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Showing papers on "Benzoic acid published in 1990"


Journal ArticleDOI
TL;DR: In this paper, the authors used the Langmuir-Hinshelwood (L-H) kinetics for each solute to predict the mineralization rate at any solute concentration in aerated, aqueous suspensions of TiO 2 with near uv light.

258 citations


Journal ArticleDOI
TL;DR: In this paper, the authors showed that the conversion of cinnamic acids into benzoic acids does not involve cinnamoyl CoA esters as intermediates.
Abstract: Feeding of cinnamic acid and ferulic acid to non-treated and chitosan-treated cell suspension cultures of Vanilla planifolia resulted in the formation of trace amounts of p-hydroxy benzoic acid (5.2 micrograms per gram fresh weight of cells) and vanillic acid (6.4 micrograms per gram fresh weight of cells), respectively. Addition of a 4-hydroxycinnamate: CoA-ligase inhibitor, 3,4-(methylenedioxy)-cinnamic acid (MDCA), resulted in a reduced biosynthesis of ligneous material with a simultaneous significant increased vanillic acid formation (around 75 micrograms per gram fresh weight of cells). A K(1) of 100 micromolar for 4-hydroxycinnamate: CoA-ligase in a crude preparation was estimated for this inhibitor. It is suggested that the conversion of cinnamic acids into benzoic acids does not involve cinnamoyl CoA esters as intermediates. Feeding of (14)C-cinnamic acid and (14)C-ferulic acid to cells treated with MDCA indicate that cinnamic acid, but not ferulic acid, is a precursor of vanillic acid in these cultivated cells of V. planifolia.

91 citations


Book
31 Dec 1990
TL;DR: In this paper, the Hubach analysis was used to evaluate the stability of wine microorganisms and their ability to tolerate tartaric acid and its salts, as well as copper, iron, and phosphorus.
Abstract: Section I-Sampling, Fermentation, and Production Analysis.- 1 / Fruit Quality and Soluble Solids.- 2 / Alcoholometry.- 3 / Extract.- 4 / Hydrogen Ion (pH) and Fixed Acids.- 5 / Volatile Acids.- 6 / Carbohydrates: Reducing Sugars.- 7 / Phenolic Compounds and Wine Color.- 8 / Oxygen, Carbon Dioxide, and Ascorbic Acid.- Section II-Microbial Stability.- 9 / Sulftir Dioxide.- 10 / Sulfur Containing Compounds.- 11 / Other Preservatives: Sorbic Acid, Benzoic Acid, and Dimethyldicarbonate.- 12 / Wine Microbiology.- Section III-Chemical Stability.- 13 / Tartaric Acid and its Salts.- 14 / Copper.- 15 / Iron and Phosphorus.- 16 / Nitrogenous Compounds.- Section IV-Remedial Actions.- 17 / Fining and Fining Agents.- 18 / Correction of Tartrate Instabilities.- 19 / Removal of Copper and Iron-The Hubach Analysis.- Appendixes.- Appendix I /Chromatographic Techniques.- Appendix II /Laboratory Reagent Preparation.- Appendix III /Laboratory Media and Stains.

74 citations


Journal ArticleDOI
TL;DR: Two enzymes of the xylene degradative pathway encoded by the plasmid TOL of a Gram-negative bacterium Pseudomonas putida were purified and characterized, though they were not capable of oxidizing aliphatic alcohols and aldehydes.
Abstract: Benzyl alcohol dehydrogenase and benzaldehyde dehydrogenase, two enzymes of the xylene degradative pathway encoded by the plasmid TOL of a Gram-negative bacterium Pseudomonas putida, were purified and characterized. Benzyl alcohol dehydrogenase catalyses the oxidation of benzyl alcohol to benzaldehyde with the concomitant reduction of NAD+; the reaction is reversible. Benzaldehyde dehydrogenase catalyses the oxidation of benzaldehyde to benzoic acid with the concomitant reduction of NAD+; the reaction is irreversible. Benzyl alcohol dehydrogenase and benzaldehyde dehydrogenase also catalyse the oxidation of many substituted benzyl alcohols and benzaldehydes, respectively, though they were not capable of oxidizing aliphatic alcohols and aldehydes. The apparent Km value of benzyl alcohol dehydrogenase for benzyl alcohol was 220 μM, while that of benzaldehyde dehydrogenase for benzaldehyde was 460 μM. Neither enzyme contained a prosthetic group such as FAD or FMN, and both enzymes were inactivated by SH-blocking agents such as N-ethylmaleimide. Both enzymes were dimers of identical subunits; the monomer of benzyl alcohol dehydrogenase has a mass of 42 kDa whereas that of the monomer of benzaldehyde dehydrogenase was 57 kDa. Both enzymes transfer hydride to the pro-R side of the prochiral C4 of the pyridine ring of NAD+.

74 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of oxygen concentration on the activity of purified apple polyphenol oxidase (PPO) was studied with 4-methylcatechol, chlorogenic acid, or (+)-catechin as phenolic substrate.
Abstract: The effect of oxygen concentration on the activity of purified apple polyphenol oxidase (PPO) was studied with 4-methylcatechol, chlorogenic acid, or (+)-catechin as phenolic substrate. For these three phenolic compounds, the kinetic pattern was consistent with a sequential mechanism for the binding of oxygen and phenol. Benzoic acid is a competitive inhibitor with respect to 4-methylcatechol and uncompetitive with respect to oxygen, which suggests that apple PPO combines with oxygen before it does with the phenolic substrate. Oxygen uptake of a two-phenolic compound mixture by apple PPO was studied in air-saturated solutions. An equation that contains only the kinetic parameters Km and Vm of each phenol was developed. For the two mixtures tested, 4-methylcatechol/caffeic acid and (+)-catechin/ chlorogenic acid, the experimental values of oxygen uptake were in excellent agreement with the caiculated curves. The equation can be extended to a multicomponent solution and therefore can be used for the study of oxidability of mixtures of phenolic compounds in model solutions by PPO.

72 citations


Journal ArticleDOI
TL;DR: It was concluded that nicotinic acid is transported through the intestinal brush-border membrane by a carrier-mediated system and the system can recognize some acidic drugs with a monocarboxylic group and the pH dependent intestinal uptake can be ascribed to the proton-coupled and active carrier- mediated transport mechanism.
Abstract: The intestinal transport of [14C]nicotinic acid was investigated at 27 degrees C by using brush-border membrane vesicles (BBMV) isolated from the rat small intestine. The osmolarity sensitive uptake by BBMV showed a remarkable overshoot phenomenon in the presence of an inward-directed H+ gradient (pHin = 7.5, pHout = 6.0). In contrast, the imposition of a Na+ gradient ([Na+]in = 0 mM, [Na+]out = 100 mM) had no stimulatory effect on the uptake of [14C]nicotinic acid. The remarkable pH-dependence of the initial uptake showing an increase of the uptake rate with decreasing the extravesicular pH disappeared completely in the presence of a structural analogue, isonicotinic acid, at pH below 6.5. In the presence of a H+ gradient, the initial uptake of [14C]nicotinic acid was saturable with the apparent Kt of 4.43 mM and Jmax of 2.55 nmol/mg protein/15 s. The uptake was increased by the imposition of an inside-positive membrane potential and was significantly inhibited by monocarboxylic acids such as benzoic acid, salicylic acid, acetic acid, propionic acid, valproic acid and L-lactic acids as well as two isomers (isonicotinic acid and picolinic acid). The uptake was not inhibited by nicotinamide, nicotinyl alcohol, D-glucose, p-aminohippuric acid, glycyl-L-proline, succinic acid and an exchange transport inhibitor. From these results it was concluded that nicotinic acid is transported through the intestinal brush-border membrane by a carrier-mediated system and the system can recognize some acidic drugs with a monocarboxylic group. The pH dependent intestinal uptake of nicotinic acid can be ascribed to the proton-coupled and active carrier-mediated transport mechanism rather than a simple diffusion of the undissociated nicotinic acid to follow a pH-partition hypothesis.

62 citations


Journal ArticleDOI
TL;DR: It is concluded that the side chain degrading enzyme system accepts the 4-methoxylated substrates while the demethylation occurs at the benzoic acid level, and 4-Methoxy substituted cinnamic acids are better substrates for this enzyme than 4-hydroxy substitutedcinnamic acid.
Abstract: Feeding of 4-methoxycinnamic acid, 3,4-dimethoxycinnamic acid and 3,4,5-trimethoxycinnamic acid to cell suspension cultures of Vanilla planifolia resulted in the formation of 4-hydroxybenzoic acid, vanillic acid, and syringic acid, respectively. The homologous 4-methoxybenzoic acids were demethylated to the same products. It is concluded that the side chain degrading enzyme system accepts the 4-methoxylated substrates while the demethylation occurs at the benzoic acid level. The demethylating enzyme is specific for the 4-position. Feeding of [O-14C-methyl]-3,4-dimethoxycinnamic acid revealed that the first step in the conversion is the glycosylation of the cinnamic acid to its glucose ester. A partial purification of a UDP-glucose: trans-cinnamic acid glucosyltransferase is reported. 4-Methoxy substituted cinnamic acids are better substrates for this enzyme than 4-hydroxy substituted cinnamic acid. It is suggested that 4-methoxy substituted cinnamic acids are intermediates in the biosynthetic conversion of cinnamic acids to benzoic acids in cells of V. planifolia.

59 citations


Journal ArticleDOI
TL;DR: Results indicate a specific, possibly axonal flow-mediated transport of aromatic acids from the nasal mucosa to the olfactory lobe of the brain, and the toxicological significance of these results remains to be studied.
Abstract: Autoradiography of male mice following inhalation of the radioactively labelled solvents, toluene, xylene, and styrene, revealed an accumulation of non-volatile metabolites in the nasal mucosa and olfactory bulb of the brain. Since no accumulation occurred after benzene inhalation, it was assumed that the activity represented aromatic acids, which are known metabolites of these solvents. This was supported by the finding that also radioactive benzoic acid (main metabolite of toluene) and salicylic acid accumulated in the olfactory bulb. High-performance liquid chromatography revealed that after toluene inhalation (for 1 hr), nasal mucosa and olfactory bulb contained mainly benzoic acid, with a strong accumulation in relation to blood plasma, and considerably less of its glycine conjugate, hippuric acid. After xylene inhalation, on the other hand, methyl hippuric acid dominated over the non-conjugated metabolite, toluic acid. The results indicate a specific, possibly axonal flow-mediated transport of aromatic acids from the nasal mucosa to the olfactory lobe of the brain. The toxicological significance of these results remains to be studied.

58 citations


Journal ArticleDOI
TL;DR: In this paper, a resonance enhanced multi photon ionization (REMPI) spectra of the para-amino benzoic acid (PABA) molecule and its methyl and n-butyl ester were obtained in this way.
Abstract: The technique of laser desorption followed by jet cooling allows wavelength‐selective as well as mass‐selective detection of molecules, desorbed from a surface without fragmentation. Resonance enhanced multi photon ionization (REMPI) spectra of the para‐amino benzoic acid (PABA) molecule and its methyl and n‐butyl ester were obtained in this way. The origin of the S1←S0 transition in PABA was found at 34173±2 cm−1. The adiabatic ionization potential of PABA was determined as 7.998±0.001 eV. In addition, jet‐cooled REMPI spectra of the PABA dimer and its ring‐deuterated isotopes were recorded. The dimer is formed by two identical hydrogen bonds between the carboxylic acid groups. The excitation in the dimer is found to be almost completely localized in one monomer unit. Clusters of PABA molecules with molecules seeded in the beam (argon, methanol, water) were resonantly detected as well, using PABA as the chromophore.

55 citations



Journal ArticleDOI
TL;DR: From these observations, acidic drugs could be transported by a carrier-mediated system for monocarboxylic acids at the BBB and the transport system was not changed by the disease state.
Abstract: The relationship of the transports between acidic drugs and monocarboxylic acids through the blood-brain barrier (BBB) was examined using the carotid artery injection technique in rats. The BBB uptakes of [3H]acetic acid and [14C]salicylic acid were significantly reduced by the presence of the respective unlabeled compounds, valproic acid, lactic acid, benzoic acid, nicotinic acid or beta-lactam antibiotics (benzylpenicillin, propicillin and cefazolin), but was not reduced by choline, phenylalanine and a basic drug, eperisone. A remarkable pH dependency was observed for the BBB uptake of [14C]salicylic acid at the pH region of 4.0 to 7.4. Interestingly, 10 mM of salicylic acid diminished significantly the pH dependent BBB uptake of [14C]salicylic acid. Similar results were obtained in the BBB uptake of [14C]nicotinic acid. No significant difference was observed in the transport of monocarboxylic acids through the BBB between normotensive Wistar KY rats (WKY) and stroke-prone spontaneously hypertensive rats (SHRSP). From these observations, acidic drugs could be transported by a carrier-mediated system for monocarboxylic acids at the BBB and the transport system was not changed by the disease state.

Journal ArticleDOI
TL;DR: In this paper, 13C-1 phenol was converted to 13C 4 benzoic acid by an anaerobic phenol converting enrichment, which did not form p-hydroxybenzoate as a free intermediate but converted phenol and then, probably by another organism, to benzoate.
Abstract: 13C-1 phenol was converted to 13C-4 benzoic acid by an anaerobic phenol converting enrichment, which did not form p-hydroxybenzoate as a free intermediate but converted p-hydroxybenzoate first phenol and then, probably by another organism, to benzoate. No isotopic effect was observed using D5- and D6-phenol, suggesting that the breakage of the C-H bond on the C-4 position was not a rate limiting step in the conversion.

Journal ArticleDOI
01 Apr 1990-Langmuir
TL;DR: In this paper, surface-enhanced Raman scattering (SERS) has been observed from a model acrylic adhesive deposited onto silver island films, indicating that the observed Raman signal was characteristic of the interface and not of the bulk of the films.
Abstract: : Surface-enhanced Raman scattering (SERS) has been observed from a model acrylic adhesive deposited onto silver island films. SERS spectra of the adhesive system were very similar to SERS spectra of o-benzoic sulphimide (saccharin), a component of the curing system of the adhesive, and to normal Raman spectra of the sodium salt of saccharin. When saccharin was replaced in the curing system by benzoic acid, SERS spectra of the adhesive were similar to SERS spectra of benzoic acid and to normal Raman spectra of benzoic acid salts. The intensity of the SERS spectra was independent of the thickness of the adhesive films, indicating that the observed Raman signal was characteristic of the interface and not of the bulk of the films. These results demonstrate that saccharin and benzoic acid wee preferentially adsorbed at the silver surface to form metal salts and that surface-enhanced Raman scattering can be used for non- destructive characterization of interphases between polymer films and SERS- active metal substrates as long as the films are not so thick that normal Raman scattering from the bulk is comparable in intensity to the SERS from the interphase.

Journal ArticleDOI
TL;DR: Both PABA and benzocaine were extensively N-acetylated during percutaneous absorption and the metabolism of these compounds should be considered in an accurate assessment of absorption after topical application.
Abstract: The percutaneous absorption and metabolism of three structurally related compounds, benzoic acid, p-aminobenzoic acid (PABA), and ethyl aminobenzoate (benzocaine), were determined in vitro through hairless guinea pig skin. Benzocaine was also studied in human skin. Absorption of benzocaine was rapid and similar through both viable and nonviable skin. The absorption of the two acidic compounds, benzoic acid and PABA, was greater through nonviable skin. A small portion (6.9%) of absorbed benzoic acid was conjugated with glycine to form hippuric acid. Although N-acetyl-benzocaine had not been observed as a metabolite of benzocaine when studied by other routes of administration, both PABA and benzocaine were extensively N-acetylated during percutaneous absorption. Thus, the metabolism of these compounds should be considered in an accurate assessment of absorption after topical application.

Journal Article
TL;DR: The results suggest that cytochrome P-450, rather than alcohol dehydrogenase, was responsible for the metabolism of benzyl alcohol to benzaldehyde.
Abstract: The in vitro metabolism of [14C]toluene by liver microsomes and liver slices from male Fischer F344 rats and human subjects has been compared. Rat liver microsomes produced only benzyl alcohol from toluene. Liver microsomes from human subjects metabolized toluene to benzyl alcohol, benzaldehyde, and benzoic acid. Liver microsomes from one human donor also produced p-cresol and o-cresol. The overall rate of toluene metabolism by human liver microsomes was 9-fold greater than by rat liver microsomes. Human liver microsomal metabolism of benzyl alcohol to benzaldehyde required NADPH and was inhibited by carbon monoxide and high pH (pH 10). but was not inhibited by ADP-ribose or sodium azide. These results suggest that cytochrome P-450, rather than alcohol dehydrogenase, was responsible for the metabolism of benzyl alcohol to benzaldehyde. Human and rat liver slices metabolized toluene to hippuric acid and benzoic acid. The overall rate of toluene metabolism by human liver slices was 1.3-fold greater than by rat liver slices. Cresols and cresol conjugates were not detected in human or rat liver slice incubations. Covalent binding of [14C]toluene to human liver microsomes and slices was 21-fold and 4-fold greater than to the comparable rat liver preparations. Covalent binding did not occur in the absence of NADPH, was significantly decreased by coincubation with cysteine, glutathione, or superoxide dismutase, and was unaffected by coincubation with lysine. Protease and ribonuclease digestion decreased the amount of toluene covalently bound to human liver microsomes by 78% and 27% respectively. Acid washing of human liver microsomes had no effect on covalent binding.(ABSTRACT TRUNCATED AT 250 WORDS)

Journal ArticleDOI
TL;DR: In this article, a review of the microbial production of cis,cis -muconic acid from benzoic acid using a total bioreactor system including downstream processing is presented.

Journal ArticleDOI
TL;DR: In this paper, the authors measured diffusion coefficients for acridine, phenanthrene, and benzoic acid at infinite dilution in either supercritical carbon dioxide, or a mixture of super critical carbon dioxide with 5.5 mol % methanol as entrainer.
Abstract: Diffusion coefficients are measured for acridine, phenanthrene, and benzoic acid at infinite dilution in either supercritical carbon dioxide, or a mixture of supercritical carbon dioxide with 5.5 mol % methanol as entrainer. These data indicate that diffusion of acridine and benzoic acid are markedly reduced by the presence of small amounts of methanol. Phenanthrene is not affected to as great an extent. These observations are in qualitative agreement with equilibrium solubility and spectroscopic measurements for these same systems, indicating the formation of clusters of the entrainer (methanol) about benzoic acid and acridine. It is proposed that the size of the diffusing cluster, not the size of the solute molecule, should be considered when predicting diffusion rates.

Journal ArticleDOI
TL;DR: Two strains of Alcaligenes denitrificans, designated BRI 3010 and BRI 6011, were isolated from polychlorinated biphenyl (PCB)-contaminated soil using 2,5-dichlorobenzoic acid and 2,4-DCBA, respectively, as sole carbon and energy sources, suggesting the importance of an unsubstituted carbon six of the aromatic ring.
Abstract: Two strains of Alcaligenes denitrificans, designated BRI 3010 and BRI 6011, were isolated from polychlorinated biphenyl (PCB)-contaminated soil using 2,5-dichlorobenzoic acid (2,5-DCBA) and 2,4-DCBA, respectively, as sole carbon and energy sources. Both strains degraded 2-chlorobenzoic acid (2-CBA), 2,3-DCBA, and 2,5-DCBA, and were unable to degrade 2,6-DCBA. BRI 6011 alone degraded 2,4-DCBA. Growth of BRI 6011 in yeast extract and 2,6-DCBA induced pyrocatechase activity, but 2,6-DCBA was not degraded, suggesting the importance of an unsubstituted carbon six of the aromatic ring. Metabolism of the chlorinated substrates resulted in the stoichiometric release of chloride, and degradation proceeded by intradiol cleavage of the aromatic ring. Growth of both strains on 2,5-DCBA induced pyrocatechase activities with catechol and chlorocatechols as substrates. In contrast to dichlorobenzoic acids, growth on 2-CBA, benzoic acid, mono- and dihydroxybenzoic acids induced a pyrocatechase activity against catechol only. Although 2,4-DCBA was a more potent inducer of both pyrocatechase activities, its utilization by BRI 6011 was inhibited by 2,5-DCBA. Specific uptake rates using resting cells were highest with 2-CBA, except when the resting cells had been previously grown on 2,5-DCBA, in which case 2,5-DCBA was the preferred substrate. The higher rates of 2,5-DCBA uptake obtained by growth on that substrate, suggested the existence of a separately induced uptake system for 2,5-DCBA.

Journal ArticleDOI
TL;DR: Equilibrium dialysis experiments indicate that benzoic acid can bind to the alpha and gamma isozymes in the absence of organic substrate, and a scheme in which benzosic acid binds to the oxy-form of tyrosinase is proposed to account for the kinetic and equilibrium results.

Journal ArticleDOI
TL;DR: Glycosidation of N -acetylneuraminic acid by phase-transfer catalysis in chloroform-aqueous alkali gave several known and some new aryl α-ketosides in a short reaction time and in good yields.

Journal ArticleDOI
TL;DR: In this article, the formation of amide groups on the aminopropylsilica surface was confirmed and the presence of stable ester-type surface compounds with silanol groups was detected.

Journal ArticleDOI
TL;DR: In this article, a gas-phase absorption spectrum of the jet-cooled benzoic acid monomer was identified for the first time. But the spectral lines have a Lorentzian shape with a line width of 6.5 cm-I, corresponding to an intersystem crossing rate of 1.2 x s-I.
Abstract: Laser desorption followed by jet cooling has been used to produce an intense beam of internally cooled benzoic acid monomers. As a result, the SI So gas-phase absorption spectrum of the jet-cooled benzoic acid monomer could be identified for the first time. Delayed ionization out of a triplet state, populated by rapid SI T intersystem crossing, followed by mass-selective detection of the parent ions is performed. The spectral lines have a Lorentzian shape with a line width of 6.5 cm-I, corresponding to an intersystem crossing rate of 1.2 x s-I.

Journal ArticleDOI
TL;DR: It was found that the in vitro antioxidative activity of benzoic acid esters decreases with increasing chain length whereas the antipsoriatic activity increases, and Propyl gallate was found to be the most active OH scavenger.

Journal ArticleDOI
TL;DR: The crystal structures of 2-iodosyl-4-nitrobenzoate and 2-iodyl-5-methylbenzoic acid have been obtained as mentioned in this paper.
Abstract: The crystal structures of sodium 2-iodosyl-4-nitrobenzoate and sodium 2-iodyl-4-nitrobenzoate demonstrate a bicyclic structure for each, pKa, considerations indicate that the anions remain cyclized in solution. The crystal structure of 2-iodyl-5-methylbenzoic acid has also been obtained.

Patent
24 Aug 1990
TL;DR: A preservative for prods was proposed in this article, which consists of a conventional carrier or solvent, a three component mixt. phase consisting of (amts. based on the active ingredient) (a) 5-60 wt.% of an organic acid chosen from benzoic acid, 4-hydroxybenzoic aicd, salicyclic acid and/or dehydracetic acid or their Na, K, Ca, Mg, NH4 or ethanolamine salts.
Abstract: A preservative for prods. or systems with an aq. phase contains in a conventional carrier or solvent, a three component mixt. consisting of (amts. based on the active ingredient) (a) 5-60 wt.% of an organic acid chosen from benzoic acid, 4-hydroxybenzoic aicd, salicyclic acid, methanoic acid, ethanoic acid, propionic acid, sorbic acid, undecenoic acid and/or dehydracetic acid or their Na, K, Ca, Mg, NH4 or ethanolamine salts; (b) 10-95 wt.% of an alcohol of formula (I), (II) or (III); and (c) 0.1-20 wt.% of one or more poly(hexamethylene biguanide) salts of formula (IX). R1=H, n-alkyl, iso-alkyl or alkoxy each contg. 1-3C; R2 and R3=each H, Me or Et; n=3-4; m=4-6. x=hydrochloride, ethanoate, lactate, benzoate, propionate, 4-hydroxybenzoate, sorbate or salicylate. USE/ADVANTAGE - The preservative can be used in shampoos, cremes, lotions i.e. for cosmetic prods. with rinse-off and leave-on applications and for prods. used in washing and cleaning such as rinses and fabric softeners and in formulations for topical use of pharmaceuticals. The components act synergistically and have a broad spectrum of antimicrobial activity, even at low concns. The use of formaldehyde and other preservatives such as isothiazolinones which are environmentally polluting and toxic to humans is avoided.

Patent
25 Sep 1990
TL;DR: A natural deodorant composition containing glyceryl laurate, sorbic or benzoic acid and citric acid is described in this article, where the deodorants are described as:
Abstract: A natural deodorant composition containing glyceryl laurate, sorbic or benzoic acid and citric acid

Journal ArticleDOI
TL;DR: In this paper, the direct, catalytic carbonylation of aryl iodides to give the corresponding benzophenones is reported for the first time, under phase transfer conditions (aq. NaOH/C 6 H 6 /Bu 4 NBr) and under 1 atm pressure of carbon monoxide.

Journal ArticleDOI
TL;DR: Two prenylated benzoic acid derivatives isolated from the leaves of the Panamanian shrub Piper taboganum are significant repellents of the leafcutter ant Acromyrmex octospinosus at or below their apparent concentration in this plant, suggesting an effective natural defence against this insect pest.

Journal ArticleDOI
TL;DR: Three sulfate reducers oxidized benzaldehydes such as vanillin, 3,4,5-trimethoxybenzaldehyde, protocatechualdehyde, syringaldehyde, p-anisaldehyde, and 2-methoxy Benzaldehyde as electron donors for sulfate reduction and carbon dioxide and/or components of yeast extract as carbon sources for cell synthesis.
Abstract: Desulfovibrio vulgaris Marburg, "Desulfovibrio simplex" XVI, and Desulfovibrio sp. strain MP47 used benzaldehydes such as vanillin, 3,4,5-trimethoxybenzaldehyde, protocatechualdehyde, syringaldehyde, p-anisaldehyde, p-hydroxybenzaldehyde, and 2-methoxybenzaldehyde as electron donors for sulfate reduction and carbon dioxide and/or components of yeast extract as carbon sources for cell synthesis. The aldehydes were oxidized to their corresponding benzoic acids. The three sulfate reducers oxidized up to 7 mM vanillin and up to 4 mM p-anisaldehyde. Higher concentrations of vanillin or p-anisaldehyde were toxic. In addition, pyridoxal hydrochloride and o-vanillin served as electron donors for sulfate reduction. Salicylaldehyde, pyridine-2-aldehyde, pyridine-4-aldehyde, and 4-hydroxy-3-methoxybenzylalcohol were not oxidized. No molecular hydrogen was detected in the gas phase. The oxidized aldehydes were not further degraded.

Patent
16 Oct 1990
TL;DR: In this article, the authors describe a copolyester with repeat units, in which Ar denotes an aromatic and/or cycloaliphatic radical and Ar2 an aromatic radical.
Abstract: Thermotropic aromatic copolyesters containing repeat units and optionally in which Ar1 denotes an aromatic and/or cycloaliphatic radical and Ar2 an aromatic radical. They are obtained by polycondensation of p-(p-hydroxyphenoxy)benzoic acid, of an aromatic or cycloaliphatic diacid, of a diphenol and optionally of p-hydroxybenzoic acid.