In vitro immunohistochemical investigations on the human hepatoma cell line (Huh7) infected with hepatitis C virus (HCV) strain JFH-1 showed that AV0012 compound blocks the early stages of viral infection. AV0012 also blocked viral infection spread in tissue culture through the secreted virus and through tight cell-to-cell contact. AV0012 is a specific inhibitor of HCV but not of related pestivirus, flaviviruses and other RNA-containing viruses such as bovine diarrhea (BVDV), Venezuelan equine encephalitis (strain TC-83), dengue type 2 (New Guinea), yellow fever (strain 17D), west Nile fever, parainfluenza (type 3) virus, RSV (strain A2), and Rhinovirus (type 2 strain HGP). It is established that human serum does not significantly affect the antiviral activity of AV0012 in vitro. The drug combination studies with AV0012 and interferon alpha 2a in vitro showed that the two inhibitors act additively, which makes possible the use of this combination in clinical tests. AV0012 is highly soluble and stable in aqueous solutions and murine blood plasma, has limited metabolic stability, low binding to human plasma proteins, high permeability through biological membranes, and only interacts with isoenzymes 2D6 and 3A4 of human cytochrome P450. In animal pharmacokinetic studies, AV0012 was rapidly absorbed into the blood stream upon oral administration, showed sufficiently long half-elimination times, and had high oral bioavailability that reached 92% in monkeys. Further preclinical development of AV0012 is in progress.

Several novel compounds were found to be potent inhibitors of the HCV (JFH-1 isolate) infection in vitro. Human serum did not significantly reduce antiviral activity of the lead compound, AVR560 (< 4-fold). The immunohistochemistry studies with the Huh7 cell line, infectable with the HCV (JFH-1 strain), demonstrated that AVR560 inhibited the early steps of viral infection and blocked the spread of the HCV infection in tissue culture. The cytotoxicity in Huh7 and Vero-76 cell lines was mild. AVR560 proved to be a specific HCV inhibitor and exhibited no activity against other flaviviruses such as yellow fever (strain 17D), West Nile (strain NY99), and dengue (New Guinea type 2) in in vitro infection experiments. AVR560 also did not inhibit any of the tested human CYP450 isozymes (3A4, 1A2, 2C19 and 2D6). In the pharmacokinetic studies in mice, rats and dogs, favorable pharmacokinetic profiles and good oral bioavailability were observed for AV560. Further pre-clinical studies with this novel HCV inhibitor are in progress.

New substituted ethyl 5-hydroxy-1,2-dimethyl-1 H -indole-3-carboxylates and 7,8-dimethyl-1,2,3,7-tetrahydro[1,3]oxazino[5,6- e ]indole-9-carboxylates including arbidol analogs in addition to 6-hydroxy-1-methyl-7-pyridin-3-yl-4,5-dihydropyrrolo[4,3,2- de ]isoquinolin-3(1 H )-ones and 1,4-dimethyl-7-pyridin-3-yl-2-(phenylsulfonylmethyl)-1,4-dihydropyrrolo[4,3,2- de ]isoquinoline-3,6-dione were synthesized. Their antiviral activity against influenza A/New Caledonia/20/99 virus (H 1 N 1 ), bovine viral diarrhea virus (BVDV), and hepatitis C virus (HCV) was studied. It was found that the synthesized compounds were not noticeably active against these viruses. The exceptions were only ethyl 5-hydroxy-4-(dimethylaminomethyl)-1-methyl-6-pyridin-3-yl-2-(phenylsulfinylmethyl)-1 H -indole-3-carboxylate and 5-hydroxy-1,2-dimethyl-6-fluoro-1 H -indole-3-carboxylate hydrochlorides, which exhibited micromolar activities EC 50 = 6.6 and 9.8 ìM, respectively, against a human hepatoma cell line (Huh7.3) with increased sensitivity to HCV infection (strain JFH-1, genotype 2a).

Показано, что человеческая сыворотка практически не влияет на противовирусную активность AVR560 in vitro по отношению к HCV. Проведено иммуногистохимическое исследование AVR560 на модели клеточной линии гепатомы человека (Huh7), зараженной HCV (штамм JFH-1), и показано, что он блокирует раннюю стадию вирусной инфекции, а также подавляет ее распространение. Установлено, что AVR560 является специфическим ингибитором HCV и не активен по отношению к другим флавивирусам, таким как вирусы Западного Нила (штамм NY99), желтой лихорадки (штамм 17D) и Денге, тип 2 (New Guinea). Показано, что AVR560 не проявляет ингибирующей активности по отношению к изоферментам CYP3A4, CYP1A2, CYP2C19 и CYP2D6с цитохрома P450 человека. Изучена фармакокинетика AVR560 на грызунах и собаках при пероральном и внутривенном введении, определены основные фармакокинетические параметры и биодоступность.

New substituted ethyl 1,2-dimethyl-5-hydroxy-1 H -indole-3-carboxylates and 7,8-dimethyl-1,2,3,7-tetrahydro[1,3]oxazino[5,6-e]indole-9-carboxylates, including arbidol analogs, and also 6-hydroxy-1-dimethyl-7-(pyridin-3-yl)-4,5-dihydropyrrolo[4,3,2-de]isoquinolin-3(1 H )-ones and 1,4-dimethyl-2-(phenylsulfonylmethyl)-7-(pyridin-3-yl)-pyrrolo[4,3,2-de]isoquinoline-3,6(1H,4H)-dione, have been synthesized. The antiviral activity of these compounds against influenza A/New Caledonia/20/99 (H 1 N 1 ), bovine viral diarrhea (BVDV) and hepatitis C (HCV) viruses has been studied in vitro . Among all the drugs studied, only two compounds (ethyl 5-hyroxy-4-(dimethylaminomethyl)-1-methyl-6-piridine-3-yl-2-(phenylsulfonylmethyl)-1 H -indole-3-carboxylate and 5-hyroxy-1,2-dimethyl-6-fluoro-1 H -indole-3-carboxylate) significantly inhibited HCV in the in vitro-infected cultured human hepatoma (Huh 7.3) cells (with EC 50 of 6.6 and 9.8 mM, respectively).

A series of new 3-(arylsulfonyl)-2-(methylthio)pyrazolo[1,5- a ]pyrimidines containing amino substituent in position 7 have been synthesized and their 5-HT6 receptor antagonist activity has been studied. It is established that the transition from 7-amino and 7-dimethylamino derivatives to 7-aminoalkyl derivatives is accompanied by a significant decrease in the activity, and a similar effect is observed upon replacement of methyl group in position 5 with phenyl or 5-thiophen-2-yl substituents. Maximum (picomolar) activity in the obtained series of compounds was displayed by 5-methyl-2-(methylthio)-3-(phenylsulfonyl)pyrazolo[1,5- a ]pyrimidine-7-amine and N,N,5,6-tetramethyl-2-(methylthio)-3-(phenylsulfonyl)pyrazolo[1,5- a ]pyrimidine-7-amine ( K i = 700 pM). The first representative of hydrogenated pyrazolo[1,5- a ]pteridines – 5,6,9-trimethyl-2-(methylthio)-3-(phenylsulfonyl)-6,7,8,9-tetrahydropyrazolo[1,5- a ]pteridin (with K i = 14,4 nM) was synthesized. The discovered structure – 5-HT 6 antagonist activity relationship and observed regularities confirm the validity of the adopted pharmacophore model, which allows it to be used in the search for effective drug candidates.

High-throughput screening of a specific set (focused library) of heterocyclic compounds containing alkylsulfonyl moiety (a total of 2827 compounds from 78 combinatorial libraries), has been performed and highly effective 5-HT6 receptors antagonists were discovered. The structure of most substances corresponds to the PhM2 pharmacophore model, which confirms its potential in the search for effective 5-HT6 receptor antagonists. It is established that the structure of a substituent introduced in the vicinity of the sulfonyl moiety in PhM2 ligands can affect their pharmacological activity, including the ability to block serotonin-induced 5-HT6 receptor-mediated cell responses. In particular, bulky electron-donor groups reduce the activity, whereas methylamine group significantly increases the 5-HT6 receptor antagonist ability of compounds. Based on these findings, a new conceptual pharmacophore model, PhM3, is proposed. It is shown that compounds from the combinatorial libraries with (i) sulfonyl moiety separated from the heterocyclic and/or aromatic moiety by one (or more) methylene carbon(s), (ii) heterocyclic compounds containing alkylsulfonyl moiety or endocyclic sulfonyl group, (iii) (5-arylsulfonyl-3H-[1,2,3]triazol-4-yl)-amines, and (iv) azoles substituted simultaneously with arylsulfonyl and alkylsulfonyl groups-all have low hit rate and, hence, are not promising for discovery of new 5-HT6 receptor antagonists.

In continuation of studies on 3-(phenylsulfonyl)pyrazolo[1,5-a]pyrimidine derivatives as 5-HT6 receptor antagonists, new compounds with a pyridine moiety in the 5-and/or 7-position were obtained and their antagonistic activity was screened. It was established that the introduced pyridine changed the 5-HT6 activity. Some of the obtained 5-pyridin-3-yl-3-(phenylsulfonyl)pyrazolo[1,5-a]pyrimidines 5-HT6 receptor antagonists with K i = 0.2 – 4.5 nM had therapeutic significance for the treatment of some CNS diseases.

Синтезированы 3-(арилсульфонил)-2-(метилтио)пиразоло[1,5-a]пиримидины, содержащие в положении 6 заместители, включающие аминогруппу, изучена связь их структуры с антагонистической активностью по отношению к серотониновым 5-НТ6 рецепторам. Показано, что наиболее активными пикомолярными лигандами являются 2-(метилтио)- 3-(фенилсульфонил)- и 2-(метилтио)-3-(3-хлорфенилсульфонил)пиразоло[1,5-a]пиримидин-6-амины, активность которых сопоставима с описанными ранее 3-(арилсульфонил)-2-(метиламино)пиразоло[1,5-a]пиримидин-6-аминами, 3-(арилсульфонил)-2-(метил- амино)- и 3-(арилсульфонил)-2-(метилтио)пиразоло[1,5-a]пиримидин-7-аминами.

Aiming the search for new effective 5-HT 6 receptor antagonists, both new and known (4-phenylsulfonyloxazole-5-yl)amine derivatives containing differently substituted sulfonyl group have been studied. Based on the structure – 5-HT 6 antagonist activity relationship, a new pharmacophore model for 5-HT 6 antagonists is proposed. A strong influence of vicinal electron-donor substituent (methylthio or methylamino group) on the ligand – receptor interaction has been observed and explained by additional hydrogen bonding. 3D structure optimization of arylsulfonyloxazoles by molecular mechanics method, as well as conformation calculations show that topological features of the ligand molecules are particularly responsible for their 5-HT 6 antagonist activity. Replacement of the methyl radical by a more bulky alkyl radical, as well as the passage to tertiary amines, is accompanied by a dramatic decrease in this activity.

In continuation of studying derivatives of 3-(phenylsulfonyl)pyrazolo[1,5-a ]pyrimidines as 5-HT6 antagonists, new compounds with pyridine moiety in positions 5 and/or 7 were obtained and their antagonistic activity was evaluated. It is established that the introduced pyridine changes 5-HT6 activity. Some of the obtained 3-(phenylsulfonyl)pyrazolo[1,5-a] pyrimidines with Ki = 0.2 - 4.5 nM have therapeutic significance for the treatment of some CNS diseases.

Разработаны методы синтеза дибром-производных индометацина и N-алкилированных ауксинов на их основе. Изучены некоторые способы введения в структуру этих 3-индолилуксусных кислот различных заместителей на примере азотсодержащих функциональных групп. Исследована противовирусная активность некоторых соединений в отношении вируса гриппа А/Аичи/2/69 в культуре клеток MDCK и на модели гриппозной пневмонии у мышей.

Several analogs of the antihistamine drug dimebon have been synthesized with different linkers connecting a picoline fragment to the tetrahydropyridoindole core. Radioligand activity profiles of the obtained compounds have been studied using a broad set of 30 therapeutic targets. Reduction of the linker length is shown to cause substantial shifts in the activity profiles.

Methods for the synthesis of dibromo-substituted derivatives of indomethacin and related N -alkylated indole-3-acetic acid derivatives have been developed. Pathways for the introduction of various substituents, in particular nitrogen-containing groups, into the structure of auxins have been studied. The antiviral activity of some brominated functionally substituted compounds with respect to A/Aichi/2/69 influenza virus in MDCK cell culture and an influenza pneumonia model in mice has been evaluated.

The toxicity of new gamma-carboline derivative [ethyl 3-(8-fluoro-2-methyl-2,3,4,5-tetrahydro-1H-gamma-carbolin-5-yl)-propionate dihydrochloride, CD-008-040] has been studied.

The properties of 2,3,4,5-tetrahydro-1H-gamma-carbolines containing acid, ether, and amido-substituents, were assessed as potential antagonists of histamine H1 receptors (H1R), capable of blocking histamine-induced calcium fluxes in SK-N-SH cells. The structure--activity relationship for their antagonistic activity is discussed. Among the gamma-carbolines used in the study, the antihistamine activity considerably depends on the nature of substituents in positions 2, 5, and 8 of the heterocycle. The most active antagonist, ethyl 3-(2-methyl-8-fluoro-2,3,4,5-tetrahydro-1H-gamma-carboline-5-yl)propionate, with high affinity to the H1R (Ki = 6.5 nM), produces no adverse effects on motor activity of mice in doses 1-40 mg/kg, which shows the absence of a sedative effect.

The influence of ethyl-3-(8-fluoro-2-methyl-2,3,4,5-tetrahydro-1H-gamma-carboline-5-yl)propionate dihydrochloride belonging to the class of gamma-carbolines on the allergic reactions (inflammation and systemic anaphylaxis) has been studied on laboratory animals. It was established that the given substance administered in a dose of 5 - 20 mg/kg exhibits a pronounced antiallergic action. Unlike many other antihistamine drugs, this gamma-carboline derivative probably does not produce sedative effect.

The synthesis, molecular docking, and biological testing of a series of new heteroaryl-substituted oxadiazole-5-carboxamide inhibitors of glycogen synthase kinase 3β (GSK-3β) are described. The synthesis includes several stages and is based on the advanced liquid-phase combinatorial approach. Molecular docking was used for the rational selection of synthesized compounds for the subsequent biological testing. It is established that the inhibitory activity of the synthesized compounds strongly depends on the character of substituents in the phenyl ring and the nature of terminal heterocyclic fragments. The most active compounds inhibit GSK-3β at IC 50 in the micromolar range and can be considered as potential drug candidates.

A parallel solid-phase synthesis of combinatorial library of 436 amides of 4-(3,7-diorganyl-3,7-diazabicyclo[3.3.1]nonan-2-yl)butanoic acid has been accomplished starting from natural alcaloid (−)-cytisine. A five-step liquid-phase synthesis resulted in the conversion of cytisine to 7-benzyl-3-[(9 H -fluoren-9-yl)methyl]-substituted acids, which were further diversified with the use of solid-phase technology on the acid-susceptible amine resins. The combinatorial library obtained is intended for a discovery of new physiologically active compounds.

Highly effective computer-aided (virtual) and real biological screening over quinoline derivatives is described, which has led to the discovery of a new structural class of caspase-3 inhibitors. This enzyme (belonging to the group of cysteine proteases) is a promising therapeutically-significant biological target that is involved in the development of various pathological states in the human organism. The virtual screening method is based upon evaluation of a target-specific profile of compounds by means of a special algorithm intended for the analysis of multiparametric data arrays (self-organizing Kohonen maps). Using this approach, it is possible to carry out directed selection of compounds for a targeted synthesis. The biological screening among synthesized compounds led to a series of new effective inhibitors of caspase-3, the most active of which possess effective inhibiting concentrations in the range of IC50 = 4–30 nM. The nonpeptide nature of the new chemotype offers potentially favorable pharmacokinetic parameters, while its belonging to large libraries (obtained by means of parallel combinatorial synthesis in solution) facilitates the subsequent optimization of active compounds.