Ortho-substituted Benzoates Research Articles

Coordination Modes of Ortho-Substituted Benzoates Towards Divalent Copper Centres in the Presence of Diimines

The coordination modes of several ortho-substituted benzoates towards the copper(II) centre are investigated. The coordination environment of the metal ion includes nitrogen atoms from 2,2′-bipyridine (bipy) or 1,10-phenanthroline (phen) and occasionally oxygen atoms from coordinated water, ethanol molecules, or nitrate ions. The compounds are investigated by a variety of spectroscopic methods and by single-crystal X-ray diffraction. Although the reaction scheme involved equimolar amounts of the reactants, cationic dinuclear compounds with a metal/benzoate/diimine ratio of 2:3:2 have been realized, cationic in nature regardless of the counter anion used. Furthermore, the carboxylate moieties display a range of twisting relative to the orientation of the benzene ring to which they are attached.

Spectroscopic Study on Aqueous Uranyl(VI) Complexes with Methoxy- and Methylbenzoates: Electronic and Steric Effects of the Substituents

Aqueous complexation of uranyl(VI) ions with methoxy- and methylbenzoates in 0.1 M NaClO4 solutions was studied by means of UV-vis absorption and Raman spectroscopy. The predominance of 1:1 complexation (uranyl to ligand) was verified for all uranyl carboxylates under acidic conditions (-log [H+] < 3.2), and absorption spectra, stability constants, and symmetric stretching frequencies of the uranyl group of the complexes were determined for the first time. For meta- and para-substituted benzoates, a linear free energy relationship (LFER) was observed between the equilibrium constants for the protonation (log βP) and uranyl complexation (log βU) reactions, and the electronic effects of the substituents were successfully described by the Hammett equation. In the case of ortho-substituted benzoates, the stability constant of uranyl 2-methoxybenzoate is slightly lower than the LFER trend, which is generally explained by the destabilization of cross-conjugation in the uranyl complex due to the steric hindrance between the reaction center and adjacent methoxy group. On the contrary, the stability constant of uranyl 2-methylbenzoate is comparable to the LFER trend, implying that the steric effect is relatively insignificant for the smaller methyl group. The utility of such thermodynamic correlations between the uranyl-substituted benzoates is useful for the molecular understanding and predictive modeling of chemical interactions between actinyl(VI) ions and various organic carboxyl groups.

Toluene dioxygenase mediated oxidation of halogen-substituted benzoate esters

A series of ortho-, meta-, and para- halogen-substituted methyl benzoate esters was subjected to enzymatic dihydroxylation via the whole-cell fermentation with E. coli JM109 (pDTG601A). Only ortho-substituted benzoates were metabolized. Methyl 2-fluorobenzoate yielded one diol regioselectively whereas methyl 2-chloro-, methyl 2-bromo- and methyl 2-iodobenzoates each yielded a mixture of regioisomers. Absolute stereochemistry was determined for all new metabolites. Computational analysis of these results and a possible rationale for the regioselectivity of the enzymatic dihydroxylation is advanced.

Decarboxylative Biaryl Synthesis from Aromatic Carboxylates and Aryl Triflates

A new catalyst system, generated in situ from Cu2O, 1,10-phenanthroline, PdI2, and Tol-BINAP, for the first time allows the decarboxylative coupling of carboxylic acids with aryl triflates. In contrast to previous decarboxylative couplings that remained limited to certain activated carboxylates, e.g., ortho-substituted benzoates, this halide-free protocol is generally applicable to aromatic carboxylic acid salts regardless of their substitution pattern.

Liquid crystalline properties of some compounds having a perfluoroalkyl group

The paper describes the liquid crystalline properties of 2-( n-perfluoroalkyl)ethyl para-, meta-, and/or ortho-substituted benzoates, and some related compounds. Most of the ortho and/or meta-substituted derivatives show a smectic B phase, while the para-substituted ones are non-mesogenic. When the substituent is a nitro or a cyano group, many derivatives show a smectic A, as well as a B phase. The corresponding 4- trans-alkylcyclohexanecarboxylates are non-mesogenic. Meta- or para-substituted phenyl ω-hydroperfluoroalkanoates are also non-mesogenic. From these results, we conclude that in order to show liquid crystalline properties for the present systems, the substituents at meta and/or ortho positions, orientation of the ester group, and the rigid perfluoroalkyl group are very important. X-ray study indicated that the smectic A and B phases for polar liquid crystals have a partially bilayer and bilayer arrangements, respectively. The smectic B phase for non-polar liquid crystals have a monolayer arrangement. Thermal motion around the perfluoroalkyl group is assumed to be almost frozen in both phases.

Metabolism of and inhibition by chlorobenzoates in Pseudomonas putida P111

Pseudomonas putida P111 was isolated by enrichment culture on 2,5-dichlorobenzoate and was also able to grow on 2-chloro-, 3-chloro-, 4-chloro-, 2,3-dichloro-, 2,4-dichloro-, and 2,3,5-trichlorobenzoates. However, 3,5-dichlorobenzoate completely inhibited growth of P111 on all ortho-substituted benzoates that were tested. When 3,5-dichlorobenzoate was added as a cosubstrate with either 3- or 4-chlorobenzoate, cell yields and chloride release were greater than those observed from growth on either monochlorobenzoate alone. Moreover, resting cells of P111 grown on 4-chlorobenzoate released chloride from 3,5-dichlorobenzoate and produced no identifiable intermediate. In contrast, resting cells grown on 2,5-dichlorobenzoate metabolized 3,5-dichlorobenzoate without release of chloride and accumulated a degradation product, which was identified as 1-carboxy-1,2-dihydroxy-3,5-dichlorocyclohexadiene on the basis of gas chromatography-mass spectrometry confirmation of its two acid-hydrolyzed products, 3,5- and 2,4-dichlorophenol. Since 3,5-dichlorocatechol was rapidly metabolized by cells grown on 2,5-dichlorobenzoate, it is apparent that 1-carboxy-1,2-dihydroxy-3,5-dichlorocyclohexadiene is not further metabolized by these cells. Moreover, induction of a functional dihyrodiol dehydrogenase would not be required for growth of P111 on other ortho-chlorobenzoates since the corresponding chlorodihydrodiols produced from a 1,2-dioxygenase attack would spontaneously decompose to the corresponding catechols. In contrast, growth on 3-chloro-, 4-chloro-, or 3,5-dichlorobenzoate requires a functional dihydrodiol dehydrogenase, yet only the two monochlorobenzoates appear to induce for it.

Degradation of 2-bromo-, 2-chloro- and 2-fluorobenzoate by Pseudomonas putida CLB 250.

Pseudomonas putida strain CLB 250 (DSM 5232) utilized 2-bromo-, 2-chloro- and 2-fluorobenzoate as sole source of carbon and energy. Degradation is suggested to be initiated by a dioxygenase liberating halide in the first catabolic step. After decarboxylation and rearomatization catechol is produced as a central metabolite which is degraded via the ortho-pathway. After inhibition of ring cleavage activities with 3-chlorocatechol, 2-chlorobenzoate was transformed to catechol in nearly stoichiometric amounts. Other ortho-substituted benzoates like anthranilate and 2-methoxybenzoate seem to be metabolized via the same route.

Degradation of 2-bromo-, 2-chloro- and 2-fluorobenzoate byPseudomonas putidaCLB 250

Pseudomonas putida strain CLB 250 (DSM 5232) utilized 2-bromo-, 2-chloro- and 2-fluorobenzoate as sole source of carbon and energy. Degradation is suggested to be initiated by a dioxygenase liberating halide in the first catabolic step. After decarboxylation and rearomatization catechol is produced as a central metabolite which is degraded via the ortho-pathway. After inhibition of ring cleavage activities with 3-chlorocatechol, 2-chlorobenzoate was transformed to catechol in nearly stoichiometric amounts. Other ortho-substituted benzoates like anthranilate and 2-methoxybenzoate seem to be metabolized via the same route.

Nature of the ortho effect. III. Acid hydrolysis of ortho-substituted benzoates and esterification of ortho-substituted benzoic acids

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNature of the ortho effect. III. Acid hydrolysis of ortho-substituted benzoates and esterification of ortho-substituted benzoic acidsMarvin ChartonCite this: J. Am. Chem. Soc. 1969, 91, 3, 619–623Publication Date (Print):January 1, 1969Publication History Published online1 May 2002Published inissue 1 January 1969https://doi.org/10.1021/ja01031a017RIGHTS & PERMISSIONSArticle Views153Altmetric-Citations27LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (459 KB) Get e-Alerts Get e-Alerts

Nature of the ortho effect. IV. Alkaline hydrolysis of ortho-substituted benzoates

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNature of the ortho effect. IV. Alkaline hydrolysis of ortho-substituted benzoatesMarvin ChartonCite this: J. Am. Chem. Soc. 1969, 91, 3, 624–628Publication Date (Print):January 1, 1969Publication History Published online1 May 2002Published inissue 1 January 1969https://doi.org/10.1021/ja01031a018RIGHTS & PERMISSIONSArticle Views138Altmetric-Citations28LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (487 KB) Get e-Alerts Get e-Alerts

THE TRANSMISSION OF POLAR EFFECTS: PART III. THE KINETICS OF THE ACID-CATALYZED ESTERIFICATION OF 3-SUBSTITUTED ACRYLIC ACIDS AND THE ALKALINE HYDROLYSIS OF THE METHYL ESTERS

The rate coefficients for the acid-catalyzed esterification in methanol at 35.0° of fourteen 3-substituted acrylic acids have been determined. Rate coefficients have also been determined for the alkaline hydrolysis in 70% v/v dioxin–water at 18.8° of 13 methyl esters and the carbonyl-stretching frequencies of the esters have been examined. The effect of trans-substitution is assessed by use of the Hammett equation. In the alkaline hydrolysis, the transmission of polar effects is approximately 1.9 that of the meta- and para-substituted benzoates. An analysis of the steric effects in the cis-isomers in both reactions shows that the steric effects of the halogeno-substituents in the two reactions differ and an explanation is offered. The application of the Taft–Ingold equation to ortho-substituted benzoates is criticized. The carbonyl-stretching frequencies of the cis-halogeno-esters exhibit a shift of +8 cm−1 compared with the trans-isomers; this shift is attributed to an electrostatic effect.