The kinetics of the reactions of 2-substituted nicotinic acids with diazodiphenylmethane in various alcohols

The rate constants of 2-substituted nicotinic acids in reaction with diazodiphenylmethane (DDM) in eight alcohols at 30 ?C have been determined. In order to explain the obtained results through solvent effects, the second order reaction rate constants (k) of the examined acids were correlated using the appropriate solvent parameters by the equation: logk=logk0 af(?) + b?* + cn?H where f(?) is the measure of solvent ability as a dielectric to stabilize the separation of opposite charges in the activated complex, ?* is the measure of solvent ability to stabilize proton in the initial state and n?H represents the ability of protic solvents to form hydrogen bond with the negative end of the ion-pair intermediate. These constants were correlated also by using solvatochromic equation of the form logk=logk0 + s?* + a? + b? where ?* is the measure of the solvent polarity, ? represents the scale of the solvent hydrogen bond donor acidities (HBD) and ? represents the scale of the solvent hydrogen bond acceptor basicities (HBA). The correlations of the kinetic data were carried out by means of multiple linear regression analysis. The results obtained for 2-substituted nicotinic acids were compared with the results for ortho-substituted benzoic acid under the same experimental conditions.

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The reactivity of α,β-unsaturated carboxylic acids. Part XVI. The kinetics of the reaction of cycloalkenecarboxylic and cycloalkenylacetic acids with diazodiphenylmethane in various alcohols

Journal of the Serbian Chemical Society ◽

10.2298/jsc0202077u ◽

2002 ◽

Vol 67 (2) ◽

pp. 77-85 ◽

Cited By ~ 7

Author(s):

Gordana Uscumlic ◽

Jasmina Nikolic ◽

Vera Krstic

Keyword(s):

Hydrogen Bond ◽

Rate Constants ◽

Kinetic Data ◽

Linear Regression Analysis ◽

Spectroscopic Method ◽

Solvent Polarity ◽

Multiple Linear Regression Analysis ◽

Hydrogen Bond Donor ◽

Experimental Conditions ◽

Hydrogen Bond Acceptor

The rate constants for the reaction of diazodiphenylmethane with 1-cyclopentenecarboxylic, 1-cycloheptenecarboxylic, cyclopent-1-enylacetic and cyclohept-1-enylacetic acids were determined in eight alcohols at 30 ?C using the appropriate UV-spectroscopic method. In order to explain the kinetic results through solvent effects, the second order rate constants of the examined acids were correlated using a total solvatochromic equation, of the form: log k = A0+ s?*+a??+ b?, where ?* is a measure of the solvent polarity, ??represents the scale of solvent hydrogen bond acceptor basicities and ? represents the scale of solvent hydrogen bond donor acidities. The correlations of the kinetic data were carried out by means of multiple linear regression analysis. The opposite sings of the electrophilic and the nucleophilic parameters are in agreement with the well-known reaction mechanism. The results presented in this paper were compared with the kinetic data for 1-cyclohexenecarboxylic and cyclohex-1-enylacetic acids obtained under the same experimental conditions.

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The influence of the solvent on organic reactivity. Part II. Hydroxylic solvent effects on the reaction rates of diazodiphenylmethane with 2-(2-substituted cyclohex-1-enyl)acetic and 2-(2-substituted

Journal of the Serbian Chemical Society ◽

10.2298/jsc0409601n ◽

2004 ◽

Vol 69 (8-9) ◽

pp. 601-610 ◽

Cited By ~ 4

Author(s):

Jasmina Nikolic ◽

Gordana Uscumlic ◽

Vera Krstic

Keyword(s):

Hydrogen Bond ◽

Solvent Effects ◽

Linear Regression Analysis ◽

Solvent Polarity ◽

Multiple Linear Regression Analysis ◽

Reaction Rates ◽

Hydrogen Bond Donor ◽

Initial State ◽

Hydrogen Bond Acceptor ◽

Acetic Acids

The rate constants for the reaction of diazodiphenylmethane with 2-(2-substituted cyclohex-1-enyl)acetic acids and 2-(2-substituted phenyl)acetic acids, previously determined in seven hydroxylic solvents, were correlated using the total solvatochromic equation, of the form logk = logk0 + s?*+ a? + b?, the two-parameter model, logk=logk0 + s?*+ a? and a single parameter model logk = logk0 + b?, where ?*is a measure of the solvent polarity, ? represents the scale of solvent hydrogen bond acceptor basicities and ? represents the scale of solvent hydrogen bond donor acidities. The correlations of the kinetic data were carried out by means of multiple linear regression analysis and the solvent effects on the reaction rates were analyzed in terms of initial state and transition state contributions.

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Solvent effect on electronic absorption spectra of cyclohex-1-enylcarboxylic and 2-methylcyclohex-1-enylcarboxylic acids

Journal of the Serbian Chemical Society ◽

10.2298/jsc0006353n ◽

2000 ◽

Vol 65 (5-6) ◽

pp. 353-359 ◽

Cited By ~ 1

Author(s):

Jasmina Nikolic ◽

Gordana Uscumlic ◽

Vera Krstic

Keyword(s):

Hydrogen Bond ◽

Absorption Spectra ◽

Electronic Absorption Spectra ◽

Linear Regression Analysis ◽

Solvent Polarity ◽

Multiple Linear Regression Analysis ◽

Ultraviolet Absorption ◽

Aprotic Solvents ◽

Hydrogen Bond Donor ◽

Hydrogen Bond Acceptor

The ultraviolet absorption spectra of cyclohex-1-enylcarboxylic acid and 2- methylcyclohex-1-enylcarboxylic acid were determined in six protic and nine aprotic solvents in the wavelength range from 200 to 400 nm. The position of the ?max of the two examined acids showed that the ultraviolet absorption maximums of cyclohex-1-enylcarboxylic acid were at consistently longer wavelengths in protic solvents than those of methylcyclohex-1-enylcarboxylic acid. The opposite was true in aprotic solvents. In order to explain the obtained results, the ultraviolet absorption frequencies of the electronic transitions in the carboxy carbonyl group of the examined acids were correlated using a total solvatochromic equation of the form: v = v0 + s?* + a? + b?, where ?* is a measure of the solvent polarity, ? represents the scale of solvent hydrogen bond acceptor basicities and a represents the scale of solvent hydrogen bond donor acidities. The correlation of the spectroscopic data was carried out by means of multiple linear regression analysis. The opposing solvent effects on the ultraviolet absorption maximums of the two examined acids were discussed.

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Solvent effect on electronic absorption spectra of some 2-aminobenzimidazoles

Acta periodica technologica ◽

10.2298/apt0233093p ◽

2002 ◽

pp. 93-99

Author(s):

Nada Perusic-Janjic ◽

Jevrem Janjic ◽

Sanja Podunavac-Kuzmanovic

Keyword(s):

Hydrogen Bond ◽

Electronic Absorption Spectra ◽

Linear Regression Analysis ◽

Solvent Polarity ◽

Multiple Linear Regression Analysis ◽

Proton Donor ◽

Proton Acceptor ◽

Aprotic Solvents ◽

Hydrogen Bond Donor ◽

Hydrogen Bond Acceptor

The effect of protic and aprotic solvents on electronic apsorption spectra of 1-(3-X-benzil)-2-aminobenzimidazoles (X=CH3;OCH3; Cl) was examined. UV-apsorption spectra (200-400 nm) were recorded in five protic and four aprotic solvents. Batochromic shift of absorption maxima, ?max, occurs from the solvent with the highest proton-donor ability to the proton acceptor solvent (from water to DMSO). Positions of absortion maxima in various solvents are in correlation with the dielectric constant of the solvent. In order to explain the obtained results, the ultraviolet absorption frequences of the electronic transitions of the compounds were correlated using a total solvatochromic equation of the form: ?max = ?0 + s?* + a? + b?, where??* is the measure of solvent polarity. Prepresents the scale of solvent hydrogen bond acceptor basicities and ? represents the scale of solvent hydrogen bond donor acidities. Correlation of spectroscopic data was carried out by means of multiple linear regression analysis.

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Reactivity of cyclohex-1-enylcarboxylic and 2-methylcyclohex-1-enylcarboxylic acids with diazodiphenylmethane in aprotic solvents

Journal of the Serbian Chemical Society ◽

10.2298/jsc0012839n ◽

2000 ◽

Vol 65 (12) ◽

pp. 839-846

Author(s):

Jasmina Nikolic ◽

Gordana Uscumlic ◽

Vera Krstic

Keyword(s):

Hydrogen Bond ◽

Rate Constants ◽

Kinetic Data ◽

Linear Regression Analysis ◽

Spectroscopic Method ◽

Reaction Rates ◽

Aprotic Solvents ◽

Experimental Conditions ◽

Hydrogen Bond Acceptor ◽

Protic Solvents

Rate constants for the reaction of diazodiphenylmethane with cyclohex-1-enylcarboxylic acid and 2-methylcyclohex-1-enylcarboxylic acid were determined in nine aprotic solvents, as well as in seven protic solvents, at 30?C using the appropriate UV-spectroscopic method. In protic solvents the unsubsituted acid displayed higher reaction rates than the methyl-substituted one. The results in aprotic solvents showed quite the opposite, and the reaction rates were considerably lower. In order to explain the obtained results through solvent effects, reaction rate constants (k) of the examined acids were correlated using the total solvatochromic equation of the form: log k=logk0+s?*+a?+b?, where ?* is the measure of the solvent polarity, a represents the scale of the solvent hydrogen bond donor acidities (HBD) and b represents the scale of the solvent hydrogen bond acceptor basicities (HBA). The correlation of the kinetic data were carried out by means of multiple linear regression analysis and the opposite effects of aprotic solvents, as well as the difference in the influence of protic and aprotic solvents on the reaction of the two examined acids with DDM were discussed. The results presented in this paper for cyclohex-1-enylcarboxylic and 2-methylcyclohex-1-enylcarboxylic acids were compared with the kinetic data for benzoic acid obtained in the same chemical reaction, under the same experimental conditions.

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Synthesis and investigation of solvent effects on the ultraviolet absorption spectra of 1, 3-bis-substituted-5, 5-dimethylhydantoins

Journal of the Serbian Chemical Society ◽

10.2298/jsc0310699u ◽

2003 ◽

Vol 68 (10) ◽

pp. 699-706 ◽

Cited By ~ 7

Author(s):

Gordana Uscumlic ◽

Abdulbaseta Kshad ◽

Dusan Mijin

Keyword(s):

Hydrogen Bond ◽

Absorption Spectra ◽

Electronic Absorption Spectra ◽

Alkyl Halide ◽

Substituent Effects ◽

Solvent Polarity ◽

Hydrogen Bond Donor ◽

Hydrogen Bond Acceptor ◽

Isolation Techniques ◽

Energy Relationships

A series of 1,3-bis-substituted-5,5-dimethylhydantoins was synthesized using the reaction of 5,5-dimethylhydantoin with the corresponding alkyl halide in the presence of trimethylamine as catalyst and sodium hydroxide, according to a modified literature procedure. The experimental investigation included modification of the synthetic procedure in terms of starting materials solvent, temperature, isolation techniques, as well as purification and identification of the products. The absorption spectra of the 1,3-bis-substituted-5,5-dimethylhydantoins were recorded in twelve solvents in the range 200?400 nm. The effects of the solvent polarity and hydrogen bonding on the absorption spectra were interpreted by means of linear solvation energy relationships using a general equation of the form ? = ?0 s?* + a? + b? and by two-parameter models presented by the equation ? = ?0 s?* + a?, where ?* is a measure of the solvent polarity/polarisability, ? is the scale of the solvent hydrogen bond donor acidities and ? is the scale of the solvent hydrogen bond acceptor basicities. The solvent and substituent effects on the electronic absorption spectra of the investigated hydantoins is discussed.

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Synthesis and investigation of solvent effects on the ultraviolet absorption spectra of 5-substituted-4-methyl-3-cyano-6-hydroxy-2-pyridones

Journal of the Serbian Chemical Society ◽

10.2298/jsc0108507m ◽

2001 ◽

Vol 66 (8) ◽

pp. 507-516 ◽

Cited By ~ 5

Author(s):

Dusan Mijin ◽

Gordana Uscumlic ◽

Natasa Valentic

Keyword(s):

Hydrogen Bond ◽

Absorption Spectra ◽

Ethyl Acetoacetate ◽

Solvent Polarity ◽

Ultraviolet Absorption ◽

Hydrogen Bond Donor ◽

Reaction Conditions ◽

Hydrogen Bond Acceptor ◽

Energy Relationships ◽

Linear Solvation Energy

A number of 5-substituted-4-methyl-3-cyano-6-hydroxy-2-pyridones from cyanoacetamide and the corresponding alkyl ethyl acetoacetates were synthesized according to modified literature procedures. The alkyl ethyl acetoacetates were obtained by the reaction of C-alkylation of ethyl acetoacetate. An investigation of the reaction conditions for the synthesis of 4-methyl-3-cyano-6-hydroxy-2-pyridone from cyanoacetamide and ethyl acetoacetate in eight different solvents was also performed. The ultraviolet absorption spectra of synthesized pyridones were measured in nine different solvents in the range 200-400 nm. The effects of solvent polarity and hydrogen bonding on the absorption spectra are interpreted by means of linear solvation energy relationships using a general equation of the form v = vo + s?*+a?+b?, where ?* is a measure of the solvent polarity, ? is the scale of the solvent hydrogen bond donor acidities and ? is the scale of the solvent hydrogen bond acceptor basicities.

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6,9-Dibromo-2a,10b-diphenyl-2a,5,10,10b-tetrahydro-2H,3H-2,3,4a,10a-tetraazabenzo[g]cyclopenta[cd]azulene-1,4-dione monohydrate

Acta Crystallographica Section E Structure Reports Online ◽

10.1107/s1600536806011871 ◽

2006 ◽

Vol 62 (5) ◽

pp. o1754-o1755

Author(s):

Neng-Fang She ◽

Sheng-Li Hu ◽

Hui-Zhen Guo ◽

An-Xin Wu

Keyword(s):

Crystal Structure ◽

Hydrogen Bond ◽

Hydrogen Bonds ◽

Water Molecule ◽

Title Compound ◽

Supramolecular Structure ◽

Hydrogen Bond Donor ◽

Hydrogen Bond Acceptor ◽

Compound C ◽

Bifurcated Hydrogen Bond

The title compound, C24H18Br2N4O2·H2O, forms a supramolecular structure via N—H...O, O—H...O and C—H...O hydrogen bonds. In the crystal structure, the water molecule serves as a bifurcated hydrogen-bond acceptor and as a hydrogen-bond donor.

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Machine learning models for hydrogen bond donor and acceptor strengths using large and diverse training data generated by first-principles interaction free energies

Journal of Cheminformatics ◽

10.1186/s13321-019-0381-4 ◽

2019 ◽

Vol 11 (1) ◽

Cited By ~ 3

Author(s):

Christoph A. Bauer ◽

Gisbert Schneider ◽

Andreas H. Göller

Keyword(s):

Machine Learning ◽

Hydrogen Bond ◽

Hydrogen Bonding ◽

Training Data ◽

Free Energies ◽

Hydrogen Bond Donor ◽

Chemical Application ◽

Hydrogen Bond Acceptor ◽

Donor And Acceptor ◽

Target Values

Abstract We present machine learning (ML) models for hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD) strengths. Quantum chemical (QC) free energies in solution for 1:1 hydrogen-bonded complex formation to the reference molecules 4-fluorophenol and acetone serve as our target values. Our acceptor and donor databases are the largest on record with 4426 and 1036 data points, respectively. After scanning over radial atomic descriptors and ML methods, our final trained HBA and HBD ML models achieve RMSEs of 3.8 kJ mol−1 (acceptors), and 2.3 kJ mol−1 (donors) on experimental test sets, respectively. This performance is comparable with previous models that are trained on experimental hydrogen bonding free energies, indicating that molecular QC data can serve as substitute for experiment. The potential ramifications thereof could lead to a full replacement of wetlab chemistry for HBA/HBD strength determination by QC. As a possible chemical application of our ML models, we highlight our predicted HBA and HBD strengths as possible descriptors in two case studies on trends in intramolecular hydrogen bonding.

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A Study on Pathway and QSPR Models for Debromination of PBDEs with Pseudopotential Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.997.25 ◽

2014 ◽

Vol 997 ◽

pp. 25-32 ◽

Cited By ~ 3

Author(s):

Ling Yun Li ◽

Yi Miao Lin ◽

Ji Wei Hu

Keyword(s):

Rate Constants ◽

Polybrominated Diphenyl Ethers ◽

Reaction Rate ◽

Linear Regression Analysis ◽

Basis Set ◽

Pseudopotential Method ◽

Computational Time ◽

Least Squares Regression ◽

Reaction Rate Constants ◽

Qspr Study

Neutral PBDEs congeners and their corresponding radical anions were studied with the pseudopotential method of stuttgart group (SDD) effective-core potentials basis set for the bromine atoms and the all-electron basis set for all other atoms. The pseudopotential method can be used for compounds containing heavy elements with relativistic effects and can reduce the computational time. The quantitative structure property relationship (QSPR) study was also performed in this work to develop models to predict the normolized reaction rate constants for the reductive debromination of polybrominated diphenyl ethers (PBDEs) by zero-valent iron (ZVI). The partial least squares regression (PLSR), principal component analysis-multiple linear regression analysis (PCA-MLR), and back propagation artificial neural network (BP-ANN) approaches were employed for the QSPR study between the molecular descriptors and the logarithm of normalized reaction rate constants of fourteen selected BDE congeners. The results show that the ANN models could be more satisfactorily to predict the rate constants than the PLSR and PCA-MLR models.

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