents, and they react very readily with aldehydes and ketones, according to a [2+2] cycloaddition.
TL;DR: In this paper, reactions of four aldehydes with five aromatic compounds have been carried out on a series of USY zeolites with unit cell size in the 24.56 to 24.25-t1 range.
TL;DR: The chiral dithiepine 3 was selectively oxidized to all possible oxides: the sulfoxide 9, the sulfone 16, sulfone-sulfoxide 20, the disulfoxide 21, and disulfone 22.
Abstract: The chiral dithiepine 3 was selectively oxidized to all possible oxides: the sulfoxide 9, the sulfone 16, the sulfone-sulfoxide 20, the disulfoxide 21, and the disulfone 22. The sulfinyl oxygens of 9, 14, 20, and 21 are always in the pseudoaxial configuration, as shown by the X-ray structure determination of 11a. Reaction of the anions of 3, 9, and 16 with methyl iodide, benzaldehyde, or acetophenone occurs efficiently. The stereoselectivity of the processes is high and maximized in sulfoxide 9, where the contributions of the chiral binaphthyl residue and the sulfoxide appear to occur synergistically. The alcohols derived from reaction of the anions of 3, 9, and 16 with benzaldehyde and acetophenone were also prepared in high yield and stereoselectivity via reduction or methylation of the phenyl ketone 8 and of its oxidized homologues 14 and 19. Alcohol 6a, prepared in 8.2 ratio in the reaction of 3 with benzaldehyde, was obtained as a single diastereoisomer in the reduction of 8 with lithium aluminum hydride
01 Jan 1991
TL;DR: In this article, the authors studied the oxidation of benzyl radicals by UV absorption in shock waves over the temperature range 1200-1500 K. They suggested that the reaction was initiated by benzyl and dibenzyl dissociation mechanisms generating H atoms which further react with O2.
Abstract: The oxidation of benzyl radicals was studied by UV absorption in shock waves over the temperature range 1200–1500 K. No direct attack of benzyl by O2 was observed. It is suggested that the reaction was initiated by benzyl and dibenzyl dissociation mechanisms generating H atoms which further react with O2. Toluene, benzaldehyde and benzyl alcohol were identified as relatively stable intermediates. Rate coefficients for the benzyl/dibenzyl dissociation mechanism generating H atoms and for the reactions HO+C6H5CH2→C6H5CH2OH, HO+C6H5CH2OHH2O+C6H5CH2O, and HO2+C6H5CH2HO+C6H5CH2O were fitted. HO concentrations markedly rise only after the disappearance of benzyl.
TL;DR: In this article, the preparation of α,β-unsaturated ketones is performed in a one-pot procedure by subsequent treatment of diethyl lithiomethyl-phosphonate with nitriles, followed by addition of carbonyl compounds and hydrolysis.
Abstract: The preparation of α,β-unsaturated ketones is performed in a one-pot procedure by subsequent treatment of diethyl lithiomethyl-phosphonate with nitriles, followed by addition of carbonyl compounds and hydrolysis
TL;DR: In this article, a mechanism involving a electron transfer process was proposed for the photochemical reaction of an aromatic aldehyde with indole or 2-methylindole gave 3,3′-diindolylmethanes in ca. 50% yield.
TL;DR: Sodium methoxide catalyzed aldol condensation of ethyl α-azidoacetate with 4-[bis-(tert-butoxy)phosphorylmethyl]benzaldehyde (4) provided methyl α-enzaldehyde-4-[bis(tert)-butoxy)-phosphoricmethyl]cinnamate (5) which undergoes facile hydrogenation in the presence of 10 % palladium on carbon to yield methyl 4[bis(TERt- butoxy)-phenylalaninate (6) as discussed by the authors.
Abstract: Sodium methoxide catalyzed aldol condensation of ethyl α-azidoacetate with 4-[bis-(tert-butoxy)phosphorylmethyl]benzaldehyde (4) provides methyl α-azido-4-[bis(tert-butoxy)phosphorymethyl]cinnamate (5), which undergoes facile hydrogenation in the presence of 10 % palladium on carbon to yield methyl 4-[bis(tert-butoxy)phosphorylmethyl]-DL-phenylalaninate (6)
TL;DR: The C2-symmetric aziridines 1 and 1′ (available from (+)- and (−)-tartaric acid, respectively) are excellent chiral auxiliaries for asymmetric alkylation and aldol reactions as mentioned in this paper.
TL;DR: In this paper,,β-unsaturated aldehydes, giving only the elimination products, are in one step transformed into 4-substituted (E, E)-(S, S)-1, 1-bis (p-tolylsulfinyl)-1-3-butadiene.
Patent•
28 Jun 1991
TL;DR: A method for inhibiting sprouting of tubers including the step of exposing tubers to the aromatic aldehydes or alcohols: benzaldehyde, salicylaldehyde, cinnamaldehyde, hydrocinnamide, cuminaldehyde, thymol, or mixtures thereof as discussed by the authors.
Abstract: A method for inhibiting sprouting of tubers including the step of exposing tubers to the aromatic aldehydes or alcohols: benzaldehyde, salicylaldehyde, cinnamaldehyde, hydrocinnamaldehyde, cuminaldehyde, thymol, or mixtures thereof.
TL;DR: Direct fluorination of aromatic substrates, PhZ (Z=Cl, CHO, CH(OCH 2 ) 2, NO 2, CO 2 CH 2 CH 3, OH, NHCH 3, OCH 3, CH 3 ), in the presence and absence of BCl 3 or AlCl 3, has been investigated.
Abstract: Direct fluorination of aromatic substrates, PhZ (Z=Cl, CHO, CH(OCH 2 ) 2 , NO 2 , CO 2 CH 2 CH 3 , OH, NHCH 3 , OCH 3 , CH 3 ), in the presence and absence of BCl 3 or AlCl 3 , has been investigated
TL;DR: In this article, new routes to these reactive metal-( Z )-crotyl reagents utilize 2-butyne and s-cis -butadiene organomolybdenum intermediates instead of (Z )-potassium.
TL;DR: In this paper, a grafting procedure for poly(methylhydrosiloxane) was introduced to the residual vinyl groups of commercial macroporous styrene/ divinylbenzene copolymers using a platinum-containing catalyst.
TL;DR: X-ray structure analysis of the THF adduct reveals that NCCHCOOMe group bonds to ruthenium not through the methine carbon but the cyano group as mentioned in this paper.
Abstract: Carbon-hydrogen bond oxidative addition of alkyl cyanoacetate to Ru(C2H4)(PPh3)3 in benzene at room temperature gives mer-RuH(NCCHCOOR)(NCCH2COOR)(PPh3)3 (R = Me, Et) accompanied by the liberation of ethylene. X-Ray structure analysis of the THF adduct (R = Me) reveals that NCCHCOOMe group bonds to ruthenium not through the methine carbon but the cyano group. These complexes react with benzaldehyde and methyl iodide to give alkyl (E)-1-cyanocinnamate and alkyl 2-cyanopropionate, respectively.
TL;DR: In this article, it was shown that trialkylsilyl nitronic esters are not reaction intermediates, and that the one-pot reaction of aldehydes with nitrecompounds in the presence of Et3N, Bu4NF·3H2O and tBuMe2SiCl can be readily obtained in high yields.
TL;DR: The inside alkosy effect has been found to be important in the addition of α-(alkoxy) allylstannanes to aldehydes in the presence of BF3·Et2O as mentioned in this paper.
TL;DR: In this article, the dilithium or disodium salts of the bistosylhydrazones of the 2-(2-formylphenyl)benzaldehydes were used to heat the phenanthrenes.
TL;DR: In this paper, the reactions of azoles with o-fluoro-acetophenone, -benzaldehyde and o-benzophenone in the presence of anhydrous potassium carbonate have been investigated.
Abstract: The reactions of some azoles with o-fluoro-acetophenone , -benzaldehyde and -benzophenone in dimethyl sulfoxide solution in the presence of anhydrous potassium carbonate have been investigated. In addition to the expected substitution products, cyclization reactions frequently occurred to give carbinols in the case of the reactions of o-fluoro-acetophenone and -benzophenone, and cyclic ketones in the case of the reactions with o-fluorobenzaldehyde . Fluoren-9-ol and related carbinols containing heteroaromatic nuclie are readily converted in dimethyl sulfoxide solution into the corresponding ketones by treatment with anhydrous potassium carbonate. When treated with ethanolic alkali, 2′-(benzimidazol-1′-yl) acetophenone undergoes a remarkable transformation to give 1-(2-aminophenyl)quinolin-4(1H)-one.
TL;DR: The [3 + 2] cycloaddition of 5-alkoxyoxazoles with aldehydes in the presence of the organoaluminum reagent, which was prepared from (±)-2,2′-dihydroxy-1,1′-dinaphthyl and AlMe3, gave cis-4alkoxycarbonyl-2-oxazolines in a high regio-and stereoselective manner as mentioned in this paper.