Group In Para Position Research Articles

Stereochemical Tailoring of Nickel‐based Electrocatalysts for Hydrogen Evolution Reaction

AbstractThe search for alternative non‐noble transition metal catalysts able to evolve hydrogen has been the focus of intense research. Molecular complexes bearing redox‐active ligands have been reported as efficient electrocatalysts for hydrogen evolution reaction (HER). This study showcases a new family of nickel‐thiosemicarbazone complexes displaying significant activity for HER in DMF solvent using trifluoracetic acid as proton source. Following previous works in our group, the ligand was stereochemically tailored, placing methoxy groups at different locations and considering various combinations of positions. Three complexes within the series were shown to outperform the parent catalyst bearing the methoxy group in para position. Overall, the nickel catalyst having the chemical substituent in meta position displays the best catalytic performances while having the lowest overpotential. These results support that ligand stereochemical tailoring in metal complexes improves electrocatalytic HER and suggest that ligand tuning is a promising direction to enhance catalyst performances.

Diastereoselective Dearomatizing Cyclizations of 5-Arylpentan-2-ones by Samarium Diiodide - A Computational Analysis.

This study analyzes the samarium diiodide-promoted cyclizations of 5-arylpentan-2-ones to dearomatized bicyclic products utilizing density functional theory. The reaction involves a single electron transfer to the carbonyl group, which occurs synchronously with the rate determining cyclization event, and a second subsequent proton-coupled electron transfer. These redox reactions are accurately computed employing small core pseudo potentials explicitly involving all f-electrons of samarium. Comparison of the energies of the possible final products rules out thermodynamic control of the observed regio- and diastereoselectivities. Kinetic control via appropriate transition states is correctly predicted, but to obtain reasonable energy levels the influence of the co-solvent hexamethylphosphortriamide has to be estimated by using a correction term. The steric effect of the bulky samarium ligands is decisive for the observed stereoselectivity. Carbonyl groups in para-position of the aryl group change the regioselectivity of the cyclization and lead to spiro compounds. The computations suggest again kinetic control of this deviating outcome. However, the standard mechanism has to be modified and the involvement of a complex activated by two SmI2 moieties is proposed in which two electrons are transferred simultaneously to form the new C-C bond. Computation of model intermediates show the feasibility of this alternative+ mechanism.

Tuning Crystal Packing and Magnetic Properties in a Series of [Dy12] Metallocubanes Based on Azobenzene Derivatives of Salicylic Acid.

A series of four new Dy12 dodecanuclear clusters based on azobenzene derivative ligands of salicylic acid (L1-L4) has been synthesized and characterized in the crystalline phase using X-ray diffraction on single crystal and powder, IR spectroscopy, elemental analysis, and DSC-TGA methods. It was revealed that all obtained clusters exhibit the formation of the similar metallic cluster nodes, as vertex-sharing heterocubanes, obtained from four Dy3+ cations, three bridging hydroxyl groups, and O atoms from the salicylic ligands. The coordination geometry around the Dy(III) centers has been carefully analyzed. Whereas Dy12-L1 and Dy12-L2 with L1 and L2 containing Me and OMe groups in para positions of the phenyl rings, respectively, form similar porous 3D diamond-like molecular networks due to CH-π interactions, for Dy12-L3 with L3 bearing NO2-electron-withdrawing group, the generation of 2D molecular grids assembled by π-π staking is observed, and for Dy12-L4 with L4 bearing phenyl substituent, 3D hexagonal channels have been generated. The complexes Dy12-L1, Dy12-L2, and Dy12-L3 exhibit a zero-field slow magnetic relaxation effect. After UV irradiation of Dy12-L1, a decrease of the magnetic anisotropy energy barrier displaying the possibility of control over magnetic properties by the external stimulus has been observed.

New asymmetric AB3-type free-base and metalloporphyrin-cyclotriphosphazene conjugates: Synthesis and photophysical-photochemical properties

In this work, new asymmetric H2-(3), Zn(II)-(4) and Pd(II)-(5) porphyrin derivatives conjugated with a cyclotriphosphazene ring bearing 2‑naphtoxy groups in paraposition were synthesized and fully characterized. For investigation of photophysical and photochemical properties of these compounds; their ground state absorption, fluorescence emission, fluorescence lifetime, fluorescence quantum yield and singlet oxygen quantum yield measurements were studied in THF. The singlet oxygen quantum yields were determined as 0.62 for 3, 0.49 for 4 and 0.64 for 5 in THF, respectively. As a result, conjugation of the porphyrin macrocycle with the cyclotriphosphazene ring have improved the singlet oxygen generation except compound 4 when compared to tetraphenylporphyrin (TPP) (0.58) and ZnTPP (0.61) in THF. Especially, compound 5 has the highest singlet oxygen quantum yield (0.64) due to the heavy metal effect of Pd(II).

Purely organic Vis-to-UV upconversion with an excited annihilator singlet beyond 4 eV

Biphenyl at its best: a (triisopropylsilyl)ethynyl group in para position converts biphenyl into a UV annihilator that is successfully employed for blue-to-UV upconversion with unprecedented output photon energies.

Evaluation of N-aryl-β-alanine derivatives as anticancer agents in triple-negative breast cancer and glioblastoma in vitro models

Synthesis of β-amino acid derivatives containing hydrazone and azole moieties is described. For this purpose, the appropriate hydrazide was treated with aromatic aldehydes, ketones and phenyl iso(thio)cyanates to obtain the desired outcome. The synthesized target compounds were evaluated for their anticancer properties. The assay displayed 3,3′-((2,6-diethylphenyl)azanediyl)bis(N′-(benzylidene)propanehydrazide) to possess the convincing anticancer effect against triple-negative breast cancer cells in vitro. To further study the anticancer properties of compounds containing a hydrazone moiety in breast cancer, series of previously and newly prepared dihydrazones were investigated. It was determined that derivatives with the bis(N′-(4-bromobenzylidene) fragment in the structure are exclusively cytotoxic to cancer cells. The most active compounds against both cell lines were those containing electron withdrawing 4-BrPh or 4-ClPh moieties, together with either chlorine, bromine or iodine groups in para position of phenyl ring. Selected two representative compounds showed migrastatic activity in MDA-MB-231 cell line, where both of them reduced the growth of breast cancer and glioblastoma cell 3D cultures and inhibited cell colony formation. 2009 Elsevier Ltd. All rights reserved.

Transformation and detoxification of sulfamethoxazole by permanganate (Mn(VII)) in the presence of phenolic humic constituents

In this study, the transformation and detoxification of sulfamethoxazole (SMX, a frequently detected antibiotic in the environments) by permanganate (Mn(VII)) in the presence of model humic constituents (HCs) was evaluated. SMX that hardly react to Mn(VII) was rapidly degraded by Mn(VII) in the presence of catechol (CAT) at pH 5–7, while resorcinol (RES) and hydroquinone (HQ) showed negligible accelerating effect. This enhancing effect was attributed to the 1,4-nucleophilic addition between SMX and o-benzoquinone (o-BQ), an important intermediate generated from oxidation of CAT by Mn(VII). Both Mn(VII) and in-situ formed manganese dioxide (Mn(IV)) accounted for the generation of o-BQ. The experimental results indicated that alkaline condition and excess Mn(VII) were unfavorable for the degradation of SMX by inhibiting the formation of o-BQ. Bioluminescence inhibition assay with vibrio fischeri and data simulated by EPI software showed that the transformation products of SMX retained much less acute toxicity than the parent SMX. Furthermore, the effect of several other HCs structurally related to CAT on the abatement of SMX was explored. The result suggested that the accelerating effect of CAT analogues largely depended on the type of substituent group in para position. Meanwhile, the concentration of manganese in the supernatant was lower than WHO criteria (0.1 mg/L). This work provided a novel and efficiency strategy to detoxify SMX in water treatment.

Molecular structure and electron distribution of 4-nitropyridine N-oxide: Experimental and theoretical study of substituent effects

The molecular structure of 4-nitropyridine N-oxide, 4-NO2-PyO, has been determined by gas-phase electron diffraction monitored by mass spectrometry (GED/MS) and by quantum chemical calculations (DFT and MP2). Comparison of these results with those for non-substituted pyridine N-oxide and 4-methylpyridine N-oxide CH3-PyO, demonstrate strong substitution effects on structural parameters and electron density distribution. The presence of the electron-withdrawing –NO2 group in para-position of 4-NO2-PyO results in an increase of the ipso-angle and a decrease of the semipolar bond length r(N→O) in comparison to the non-substituted PyO. The presence of the electron-donating –CH3 group in 4-CH3-PyO leads to opposite structural changes. Electron density distribution in pyridine-N-oxide and its two substituted compounds are discussed in terms of natural bond orbitals (NBO) and quantum theory atoms in molecule (QTAIM).

OH Group Effect in the Stator of β-Diketones Arylhydrazone Rotary Switches

The properties of several hydrazon-diketone rotary switches with OH groups in the stators (2-(2-(2-hydroxy-4-nitrophenyl)hydrazono)-1-phenylbutane-1,3-dione, 2-(2-(2-hydroxyphenyl)hydrazono)-1-phenylbutane-1,3-dione and 2-(2-(4-hydroxyphenyl)hydrazono)-1-phenylbutane-1,3-dione) were investigated by molecular spectroscopy (UV-Vis and NMR), DFT calculations (M06-2X/TZVP) and X-ray analysis. The results show that, when the OH group is in ortho position, the E’ and Z’ isomers are preferred in DMSO as a result of a stabilizing intermolecular hydrogen bonding with the solvent. The availability, in addition, of a nitro group in para position increases the possibility of deprotonation of the OH group in the absence of water. All studied compounds showed a tendency towards formation of associates. The structure of the aggregates was revealed by theoretical calculation and confirmed by X-ray analysis.

Structural motives controlling the binding affinity of 9,10-bis(methylpyridinium)anthracenes towards DNA

In the search of new DNA groove binding agents a series of substituted 9,10-methylpyridiniumanthracenes have been synthesized and their interactions with DNA have been studied by UV/vis absorption, CD and fluorescence spectroscopy. A minor groove binding mode is confirmed by DNA melting studies, strong CD effects, the dependence of the binding affinity on ionic strength, and the differentiation between AT and GC base pairs. No binding occurs to GC sequences. Binding constants to calf thymus DNA (ct-DNA) and poly(dA:dT) in the range between 1 × 104 and 3 × 105 M−1 have been determined. The binding strength decreases with the size of substituents attached at the anthracene site. Variation of the substitution pattern of the charged groups shows that methyl groups in meta position cause slightly stronger binding than methyl groups in para position. In contrast, with these groups in ortho position, no binding interaction has been observed. The strongest binding is achieved with an expansion of the peripheral heterocycle from pyridine to quinoline. Molecular modeling reveals the pivotal role of the substitution pattern: Anthracenes with para and meta pyridines align along the minor grooves. On the other hand, the ortho derivative adopts no groove-alignment.

Copper(II) complexes of aroylhydrazones: Preparation and structural characterization

Structures of solid copper complexes with aroylhydrazones obtained from nicotinic acid hydrazide and salicylaldehyde derivatives differing in substituents on the benzene ring were analysed by means of infrared (IR) and Raman spectroscopy. Studied aromatic hydrazones acted as neutral, monoanionic or dianionic tridentate ligands, depending on the tautomer form adopted during the complexation process. Various additional substituents on the salicylaldehyde originated ring were not involved in metal coordination, thus carbonyl/enolic oxygen, azomethine nitrogen and oxygen of the phenolic hydroxyl group were proposed as the coordination sites for the copper(II) ion. In all applied synthesis conditions Cu(II) complexes were obtained in Cu(II)/hydrazone molar ratio of 1/1, except for a hydrazone with nitro group, which did not form a complex with Cu(II) regardless of the synthetic conditions. Vibrational spectra indicated that hydrazone having only ortho-hydroxyl group with respect to the double CN bond as well as a hydrazone with an additional OH group in para-position on the benzene ring, formed monomeric copper(II) complexes including water as a ligand, while hydrazones with meta-substituents (Cl, OCH3) formed binuclear copper complexes, in which two copper(II) ions bridge hydrazone molecules via phenolic oxygen atom. Thermal properties of prepared copper(II) complexes were investigated by means of thermogravimetric analysis.

Isomers in chlorido and alkoxido-substituted oxidorhenium(v) complexes: effects on catalytic epoxidation activity.

The syntheses and characterizations of oxidorhenium(v) complexes trans-dichlorido [ReOCl2(PPh3)(L1a)] (trans-2a), cis-dichlorido [ReOCl2(PPh3)(L1b)] (cis-2b) and ethoxido-complex [ReO(OEt)(L1b)2] (4b), ligated with the dimethyloxazoline-phenol ligands HL1a and HL1b are described. The bidentate ligand HL1a (2-(4,4-dimethyl-4,5-dihydro-1,3-oxazol-2-yl)-phenol) is unsubstituted on the phenol ring; ligand HL1b (2-(4,4-dimethyl-4,5-dihydro-1,3-oxazol-2-yl)-4-nitrophenol) contains a nitro group in para-position to the hydroxy group. In the reaction of precursor complex [ReOCl3(PPh3)2] and HL1a the two stereoisomers cis/trans-2a, with respect to chlorido ligands, are formed. The solid state structures of both isomers cis- and trans-2a were determined by single crystal X-ray diffraction analysis. In contrast, with ligand HL1b, only the cis-isomer cis-2b was obtained. Ethoxido-complex 4b is exclusively obtained when precursor [ReOCl3(OPPh3)(SMe2)] is reacted with 2 equiv. of HL1b in ethanol in the presence of the base 2,6-dimethylpyridine (lutidine). If no lutidine is added, chlorido-complex [ReOCl(L1b)2] (3b) is obtained. Complexes [ReOCl2(PPh3)(L1a)] (cis/trans-2a), [ReOCl2(PPh3)(L1b)] (cis-2b), [ReO(OMe)(L1a)2] (4a) and [ReO(OEt)(L1b)2] (4b) were tested as homogeneous catalysts in the benchmark reaction of cyclooctene epoxidation. The influence of isomerism and effects of ligand substitutions on catalytic activity was investigated. Based on the time-conversion plots it can be concluded that cis/trans-isomerism does not influence catalytic activity, but electron-withdrawing substituents, as in cis-2b, 3b and 4b, show a beneficial effect.

Synthesis and biological evaluation of coumarin derived chalcones as potent antimicrobial and antioxidant agents

Coumarin derivatives are important biologically active compounds with anti-cancer, antimicrobial, anti-inflammatory, anti-HIV, anti-oxidant, anti-coagulant, anti-tubercular, anti-psychotic, and anti-malarial activities. Chalcones are the most common and simple class of aromatic five-membered heterocycles with anti-cancer, anti-oxidative, antibiotic, anthelmintic, anti-inflammatory, anti-hypertensive, and anti-HIV activities. Based on the above literature, an attempt was made to synthesize some new styryl coumarin derived chalcones and evaluated for antimicrobial and antioxidant activities. Acetyl 7-methyl coumarins were synthesized from 4-methyl salicylaldehyde, which on treating with various aromatic aldehydes in the presence of alkalinemethanol yielded various coumarin chalcone derivatives. These molecules on treating with various aromatic aldehydes yielded the title compounds (SCC 1-10). The synthesized title compounds were evaluated for antimicrobial and antioxidant activities. All the synthesized compounds were characterized by IR, NMR, and mass spectroscopy and screened for antimicrobial and antioxidant activities. Among the compounds SCC 1-10, compound SCC 7, 9, and 10 showed potent activity, and compounds 3, 4 and 8, showed moderately potent antibacterial activity. Compounds SCC 3, 7, 9 showed potent and compounds 5, 6, and 8 showed moderately potent antifungal activity. Compounds SCC 3, 4, 7, and 9 showed potent antioxidant activity. From the results, it was concluded that the compounds bearing nitro and chloro group have shown prominent activity when compared to compounds without these groups. It was also confirmed that the groups in para position showed better activity when compared to the groups in ortho position. The above results establish the fact that styrylcoumarin fused with chalcone can be a rich source for exploitation.

Применение 1,3-диоксолана в синтезе замещенных 3,4-дигидрохиназолинов, диарилметанов или метилендиаминов

The interaction between 1,3-dioxolane with primary aromatic amine- sulfanilamide (streptocide), secondary aromatic amine-N-benzylaniline and also with amine of heterocyclic series – 4-aminopyridine. It is found that, sulfanilamide (streptocide), which has an electron withdrawing sulfonamide group in para position, reacts with 1,3-dioxolane in an atmosphere of benzol and trifluoroacetic acid producing 3-(4-sulfamoylphenyl)-3,4-dihydroquinazoline-6-sulphonamide, that is corresponding to the previous result obtained when 1,3-dioxolane reacts with para-nitroaniline (which also contains electron-withdrawing nitrogroup) resulting in 3-(p-nitrophenyl)-6-nitro-3,4-dihydroquinazoline. Under the same conditions the interaction between 1,3-dioxolane and N-benzylaniline results in producing 4,4'-bis(phenylmethyleneamino)diphenylmethane, which refers to a different class of compounds – diphenylmethane derivative. A primary amine of heterocyclic series 4-aminopyridine reacts with 1,3-dioxolane in the presence of concentrated hydrochloric acid producing N,Nʹ-di-(4-pyridinyl)methylenediamine. Antimicrobic properties of received compounds were studied on museum potentially pathogenic microorganism strains: Staphylococcusaureus (strain 906), Candid aalbicans (АТСС 24433), in FSBI «Scientific Centre for Expert Evaluation of Medicinal Products» of the Ministry of Health of the Russian Federation. Only N,Nʹ-di-(4-pyridyl)methylenediamine out of three investigated compounds showed microbiological activity. This compound inhibits growth of Staphylococcus aureus at concentration 62.5 µg/ml, culture death comes from the effect of concentration 125.0 µg/ml. The morphology of compounds was established according to mass spectrometry data, 1Н NMR spectroscopy, the structure of N,Nʹ-di-(4-pyridyl)methylenediamine in the form of chloride was proved using X-ray structural analysis.

Physicochemical Properties Govern the Activity of Potent Antiviral Flavones

Ladanein (i.e., 5,6,7-trihydroxylated flavone) was demonstrated to act as a powerful virucidal agent toward a broad range of enveloped virus particles. Fe(III) coordination and pH are indeed among the key parameters that might favor both bioactivation of the flavone and consequent host cell entry inhibition. In this present work, the impact of fluorinated groups on the physicochemical and antiviral properties of the flavone was investigated, thus allowing a deeper understanding of the antiviral mode of action. The improved synthesis of ladanein allowed accessing a broad range of analogues, some of them being significantly more active than the former ladanein lead compound. We first determined the acido-basic properties of this homogenous series of compounds and then investigated their electrochemical behavior. Fe(III) coordination properties (stability, spectral behavior, and kinetics) of ladanein and its analogues were then examined (quasiphysiological conditions) and provided key information of their stability and reactivity. Using the determined physicochemical parameters, the critical impact of the iron complexation and medium acidity was confirmed on hepatitis C virus (HCV) particles (pre)treated with ladanein. Finally, a preliminary structure–HCV entry inhibition relationship study evidenced the superior antiviral activity of the ladanein analogues bearing an electron-withdrawing group in para position (FCF3 > FOCF3 > FFCF3 > FF > FOMe) on the B cycle in comparison with the parent ladanein itself.

Increasing and eliminating the (Fecal coliforms, thermotolerant coliform and fecal streptococcus) bacteria by resin of the poly (para carboxy acid phenol-d-Glucose) to clean up waste water

In this research paper we represent a novel synthetic antibacterial phenolic polymer (pAP-DG) containing carboxylic acid group in para position. The study of poly (p-carboxylic acid phenol d-Glucose) as an antibacterial resin was focused on the development of antimicrobial polymers to clean up the water of pathogenic bacteria. The polycondensation reaction was realized between p-carboxy acid phenol (pAP) and d-Glucose (DG) as monomers; using sulfuric acid as homogeneous catalyst.The obtained polymer was used via fecal coliform (TC), thermotolerant coliforms (CTT) and fecal streptococci (ST) bacteria to evaluate the water quality. The antibacterial activity of the synthesized resin was carried out by the contact method so the capacity of this resin was confirmed. In general, the polymer has a good antimicrobial activity against the microorganisms tested; the resulting polymer was characterized by various spectroscopy methods such as: 1H NMR, 13C NMR, DSC and FTIR and a mechanism has been proposed for this polycondensation reaction.

Internal path investigation of the acting electrons during the photocatalysis of panchromatic ruthenium dyes in dye-sensitized solar cells

A series of heteroleptic Ru(II) complexes were theoretically investigated using time-dependent density functional theory. These dyes, including K8 and N3, are based on a common motif formed by Ru center, N C S, and polypyridyl ligands, but differ only by the nature of the added group in para position of each pyridyl. The presence of these ligands will enable the evaluation of the electronic effects ±I and ±M. This work focuses on the localization of the part, among the metal, the N C S, the polypyridyl ligands, and the added group R, which is most actively involved in the photocatalysis process. We dealt with both ground and excited states as well as the electronic transitions between them. To illustrate the effect of each functional group R on its photophysical properties, the geometries of five dyes were optimized in the molecular and univalent cationic states. All molecules are asymmetrical in shape with a distorted octahedral coordination of the RuN6 core. Atomic charge and spin density distributions show that a charge transfer process occurs from the NCS/Ru to polypyridyl ligand. Analysis of the electronic absorption spectra reveals that the band with the highest wavelength value is assigned to metal-to-ligand charge transfer transition. On the contrary, two other bands are assigned to multitransitions Ru/NCS to polypyridyl–π*. These attributions have been confirmed by the localization of all atoms intervening in them. We also introduced an adapted way to estimate the ionization probability values in each atomic center in the ground and first excited states. Phenomenal properties such as mobility, redox potential, electronic spectrum, ionization potential, and optical gap of the most efficient dye, which is the N3, fit well with experimental values.

Polyelectrolytes based on poly(p-acryloyloxybenzaldehyde) with arsonic acid groups useful in the colloidal synthesis of silver nanoparticles

Several methods have been developed for synthesis of Ag nanoparticles. However, Ag nanoparticles are unstable materials, and they tend to agglomerate losing their properties. Polymers are commonly employed for the stabilization of Ag nanoparticles in colloidal solutions. Polymers with ionic groups such polyelectrolytes can stabilize metallic nanoparticles through electrostatic and steric effects. In this work we employed poly(p-acryloyloxybenzaldehyde) and their derivates containing arsonic acid groups in ortho and para positions as reducing and stabilizing agents in the synthesis of Ag nanoparticles. Polyelectrolytes containing arsonic acid groups in ortho position were better reducing agents than the poly(p-acryloyloxybenzaldehyde) and the polyelectrolyte with arsonic acid group in para position, leading to the reduction of Ag+ ions in short reaction time. The polyelectrolyte with arsonic acid groups in para position was the best stabilizing agent leading to obtaining Ag nanoparticles with the smallest average size.

Ab initio study of polar and non-polar aprotic solvents effects on some 3-hydroxychromones and 3-hydroxyquinolones derivatives.

The photophysical properties of some 3-hydroxychromones (3-HC) and 3-hydroxyquinolones (3-HQ) derivatives are investigated in polar and non-polar aprotic solvents using the TDDFT method and the PCM formalism. In acetonitrile and n-hexane, 2-(2-benzothienyl)-3-HC) (BTHC), 2-furyl-3-HQ (FHQ), and 1-methyl-2-furyl-3-HQ (MFHQ) have exhibited dual emission bands due to the excited state intramolecular proton transfer (ESIPT) reaction, leading to a single excited tautomer form. Our results indicate a very high BTHC light absorption efficiency and radiative rate constant. A charge transfer (CT) analysis suggests that the chromone moiety acts as an acceptor group while quinolone moiety acts as an electron donor. In addition, in non-polar n-hexane the furyl group may act as an acceptor, while in polar acetonitrile it may act as an electron donor. The energies of the upper and lower states of the normal form fluorescence have been decreased by the introduction of ortho-methyl group in FHQ. In all states, MFHQ exhibits large distortions of the dihedral angle between the chromone moiety and the furan group in para position. The ESIPT reaction is irreversible for the three derivatives in all cases studied in this work. Since experimental data with n-hexane are not available, results concerning this solvent are only predictions.

Development of Predictive QSAR Models of 4-Thiazolidinones Antitrypanosomal Activity Using Modern Machine Learning Algorithms.

This paper presents novel QSAR models for the prediction of antitrypanosomal activity among thiazolidines and related heterocycles. The performance of four machine learning algorithms: Random Forest regression, Stochastic gradient boosting, Multivariate adaptive regression splines and Gaussian processes regression have been studied in order to reach better levels of predictivity. The results for Random Forest and Gaussian processes regression are comparable and outperform other studied methods. The preliminary descriptor selection with Boruta method improved the outcome of machine learning methods. The two novel QSAR-models developed with Random Forest and Gaussian processes regression algorithms have good predictive ability, which was proved by the external evaluation of the test set with corresponding Q2ext =0.812 and Q2ext =0.830. The obtained models can be used further for in silico screening of virtual libraries in the same chemical domain in order to find new antitrypanosomal agents. Thorough analysis of descriptors influence in the QSAR models and interpretation of their chemical meaning allows to highlight a number of structure-activity relationships. The presence of phenyl rings with electron-withdrawing atoms or groups in para-position, increased number of aromatic rings, high branching but short chains, high HOMO energy, and the introduction of 1-substituted 2-indolyl fragment into the molecular structure have been recognized as trypanocidal activity prerequisites.