Atypical steroid-like analogue of abiraterone, an inhibitor of androgen biosynthesis, was synthesized and characterized by X-ray diffraction analysis. The in vitro study of the compound by differential spectrophotometric titration revealed its ability to bind to truncated CYP17A1 (D 2-19 variant) in a type II fashion through nitrogen coordination with lower affinity than that of abiraterone, but still in nanomolar concentration range (KD approximate to 187 nM). The significant spectral response (DAmax) value suggests that the new compound effectively targets the conformational ensemble of CYP17A1 accessible for ligand binding.

The structures of isoxazole-containing cyclovinylogues of the intracellular fructose transporter protein GLUT5 inhibitor, N-(4-methylsulfonyl-2-nitrophenyl)benzo[d][1,3]dioxol-5- amine (MSNBA) were designed. The target substituted 3,4,5-isoxazoles were synthesized using a method for converting isoxazole-containing enamines to nitriles by their treatment with tert-butyl nitrite in the presence of boron trifluoride etherate. Primary bioassay demonstrated the ability of the target compounds to inhibit the proliferation of chronic myelogenous leukemia cells K562 in medium containing fructose or glucose.

New documents from the archival fund of Academician N.S. Zefi rov in the Archive of the Russian Academy of Sciences are presented. They allow to trace his relationship with his mentor, Professor Yu.K. Yuryev of Moscow University.

1,1-Dibenzyl-3-(1-benzyl-1 1H-pyrazol-4-yl)-2-methylisothioureas containing structural elements both of known antioxidants and glutamate receptor modulators were proposed as compounds with a dual mode of biological action, namely the antioxidant activity and the ability to influence the glutamatergic signaling system. The target compounds were synthesized by the reaction of substituted 4-amino-1-benzylpyrazoles with thiophosgene followed by the condensation of the resulting 1-benzyl-4-isothiocyanato-1H-pyrazoles with dibenzylamine and the subsequent S-methylation of the resulting thioureas. 1,1-Dibenzyl-3-[1-(3,4-dichlorobenzyl)- and 1,1-dibenzyl-3-[1-(2,4-dichlorobenzyl)-1H-pyrazol-4-yl]-2-methylisothioureas were found to have a moderate ability to protect neuroblastoma cells against the toxic effect of hydrogen peroxide, making these compounds interesting for further study of the modulatory activity toward glutamate receptors.

Pyridine-containing amides of rimantadine (1-(1-adamantyl)ethylamine) were synthesized by the amidation of rimantadine hydrochloride by the corresponding acids in the NEt3—N,N′-dicyclohexylcarbodiimide (DCC)—4-(N,N-dimethylamino)pyridine (DMAP) system as the analogues of previously described antiviral compounds 1-adamantylmethyl-5-aminoisoxazole-3-carboxylate and N-[5-(thien-2-yl)isoxazol-3-yl]methyladamantane-1-amine. The spectrum of antiviral activity against the rimantadine-resistant A/PR/8/34 strain of influenza A virus, tick-borne encephalitis virus (TBEV) strain Absettarov (European subtype), yellow fever virus (YFV) vaccine strain 17D, and West Nile virus (WNV) strain Strix nebulosa-12 was studied. The structure—activity relationships were discussed. Synthesized compounds efficiently inhibited the reproduction of TBEV and WNV. N-[1-(Adamantan-1-yl)ethyl]picolinamide efficiently inhibited the reproduction of enveloped viruses with both type I (influenza) and type II (flaviviruses) fusion proteins. The antiviral activity against the rimantadine-resistant influenza virus A/PR/8/34 and a low cytotoxicity (high selectivity index) were revealed for N-[1-(adamantan-1-yl)ethyl]-isonicotinamide.

Steroid dimers of natural and synthetic origin possess an unusual and complex molecular architecture that may lead to the realization of peculiar effects in biological systems, in particular in different cancer cell lines. In the present work, diastereoselective ring-opening of mono- and polyoxiranes, containing a cyclooctane core, by azide-anion was performed to yield a series of azidoalcohols with different types of symmetry. The products were involved in copper-catalyzed azyde-alkyne cycloaddition (CuAAC) reaction with ethinylestradiol and ethinyltestosterone, and the resulting steroids and steroid dimers with triazole linkers were screened for their antiproliferative activity via (3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl tetrazolium bromide) assay. All the compounds revealed cytotoxicity toward several cancer cell lines. The effect of the most potent compound, containing two estradiol moieties, on the microtubules (MT) dynamics was investigated by immunofluorescent microscopy. The disruption of the majority of interphase cell cytoplasmic MT and mitotic event disturbances in the presence of the studied compound were observed. The latter effect caused the appearance of numerous multinucleated cells.

The synthesis of homodimeric bis-esters of abiraterone (an inhibitor of androgens synthesis used for treatment of prostate cancer) as a novel depot form of the drug intended for parenteral administration has been undertaken. The conjugate with succinic linker has been synthesized, while only mono-esters of malic and citric acid were obtained. The target ‘twin’ demonstrated excellent characteristics in preliminary biotests, proving the concept of long-lasting depot-prodrug.

Series of 1,3-disubstituted ureas and diadamantyl disubstituted diureas with fluorinated and chlorinated adamantane residues were shown to inhibit human soluble epoxide hydrolase (sEH) with inhibition potency ranging from 40 pM to 9.2 nM. The measured IC50 values for some molecules were below the accuracy limit of the existing in vitro assays. Such an increase in activity was achieved by minimal structural modifications to the molecules of known inhibitors, including 4-[trans-4-(1-adamantylcarbamoylamino)cyclohexyl]oxybenzoic acid. For the chlorinated homologue of the latter the sharp jump in inhibitory activity can be (according to molecular dynamics data) the result of interactions - Cl-pi interaction. Considering the extremely high inhibitory activity, acceptable solubility and partial blockage of metabolically sensitive centres in their structures, some compounds are of interest for further in vivo biotesting.

Esters of podophyllotoxin and epipodophyllotoxin with 4-(1,3-dioxo-1,3-dihydroisoindol-2-yl)butanoic and (4 R )- N -( tert -butoxycarbonyl)-1,3-thiazolidine-4-carboxylic acids were synthesized. The obtained esters are less lipophilic analogs of the known podophyllotoxin esters. Two new compounds were found to demonstrate selective cytotoxicity against cancer cells in the mixed culture of lung carcinoma cells (A549) and noncancerous lung fibroblasts (VA13). Podophyllotoxin ester with (4 R )-1,3-thiazolidine-4-carboxylic acid moiety was also synthesized. This compound like its pyrrolidine analog was found to be nonselective but in contrast two orders of magnitude less active. Selectivity against cancer cells in combination with acceptable lipophilicity of the podophyllotoxin and epipodophyllotoxin esters bearing the tert -butoxycarbonylthiazolidine moiety makes these compounds promising for further in vitro and in vivo evaluation.

Structural optimization of butyrylcholinesterase inhibitors, 5-bromomethyl- and 5-iodomethyl-N,N-disubstituted 2-aminothiazolines, led to a series of their annulated bicyclic analogues, obtained by intramolecular cyclization of cycloalkenylthioureas. The most active compound in this series, cyclohepta[d]thiazol-2-amine, is a mixed-type butyryl-cholinesterase inhibitor with IC50 = 130 nm, highly selective compared to acetylcholinesterase and non-toxic at 100 μm concentrations.

A series of podophyllotoxin and epipodophyllotoxin esters with methylisoxazole fragments containing a halogen atom or a nitro group at position 4 of the heterocycle was synthesized. The starting isoxazolecarboxylic acids were obtained by bromination, iodination, or nitration of 5-methylisoxazole-3-carboxylic acid, which then were converted to the target esters by esterification in the DCC/DMAP or EDC/DMAP system. The results of molecular docking of podophyllotoxin and epipodophyllotoxin esters with the iodine-containing isoxazole derivatives predicted their ability to bind to tubulin and topoisomerase II, respectively, and do not exclude the possibility of the formation of halogen bonds with target proteins. The primary bioscreening showed that all compounds obtained at a concentration of 100 nmol L-1 caused a decrease in the number of A549 and VA13 cells by 40-60% after 72 h of treatment.

Tubulin-targeting agents attract undiminished attention as promising compounds for the design of anti-cancer drugs. Verubulin is a potent tubulin polymerization inhibitor, binding to colchicine-binding sites. In the present work, a series of verubulin analogues containing a cyclohexane or cycloheptane ring 1,2-annulated with pyrimidine moiety and various substituents in positions 2 and 4 of pyrimidine were obtained and their cytotoxicity towards cancer and non-cancerous cell lines was estimated. The investigated compounds revealed activity against various cancer cell lines with IC50 down to 1–4 nM. According to fluorescent microscopy data, compounds that showed cytotoxicity in the MTT test disrupt the normal cytoskeleton of the cell in a pattern similar to that for combretastatin A-4. The hit compound (N-(4-methoxyphenyl)-N,2-dimethyl-5,6,7,8-tetrahydroquinazolin-4-amine) was encapsulated in biocompatible nanocontainers based on Ca2+ or Mg2+ cross-linked alginate and it was demonstrated that its cytotoxic activity was preserved after encapsulation.

Two bicyclic annulated isothiourea derivatives were synthesized using as a key stage either the reaction of isothiocyanate halide with sodium sulfide or cyclization of unsaturated thiourea in the presence of bromine. X-ray molecular structure of N-[(3aSR,7aRS,Z)-hexahydro-1,3-benzothiazol-2(3H)-ylidene]glycine was determined. The conjugate of colchicine with [(3aR,5S,6aS)-2-(tert-butylamino)-3a,5,6,6a-tetrahydro-4H-cyclopenta[d]thiazol-5-yl]methanol obtained demonstrated pronounced cytotoxic effect on cancer cells.

The conjugate of 2-methoxyestradiol, a ligand for the cell protein tubulin, with two molecules of chlorambucil, known as a DNA-alkylating agent, is capable of blocking the dynamics of tubulin-based microtubules at concentrations of 10–100 µmol L−1, by stabilizing them without changing their structure. Three analogs of this conjugate, which do not contain chloroethylamino and/or methoxy groups at C(2), were synthesized. At these concentrations, these analogs have another, inhibitory or combined, effect on the microtubule polymerization. Based on the molecular modeling results, the binding site of the initial conjugate in tubulin was proposed.

Immunofluorescent microscopy of cancer cells A549 treated with novel alicyclic (mostly bridged) podophyllotoxin C4-esters at different concentrations gave evidence that the 'curling' of microtubules occurred at one of the first steps of their depolymerisation. Molecular dynamics study revealed the differences in curved conformations of tubulin dimer in a complex with adamantane-comprising ester and in a complex with podophyllotoxin.

The application of non-planar scaffolds in drug design allows for the enlargement of the chemical space, and for the construction of molecules that have more effective target–ligand interactions or are less prone to the development of resistance. Among the works of the last decade, a literature search revealed spirothiazamenthane, which has served as a lead in the development of derivatives active against resistant viral strains. In this work, we studied the novel molecular scaffold, which resembles spirothiazamenthane, but combines isoxazoline as a heterocycle and cyclooctane ring as a hydrophobic part of the structure. The synthesis of new 3-nitro- and 3-aminoisoxazolines containing spiro-fused or 1,2-annelated cyclooctane fragments was achieved by employing 1,3-dipolar cycloaddition of 3-nitro-4,5-dihydroisoxazol-4-ol 2-oxide or tetranitromethane-derived alkyl nitronates with non-activated alkenes. A series of spiro-sulfonamides was obtained by the reaction of 3-aminoisoxazoline containing a spiro-fused cyclooctane residue with sulfonyl chlorides. Preliminary screening of the compounds for antiviral, antibacterial, antifungal and antiproliferative properties in vitro revealed 1-oxa-2-azaspiro[4.7]dodec-2-en-3-amine and 3a,4,5,6,7,8,9,9a-octahydrocycloocta[d]isoxazol-3-amine with activity against the influenza A/Puerto Rico/8/34 (H1N1) virus in the submicromolar range, and high values of selectivity index. Further study of the mechanism of the antiviral action of these compounds, and the synthesis of their analogues, is likely to identify new agents against resistant viral strains.

A series of novel antimitotic agents was designed using the replacement of heterocyclic cores in two tubulin-targeting lead molecules with the acylated 4-aminoisoxazole moiety. Target compounds were synthesized via heterocyclization of β-aryl-substituted vinylketones by tert-butyl nitrite in the presence of water as a key step. 4-Methyl-N-[5-methyl-3-(3,4,5-trimethoxyphenyl)isoxazol-4-yl]benzamide (1aa) was found to stimulate partial depolymerization of microtubules of human lung carcinoma A549 cells at a high concentration of 100 µM and to totally inhibit cell growth (IC50  = 0.99 µM) and cell viability (IC50  = 0.271 µM) in the nanomolar to submicromolar concentration range. These data provide evidence of the multitarget profile of the cytotoxic action of compound 1aa. The SAR study demonstrated that the 3,4,5-trimethoxyphenyl residue is the key structural parameter determining the efficiency both towards tubulin and other molecular targets. The cytotoxicity of 3-methyl-N-[5-methyl-3-(3,4,5-trimethoxyphenyl)isoxazol-4-yl]benzamide (1ab) to the androgen-sensitive human prostate adenocarcinoma cancer cell line LNCaP (IC50  = 0.301 µM) was approximately one order of magnitude higher than that to the conditionally normal cells lines WI-26 VA4 (IC50  = 2.26 µM) and human umbilical vein endothelial cells (IC50  = 5.58 µM) and significantly higher than that to primary fibroblasts (IC50  > 75 µM).

In the present work we have studied a novel conjugate of the DNA alkylating agent chlorambucil with podophyllotoxin, a ligand of the colchicine binding site in tubulin. The target compound was obtained by Steglich esterification of podophyllotoxin with the percentage yield of 41%. Results of biotesting carried out on the carcinoma A549 cell line revealed that at a concentration of 2 μM the conjugate caused full depolymerization of microtubules without any other effect on free tubulin. The conjugate inhibited proliferation (IC50=135±30 nM) and growth (EC50=240±30 nM) of A549 cells. The data of computer molecular docking of the novel compound into the 3D model of the colchicine binding site in α,β-tubulin and molecular dynamics modelling allowed to explain the observed difference in effects of chlorambucil-podophyllotoxin and chlorambucil-colchicine conjugates on microtubules.