Parameters In Structure-activity Relationships Research Articles

The power of novel morpholinyl Mannich bases to protect N80 steel against corrosion in acidic environment: DFT and SAR investigations

In this research article, we investigate the corrosion inhibition properties of two novel morpholinyl mannich bases namely 3-morpholino-1-phenylpropan-1-one (MB1) and 3-morpholino-1-phenyl-3-(pyridin-4-yl) propan-1-one (MB2). To establish a link between their corrosion inhibition efficacy and molecular characteristics, we employ a comprehensive approach involving the calculation of DFT-derived global and local reactivity parameters, as well as structure-activity relationship (SAR) indices. The obtained values of the global reactivity indices including dipole moment, energy gap, hardness, and softness show a positive correlation with the experimental data earlier reported. Fukui functions give a comprehensive reactive scheme exhibiting the atoms responsible for the electronic transfer. SAR parameters such as molecular volume (V), surface area (SA), and the polarizability (α) were found to be in good accordance with the experimental inhibition effectiveness order.

Aqueous OH kinetics of saturated C6–C10 dicarboxylic acids under acidic and basic conditions between 283 and 318 K; new structure-activity relationship parameters

Bimolecular reaction rate coefficients (kOH) for reaction of hydroxyl radicals (OH) with adipic, pimelic, suberic, azelaic, sebacic and cis-pinonic acids were measured in aqueous phase for the neutral (pH = 2) and completely deprotonated (pH = 9) forms of the acids listed. Reactions were carried out in bulk solution between 283 and 318 K. Camphoric acid was used as a reference compound for measuring kOH values using a relative rate method, and with hydrogen peroxide (H2O2) as a photochemical source of OH. Concentrations of the reactants were monitored with liquid chromatography coupled with electrospray tandem mass spectrometry (LC-ESI/MS2).The kOH values measured were between 1 and 8 × 10−9 M−1s−1; only adipic and pimelic acids showed a significant pH-dependence to their OH reactivity. The kinetic data acquired and the data reported in the literature for camphoric, glutaric and succinic acids were used to optimize new structure-activity relationship (SAR) parameters. The SAR developed here allowed accurate prediction of kOH values for aliphatic carboxylic acids in the temperature range between 283 and 318 K. The accuracy of the developed SAR was evaluated against the experimental kOH values measured in this work and obtained from the literature data. Moreover, this work is the first to accurately predict the temperature-dependent kOH values for carboxylic acids.

A theoretical study on electronic structure and structure–activity properties of novel drug precursor 6‐acylbenzothiazolon derivatives

AbstractIn this work, electronic properties and structure–activity relationship (SAR) parameters of 20 novel drug precursor 6‐acylbenzothiazolon derivatives with analgesic activity have been investigated theoretically by performing Austin Model‐1 (AM1) and DFT‐B3LYP/6‐31G (d) calculations with the aim to correlate the properties of each substance—particularly electronic properties and SAR parameters—with the biological interactions that are linked to their pharmacological effects. Their molecular properties were related to the biological activity of these drug precursor molecules. The relationship between octanol–water partition coefficient (log P) and each of the SAR parameters [ELUMO–HOMO, molecular volume (Vm), ionization potential (IP), electron affinity, electronegativity (χ), chemical hardness (η), chemical softness (S), electrophilic index (ω), and molar refractivity] present linear correlation except for IP and χ. This result suggests that there are future prospects for designing or developing new drugs based on the correlation between the theoretically calculated parameters. According to AM1 calculation, the values of heat of formation of 6‐acylbenzothiazolon derivatives are negative (exothermic), which shows that these molecules are thermodynamically stable. ELUMO–HOMO energy levels of the studied molecules are 4–5 eV, which also indicate that they are kinetically unstable. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011

Use of calculated quantum chemical properties as surrogates for solvatochromic parameters in structure-activity relationships

Use of calculated quantum chemical properties as surrogates for solvatochromic parameters in structure-activity relationships