Showing papers on "Benzoic acid published in 1973"
TL;DR: Two polyphenol oxidases from Bartlett pear peelings were purified to electrophoretic homogeneity according to polyacrylamide gel by a combination of Sephadex gel filtration, diethylaminoethyl cellulose chromatography and hydroxyl apatite chromatography, and Dependences of activity on oxygen and chlorogenic acid concentrations indicate a sequential mechanism for binding of these substrates to enzyme B.
Abstract: Two polyphenol oxidases (enzymes A and B) from Bartlett pear (Pyrus communis) peelings were purified to electrophoretic homogeneity according to polyacrylamide gel by a combination of Sephadex gel filtration, diethylaminoethyl cellulose chromatography and hydroxyl apatite chromatography. While the two enzymes differ electrophoretically at pH 9.3, chromatographically on hydroxyl apatite, and in the effect of ionic strength on activity, they are similar with respect to chromatography on diethylaminoethyl cellulose, substrate specificity, pH activity relations, inhibition by p-coumaric and benzoic acids, and heat stability. The two enzymes are o-diphenol oxidases with no detectable monophenolase or laccase activities. Pyrocatechol, 4-methyl catechol, chlorogenic acid, and d-catechin are good substrates of the enzymes with K(m) values in the range of 2 to 20 mm. Dependences of activity on oxygen and chlorogenic acid concentrations indicate a sequential mechanism for binding of these substrates to enzyme B. V(max) and K(m) values for oxygen and chlorogenic acid were 103 mumoles O(2) uptake per minute per milligram of enzyme, 0.11 mm and 7.2 mm, respectively, for enzyme B at pH 4.0. Both enzymes had maximum activity at pH 4.0 on chlorogenic acid. K(m) values for chlorogenic acid were independent of pH from 3 to 7; the V(max) values for both enzymes gave bell-shaped curves as a function of pH. p-Coumaric acid is a simple, linear noncompetitive inhibitor with respect to chlorogenic acid at pH 6.2 with K(i) values of 0.38 and 0.50 mm for enzymes A and B, respectively. Benzoic acid is a linear competitive inhibitor with respect to chlorogenic acid at pH 4.0 with K(i) values of 0.04 and 0.11 mm for enzymes A and B, respectively.
124 citations
TL;DR: The presence in the same reaction mixtures of either 4-hydroxy-2-oxovalerate or 2-hydroxypenta-2,4-dienoate was suggested by mass spectrometry and the degradative pathway of biphenyl is discussed.
Abstract: 1 2-Hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid was isolated and identified from washed suspensions of Pseudomonas putida incubated in the presence of 2,3-dihydroxybiphenyl 2 Benzoic acid was isolated from reaction mixtures of crude cell-free extracts incubated with 2,3-dihydroxybiphenyl 3 The presence in the same reaction mixtures of either 4-hydroxy-2-oxovalerate or 2-hydroxypenta-2,4-dienoate was suggested by mass spectrometry 4 The degradative pathway of biphenyl is discussed
88 citations
TL;DR: In this paper, a Calvet microcalorimeter has been used to determine the sublimation enthalpy of benzoic acid and anthracene, and the Gibbs energy functions for C6H5COOH and C14H10 gaseous molecules have been estimated.
Abstract: A Calvet microcalorimeter has been utilized to determine the sublimation enthalpy of benzoic acid and anthracene. The vapor pressures measured by Knudsen effusion weight‐loss method over the temperature ranges 338–383°K and 353–432°K were, respectively, log10p(torr)=(12.175 ± 0.047) − (4501 ± 17)/T, for benzoic acid, and log10p(torr)=(12.616 ± 0.062) − (5277 ± 24)/T, for anthracene. The Gibbs energy functions for C6H5COOH and C14H10 gaseous molecules have been estimated.
87 citations
TL;DR: The PCILO method accounts correctly for the preferred conformation of glyoxal, butadiene, benzaldehyde, benzoic acid, biphenyl and 2,2′-difluorobiphenyl as discussed by the authors.
79 citations
TL;DR: The interaction of substrates with a 4-methoxybenzoate O-demethylating enzyme system was studied by use of crude cell-free extracts and by the purified enzyme system, which requires NADH and oxygen as cofactors and acts on various substrates.
Abstract: The interaction of substrates with a 4-methoxybenzoate O-demethylating enzyme system was studied by use of crude cell-free extracts and also by the purified enzyme system. The two components of the enzyme system, an iron-containing flavoprotein and an iron-sulphur protein, were obtained in pure state from Pseudomonas putida grown on 4-methoxybenzoate as the sole carbon source. The purified enzyme system requires NADH and oxygen as cofactors and acts on various substrates. The highest affinity is found for 4-methoxybenzoate, but also N-methyl-4-aminobenzoate is demethylated and 4-alkylbenzoates are hydroxylated at the side chain. The enzyme is rather specific for para-substituted benzoic acid derivatives whereas 3-methoxybenzoate and 4-hydroxy-3-methoxybenzoate are demethylated slowly. The enzyme is also able to hydroxylate the aromatic ring. This is shown by the isolation of 3,4-dihydroxybenzoate as the hydroxylation product of 3-hydroxy- or 4-hydroxy-benzoate, respectively. Studies on substrate binding and oxygen consumption with substrate analogues showed an absolute requirement for the carboxy group at the aromatic ring. Benzoic acid derivatives without a suitable CH-bond uncouple oxygen uptake with a concomitant formation of hydrogen peroxide. Measurements of oxygen consumption indicate that the affinity towards oxygen is substrate dependent, probably due to steric alterations as a consequence of substrate binding.
57 citations
TL;DR: The chloroform extract of the heartwood of Pterocarpus santalinus yielded a mixture of red pigments which could be separated by polyamide column chromatography into two major compounds, Santalin-A and B, which gave the same permethyl ether, C38H36O10 which had 8 methoxyls and formed a number of derivatives typical of anhydrobenzopyranols as mentioned in this paper.
35 citations
TL;DR: Glutaminase A isolated from Escherichia coli reacts with the glutamine analogue, 6-diazo-5-oxonorleucine, in two ways: (a) it catalyzes hydrolysis of the C5—C6 bond to yield glutamic acid and diazomethane; and (b) a group at the active site of the enzyme becomes irreversibly alkylated by the intact carbon chain of the analogue.
34 citations
TL;DR: Comparison of kinetic data indicates that neither the type of sugar-aglycone linkage, nor the aglycone structure alone can explain the observed K(m) and V(max.) values.
Abstract: 1. The relative rates of hydrolysis of synthetically prepared beta-d-glucuronic esters [aglycone: benzoic acid, veratroic (3,4-dimethoxybenzoic) acid, indol-3-ylacetic acid and ethylbutyric acid], and beta-d-glucuronic ethers (aglycone: phenolphthalein, p-nitrophenol, 3,4-dimethoxyphenol, 3,4-dimethoxybenzyl alcohol) by commercial preparations of beta-glucuronidase from bovine liver and Escherichia coli were investigated. The rates of hydrolysis of all compounds tested were followed by measuring the formation of glucuronic acid under conditions which do not affect the glycosidic ester bond. 2. The pH profiles of the substrates in reaction with the enzyme from both sources were determined, and substrate-saturation curves at the optimal pH for each substrate were constructed; double-reciprocal plots of activity against concentration were linear. 3. Comparison of kinetic data indicates that neither the type of sugar-aglycone linkage, nor the aglycone structure alone can explain the observed K(m) and V(max.) values. 4. alpha-d-Glucuronic esters of benzoic and veratroic acid resisted hydrolysis by beta-glucuronidase from both sources.
26 citations
TL;DR: Incubation of quinic acid with rat caecal microorganisms resulted in the formation of benzoic acid under aerobic and anaerobic conditions and small amounts of protocatechuic acid were detected when aerobic conditions were employed.
Abstract: 1. Hippuric acid (12·3% of the dose) and catechol (1·0% of the dose) were found as urinary metabolites when (-)-quinic acid (100 mg) was administered orally to rats. Neither protocatechuic acid nor vanillic acid was detected.2. No significant differences in the extent of urinary excretion of hippuric acid and catechol were found when the quinic acid was given at the end of two successive 24-day periods during which the rats were fed a purified diet containing 1% quinic acid.3. Incubation of quinic acid with rat caecal microorganisms resulted in the formation of benzoic acid under aerobic and anaerobic conditions. Catechol was not found in these incubates but small amounts of protocatechuic acid were detected when aerobic conditions were employed.
20 citations
18 citations
TL;DR: In vitro tests showed that the increase in toxicity of benzoic acid to N. galligena obtained by the addition of sap expressed from healthy apples decreased with increasing Fruit maturity, and the slight increase in sap pH observed with increasing fruit maturity was insufficient to account for this change.
Abstract: Apples, cv. Bramley's Seedling, were picked and inoculated with Nectria galligena at various dates in two consecutive growing seasons. The concentrations of benzoic acid present in infected tissues 10 days after inoculation were highest in apples picked approximately 100 days after full blossom (late August to early September) in both years. The rate of production of benzoic acid was also greatest at that time. The maximum concentration of benzoic acid accumulated in apples of any age was independent of the numbers of conidia in the inoculum, but the time taken to reach the maximum decreased with increasing spore numbers. The concentrations of benzoic acid which accumulated after inoculation of various parts of apples were determined. Most benzoic acid was found in the cortical tissues adjacent to the core in apples picked 56 days after full blossom; in later picks the highest concentrations were found in the middle of the cortex. Similar concentrations of benzoic acid accumulated in inoculated slices of equal thickness cut from both the stem and calyx end of fruit, but the concentration decreased with decreasing slice thickness. In vitro tests showed that the increase in toxicity of benzoic acid to N. galligena obtained by the addition of sap expressed from healthy apples decreased with increasing fruit maturity. The slight increase in sap pH observed with increasing fruit maturity was insufficient to account for this change.
TL;DR: In this article, it was shown that the excess energy of the benzoyl cation can be accounted for by an electronic excited state of the ion in the mass spectra of benzoic acid, benzaldehyde, benzamide, methyl benzoate and possibly benzophenone.
Abstract: The heat of formation of the benzoyl cation generated from [C6H5COX]+˙ is found to depend on X, while the heat of formation of the phenyl ion produced therefrom is, with one exception, independent of X. The excess energy of the benzoyl cation can be accounted for by an electronic excited state of the ion in the mass spectra of benzoic acid, benzaldehyde, benzamide, methyl benzoate and possibly benzophenone; the benzoyl cation is not excited in the mass spectra of acetophenone and benzoyl chloride.
TL;DR: Autoxidation of 3,4′-dihydroxyflavone in dimethylformamide in the presence of potassium t-butoxide results in oxidative cleavage of the hetrocyclic ring to give 2-(4-hydroxybenzoyloxy) benzoic acid and carbon monoxide in excellent yields; this provides a nonenzymic model for the reaction of quercetinas.
Abstract: Autoxidation of 3,4′-dihydroxyflavone in dimethylformamide in the presence of potassium t-butoxide results in oxidative cleavage of the hetrocyclic ring to give 2-(4-hydroxybenzoyloxy) benzoic acid and carbon monoxide in excellent yields; this provides a nonenzymic model for the reaction of quercetinas.
TL;DR: In this paper, a method for the thermometric titration of organic acids in non-aqueous solution, involving the ionic polymerisation of acrylonitrile to indicate the end-point, has been evaluated for a range of mono- and polyacidic compounds, including phenols, triazine derivatives and tannic acid.
Abstract: A method for the thermometric titration of organic acids in non-aqueous solution, involving the ionic polymerisation of acrylonitrile to indicate the end-point, has been evaluated for a range of mono- and polyacidic compounds, including phenols, triazine derivatives and tannic acid. In addition to acrylonitrile, methyl acrylate and dimethyl itaconate can be used as monomers for the end-point indication. A number of titrant-catalysts have been examined, including tetra-n-butylammonium hydroxide, n-butyllithium and potassium hydroxide.The precision of the method ranges from about 0·5 per cent. with 0·1 M titrant, to 2·7 per cent., with 0·001 M titrant, by using the manual and semi-automatic methods described in Part I.Sample sizes down to about 0·0001 mequiv, e.g., about 10 µg of benzoic acid, which corresponds to 100 p.p.m. of benzoic acid in the volumes of sample solution titrated, can be determined with 0·001 M titrant. Calibration graphs show the volume of titrant and mass of sample to be linearly or almost linearly related in the range 0 to 2 ml of titrant.Comparison of the titration values obtained by using the acetone method and ionic polymerisation with potassium hydroxide and tetra-n-butylammonium hydroxide solutions as titrants enables one to differentiate between acidic groups of different ionic strengths in the 10 to 12 pKa region.
01 Jan 1973
TL;DR: Two polyphenol oxidases from Bartlett pear peelings were purified to electrophoretic homogeneity according to polyacrylamide gel by a combination of Sephadex gel filtration, diethylaminoethyl cellulose chromatography and hydroxyl apatite chromatography, and Dependences of activity on oxygen and chlorogenic acid concentrations indicate a sequential mechanism for binding of these substrates to enzyme B.
Abstract: Two polyphenol oxidases (enzymes A and B) from Bartlett pear (Pyrus communis) peelings were purified to electrophoretic homogeneity according to polyacrylamide gel by a combination of Sephadex gel filtration, diethylaminoethyl cellulose chromatography and hydroxyl apatite chromatography. While the two enzymes differ electrophoretically at pH 9.3, chromatographically on hydroxyl apatite, and in the effect of ionic strength on activity, they are similar with respect to chromatography on diethylaminoethyl cellulose, substrate specificity, pH activity relations, inhibition by p-coumaric and benzoic acids, and heat stability. The two enzymes are o-diphenol oxidases with no detectable monophenolase or laccase activities. Pyrocatechol, 4-methyl catechol, chlorogenic acid, and d-catechin are good substrates of the enzymes with Km values in the range of 2 to 20 mM. Dependences of activity on oxygen and chlorogenic acid concentrations indicate a sequential mechanism for binding of these substrates to enzyme B. Vmax and Km values for oxygen and chlorogenic acid were 103 ,umoles 02 uptake per minute per milligram of enzyme, 0.11 mM and 7.2 mM, respectively, for enzyme B at pH 4.0. Both enzymes had maximum activity at pH 4.0 on chlorogenic acid. K., values for chlorogenic acid were independent of pH from 3 to 7; the Vmax values for both enzymes gave bell-shaped curves as a function of pH. p-Coumaric acid is a simple, linear noncompetitive inhibitor with respect to chlorogenic acid at pH 6.2 with K, values of 0.38 and 0.50 mM for enzymes A and B, respectively. Benzoic acid is a linear competitive inhibitor with respect to chlorogenic acid at pH 4.0 with K, values of 0.04 and 0.11 mM for enzymes A and B, respectively.
TL;DR: In this paper, it was shown that α-β unsaturated aliphatic and aromatic esters give only low yields of ketonic enolates and that the low enolization of the intermediate ketones by these alkylmagnesium halides can explain this result.
TL;DR: In this article, the u.v. spectra of 12 halogen-substituted benzoic acid hydrazides were obtained spectrophotometrically and the influence of the nature and the position of the halogen atom on the pK values was discussed.
Abstract: The u.v. spectra of 12 halogen-substituted benzoic acid hydrazides are reported. A very intense band in the region 225–260 mμ and a second one of low intensity at 270–290 mμ are assigned to π → π* and n → π* transitions, respectively.The pK1 and pK2 of the mentioned hydrazides, corresponding to the Bronsted acids and XC6H4C(OH)=NNH2 respectively, were obtained spectrophotometrically (X = F, Cl, Br, or I in o-, m-, and p-position). The influence of the nature and the position of the halogen atom on the pK values is discussed.
Patent•
05 Jan 1973TL;DR: In this paper, the solid-state disproportionation of potassium benzoate to dipotassium terephthalate and benzene using zinc benzosate catalyst is conducted with the solid reagents dispersed as a slurry in liquid terphenyl diluent.
Abstract: The solid-state disproportionation of potassium benzoate to dipotassium terephthalate and benzene using zinc benzoate catalyst is conducted with the solid reagents dispersed as a slurry in liquid terphenyl diluent. The reactor effluent is water-quenched to obtain a liquid terphenyl phase, a water phase containing dissolved phthalates, and solid spent zinc oxide catalyst. The catalyst is separated by filtration, reslurried in terphenyl, reacted with benzoic acid to regenerate zinc benzoate, and the resultant catalyst slurry recycled to the reactor. The solids-free aqueous phase is contacted with benzoic acid to precipitate terephthalic acid crystals and form soluble potassium benzoate. The crystals are separated by filtration and recovered as a product of the process. The aqueous potassium benzoate solution is concentrated by evaporation and then contacted with hot terphenyl to produce a slurry of solid potassium benzoate in terphenyl for recycle to the reactor. Byproduct benzene is vented from the reactor and/or the effluent quench step.
TL;DR: In this article, the electronic spectra of nitrobenzene and benzoic acid were analyzed using the CNDO/2 method (del Bene and Jaffe's version).
TL;DR: In this paper, the photochemical reaction of α-nitroepoxides showed marked solvent dependence, and the effects of acidity and hydrogen-donating property of solvents on the excited α-nodes were interpreted in terms of effects of the acidity.
Abstract: The photochemical reaction of α-nitroepoxides showed marked solvent dependence. The photolysis of (1,2-epoxy-2-nitropropyl)benzene (I) in 2-propanol led to the formation of three products 1-phenyl-1-isopropoxy-2-propanone (IIb), 1-phenyl-1,2-propanedione oxime (III) and 1-hydroxy-1-phenyl-2-propanone oxime (IV), whereas on irradiation in ether I gave exclusively IV. However, in t-butyl alcohol, benzene, acetone, acetonitrile or n-hexane, I was not susceptible to photolysis. The photolysis of α,α′-epoxy-α-nitrobibenzyl (V) in ether gave benzoin oxime (VII) in addition to benzaldehyde and benzoic acid, whereas in methanol it gave benzoin methyl ether (VI) in the dark. These reactions are interpreted in terms of effects of the acidity and hydrogen-donating property of solvents on the excited α-nitroepoxides. The pyrolysis of I and V were also examined.
TL;DR: It is found that II competitively inhibits the binding of I at all concentration levels of the inhibitor, and the conclusion is reached that II affects the nature of the I binding site rather than the number of molecules bound.
TL;DR: Hippuric acid can be determined, after conversion to its methyl ester with diazomethane, by gas chromatography on cyclohexane dimethanol succinate as discussed by the authors.
Patent•
06 Sep 1973TL;DR: A LUBRICATING GREASE COMPOSITION COMPRISING A MAJOR PROPORTION of a MINERAL LUBRICATING OIL BASE HAVING AN ANILINE POINT BELOW 230*F.
Abstract: 1. A LUBRICATING GREASE COMPOSITION COMPRISING A MAJOR PROPORTION OF A MINERAL LUBRICATING OIL BASE HAVING AN ANILINE POINT BELOW ABOUT 230*F. THICKENED TO THE CONSISTENCY OF A GREASE WITH AN ALUMINUM COMPLEX SOAP OF BENZOIC ACID AND A SATURATED FATTY ACID HAVING FROM 20 TO 22 CARBON ATOMS PER MOLECULE WHEREIN THE MOLAR RATIO OF BENZOIC ACID TO C20-C22 FATTY ACID IS ABOUT 1.25:1 TO ABOUT 2:1, BENZOIC ACID TO C20-C22 FATTY ACID, RESPECTIVELY, AND A SMALL AMOUNT, SUFFICIENT TO IMPROVE THE ANTIWEAR AND EXTREME PRESSURE PROPERTIES OF THE GREASE, OF PRECIPITATED CALCIUM CARBONATE.
TL;DR: The anodic oxidation of benzoic acid in acetonitrile and propionitrile was studied in this article, where the anodic oxidization gave N-acetylanthranilic acid, N-propionylbenzamide, and dipropionylamine.
Abstract: The anodic oxidation of benzoic acid in acetonitrile and propionitrile was studied. Electrolysis was employed under a controlled potential or current. Benzoic acid was changed into an intermediate benzoyloxy radical through de-electronation in acetonitrile, and the resulting radical was reacted with acetonitrile to give N-acetylanthranilic acid in a 38% yield under constant potential electrolysis. In propionitrile, the anodic oxidation gave N-propionylanthranilic acid, N-propionylbenzamide, and dipropionylamine. No Kolbe-type reaction was observed.
TL;DR: The rate and products of the reaction between each of a range of deactivated substituted benzenes and the tri-iodine cation, in sulphuric acid solution, have been investigated and the kinetic isotope effect for the iodination of benzoic acid was found to be kH/kD= 2.
Abstract: The rate and products of the reaction between each of a range of deactivated substituted benzenes and the tri-iodine cation, in sulphuric acid solution, have been investigated. The rate constants may be correlated by the electrophilic substituent constants σ+ giving a value for the reaction constant ρ=–6·4. The kinetic isotope effect for the iodination of benzoic acid was found to be kH/kD= 2. Further details of the solvent effect are reported.
TL;DR: In this paper, it was shown that β-diketone can reversibly react with acyl chloride to form new β diketones by way of the mixed triacylmethanes.
Abstract: The treatment of acetylacetone (I) with n-butyryl chloride in the presence of aluminum chloride in nitrobenzene gave n-butyrylacetone and di-n-butyrylmethane at 45°C. The same products were obtained, along with n-butyric acid, when n-butyrylacetone or di-n-butyrylmethane was treated with acetyl chloride under analogous conditions. The reactions between I and benzoyl chloride and between benzoylacetone or dibenzoylmethane and acetyl chloride gave products consisting of I, benzoylacetone, dibenzoyl-, diacetylbenzoyl-, acetyldibenzoyl-, tribenzoyl-methane, and benzoic acid. These findings show that β-diketone can reversibly react with acyl chloride to form new β-diketones by way of the mixed triacylmethanes. The acylation mechanism is discussed.
TL;DR: In this paper, the mass spectra of benzoic acid derivatives have been used to determine the doubly charged ion mass spectras of a series of derivatives, and a general feature of all spectra is the presence of pronounced M-CO species.
Abstract: The technique of Beynon1,2 has been used to determine the ?doubly charged ion? mass spectra of a series of benzoic acid derivatives. A general feature of all spectra is the presence of pronounced M-CO species. The losses of carbon monoxide from the doubly charged molecular ions of m- amino- and m-hydroxy-benzoic acids originate mainly from the carboxyl groups, whereas the predominant loss from benzoic acid involves the aryl ring system. The spectra of anthranilates and salicylates contain peaks produced by characteristic proximity effects.
TL;DR: Indian fruit bats (Pteropus giganteus) do not convert injected [14C] benzoic acid into hippuric acid, and the main urinary metabolite in the fruit bat was benzoylglucuronide.
TL;DR: The time course of disappearance from plasma in all three species suggests enterohepatic circulation and the principal excretion product in rat urine has been identified as 2-mercapto-5-trifluoromethylbenzoic acid arising via S-dealkylation.
Abstract: 1. Benzylthio-5-trifluoromethylbenzoic acid (BTBA) is well absorbed by rat, dog and man. The time course of disappearance from plasma in all three species suggests enterohepatic circulation.2. The principal excretion product in rat urine has been identified as 2-mercapto-5-trifluoromethylbenzoic acid arising via S-dealkylation.3. 2-Mercapto-5-trifluoromethylbenzoic acid is also converted to the disulphide metabolite, [2,2′-dithiobis(5-trifluoromethyl)benzoic acid], which is secreted together with BTBA and their glucuronide conjugates in rat bile. Rapid hydrolysis in the intestine results in faecal elimination of largely free BTBA and disulphide metabolite (2,2′-dithiobis[5-trifluoromethyl]benzoic acid).4. In man, approximately 50% of the dose is recovered from urine as amino-acid and glucuronide conjugates of the drug and its debenzyl metabolite (2-mercapto-5-trifluoromethylbenzoic acid).5. The drug is not readily metabolized by the dog and is secreted with bile and eliminated unchanged with faeces.