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1,3-Cyclohexadienes are an important group of molecules found in natural compounds and their metabolites. In this contribution, optimization, spectral prediction, reactivity, and molecular docking studies of 3-aminocyclohexa-2,6-diene-1-sulfonic acid were performed. The structure was optimized based on the crystallographic structures of cis-(1S)-3-Fluoro-3,5-cyclohexadiene-1,2-diol and 1,1′-(3,5-Cyclohexadiene-1,3-diyl)dibenzene. The most intense transitions in the predicted spectrum were observed at 195, 222, 235, and 324 nm. The molecular orbitals included in these transitions were partially localized on polar groups. The explicit solvent effect was investigated through optimization of structure with one water molecule. The strength of these interactions was assessed by the Natural Bond Orbital Theory and Quantum Theory of Atoms in Molecules. Three different dimer structures were also optimized to obtain the interaction energy for various active positions. The most stable dimer was formed through the interaction of amino and sulfonic groups. The reactivity parameters for three cyclohexadiene were calculated and discussed from the structural point of view. The docking study towards Urokinase Type Plasminogen Activator (uPa) proved the importance of various substituents. Once the dimers were used as ligands, the binding energy increased. These results show the possible use of cyclohexadienes as uPa inhibitors. The optimization of 3-aminocyclohexa-2,6-diene-1-sulfonic acid (1), cis-(1S)-3-Fluoro-3,5-cyclohexadiene-1,2-diol (2) and 1,1′-(3,5-Cyclohexadiene-1,3-diyl)dibenzene (3) compounds was performed at the B3LYP/6-311++G(2df,2p) level of theory. Strong hydrogen bonds were formed with amino and sulfonic groups. The dimer structures proved the importance of intermolecular interactions between polar groups. The docking results towards Urokinase Type Plasminogen Activator (uPa) proved the reactivity order determined previously along with the interactions with the amino acids in an active pocket. [ABSTRACT FROM AUTHOR]

The phenolic compounds, which are rich in red wine, have gained considerable attention due to their antioxidant potential. Selected Serbian wines were analyzed for their antioxidant activity by DPPH test and the total content of phenolic compounds was determined by employing the Folin–Ciocalteu colorimetric method. The major polyphenols were determined by HPLC. The antioxidant activity was correlated with the amount of specific polyphenols (gallic acid, caffeic acid, catechin, epicatechin, myricetin, and kaempferol) by quantitative structure–activity relationship. The origin of the antioxidant potential of wines was discussed based on the individual activity of identified polyphenols and theoretical calculations (at APFD/6-311++G(d,p) level of theory). The thermodynamic parameters of free radical scavenging activity and reactivity towards DPPH·, HO·, and HOO· were explained with special emphasis on the effect of structure and intramolecular interactions in polyphenols. Based on the presented data, the positive effects of selected Serbian wines on humane health and biologically relevant free radicals are concluded. [ABSTRACT FROM AUTHOR]

The electrochemistry of catecholamine neurotransmitters and their precursor l-dopa has been widely studied due to their relevance as biologically important compounds. The detection of these compounds from aqueous solution is hindered by the coexistence of quinone or hydroquinone. However, it was suggested that quinones adsorbed on the electrode surface can enhance catechol detection. In order to estimate the degree of interaction between quinones and l-dopa, cyclic voltammetry and UV–Vis spectroscopic study was performed. A sesquiterpenoid hydroquinone, isolated from the marine sponge Dysidea avara (avarol), has been used in this study. The change of apparent heterogeneous rate constant with different avarol/l-dopa ratio indicated that charge transfer could be enhanced at some extent. In addition to this, the obtained results for avarol and hydroquinone (its structural element) were compared. UV–Vis spectroscopic analysis confirmed interaction between l-dopa and avarol or hydroquinone. Taken all together, the interaction of l-dopa was stronger with hydroquinone than with avarol, presumably reflecting the conformational restrains of avarol caused by its terpenoid moiety. [ABSTRACT FROM AUTHOR]

The equilibrium geometries and chemical reactivities of the novel coumarine derivative, 3-[1-(3-hydroxypropylamino)ethylidene]chroman-2,4-dione, in water and benzene were investigated. The Fukui parameters, calculated by the Natural and Atoms in Molecules charges, were determined for all atoms in both phases. The most potent sites for the electrophilic, nucleophilic, and radical attack are discussed. Molecular docking analysis was carried out to identify the potency of inhibition of the title molecule against human cartilage proteins. The inhibition activity was obtained for ten conformations of ligand inside protein. This study proved that the Fukui indices can be used as the reactivity descriptors for the novel substances with inhibitory activity. Graphical abstract: [ABSTRACT FROM AUTHOR]