A. V. Lipeeva

Synthesis of 1H-1,2,3-triazole linked aryl(arylamidomethyl) - dihydrofurocoumarin hybrids and analysis of their cytotoxicity.

A series of 2-(4-R-triazolyl)substituted 3-oxo-2,3-dihydrofurocoumarins have been synthesized by a regioselective cycloaddition of 2-azidooreoselone 1 or 2-azido-9-[(4-methylpiperazin-1-yl)methyl]oreoselone 2 with various alkynes in the presence of Cu(II)/ascorbate in water/methylene chloride reaction medium. The structure of 2-azidooreoselone was established by X-ray structure analysis. The cytotoxicity of 2-substituted dihydrofurocoumarins was determined against three cancer cell lines (CEM-13, MT-4, U-937) using the conventional MTT assays. Among the tested molecules, most of the analogs displayed better cytotoxic activity then the parent natural furocoumarin peucedanin 3. The activity and selectivity to the cell line increased even further in the series of 2-(4-{2,3-dihydrobenzo[b][1,4]dioxine}triazolyl)-3-oxo-2,3-dihydrofurocoumarins and 2-(4-aryltriazolyl)-3-oxo-2,3-dihydrofurocoumarins having the (4-methylpiperazin-1-ylmethyl) substituent in the 9-th position. The most active compound 20 contain the 4-hydroxy-3-methoxybenzamidomethyl substituent in the 4-th position at the triazole ring of 2-(triazol-1-yl)dihydrofurocoumarins. The obtained 2-triazolyl substituted dihydrofurocoumarins were studied as inhibitors of phosphodiesterase (PDE-4B) using docking experiments. As a result of virtual screening 3 compounds are selected based on minimum binding energy. The interactions of the most active compound and amino acid residues in the binding site were studied.

Synthesis and cytotoxic activity of a new group of heterocyclic analogues of the combretastatins.

A series of new analogs of combretastatin A-4 (CA-4, 1) with the A or B-ring replaced by a 3-oxo-2,3-dihydrofurocoumarin or a furocoumarin residue have been designed and synthesized by employing a cross-coupling approach. All the compounds were evaluated for their cytotoxic activity with respect to model cancer cell lines (CEM-13, MT-4, U-937) using conventional MTT assays. Structure-activity relationship analysis reveals that compounds 2, 3, 6–8 in which the (Z)-styryl substituent was connected to the 2-position of the 3-oxo-2,3-dihydrofurocoumarin core, demonstrated increased potency compared to 3-(Z)-styrylfurocoumarins 4, 5, 9–11. The methoxy-, hydroxyl- and formyl- substitution on the aromatic ring of the (Z)-styryl moiety seems to play an important role in this class of compounds. Compounds 2 and 3 showed the best potency against the CEM-13 cell lines, with CTD50 values ranging from 4.9 to 5.1 μM. In comparison with CA-4, all synthesized compounds presented moderate cytotoxic activity to the T-cellular human leucosis cells MT-4 and lymphoblastoid leukemia cells CEM-13, but most of them were active in the human monocyte cell lines U-937.

Study of plant coumarins. 12*. Synthesis of 2-(1,2,3-triazolyl)-modified furocoumarins

Bromooreoselone reacted with sodium azide to give 2-azidooreoselone, which was highly reactive in a catalytic Huisgen reaction with various terminal alkynes. These reactions yielded 4-substituted 2-(triazol-1-yl)furocoumarins. The reaction of oreoselone azide with dimethyl acetylene-1,2-di-carboxylate gave 2-[(4,5-dimethoxycarbonyl)triazolyl]oreoselone and reaction with 7-ethynyl-6-methoxycarbonylcoumarin gave 1,4-dicoumarin-substituted 1,2,3-triazole.

Study of plant coumarins: X. Peurutenicin triflate in cross-coupling reactions

By Suzuki cross-coupling reaction of peurutenicin triflate with arylboric, furanylboric, pyridinylboric, and indolylboric acids the corresponding 7-aryl(hetaryl)coumarins were synthesized. The high activity of hetaryl-substituted boric acids in the Suzuki reaction was observed. Heck reaction of 7-O-trifluoromethylsulfonylpeur utenicin with terminal olefins (styrene, vinylpyridines, vinylpyrazine, vinyltriazole) was used to prepare (E)-7-[aryl(hetaryl)vinyl]coumarins. The dependence of reaction products yield on the nature of the catalytic system was found.

Plant coumarins: VI. Synthesis of 3-vinylfurocoumarin derivatives based on oreoselone

Palladium-catalyzed Heck reaction of oreoselone trifluoromethanesulfonate with various terminal alkenes (methyl acrylate, styrene, vinylpyridines, N-vinylpyrrole, and N-vinyl-1,2,4-triazole) led to the formation of the corresponding (E)-3-vinyl-7H-furo[3,2-g]chromen-7-ones. The yield was found to depend on the catalytic system and initial olefin structure.

Plant coumarins: XIII. Synthesis of 2,3,9-trisubstituted furocoumarins

Peucedanin reacted with methylideneiminium salt generated in situ from N,N,N′,N′-tetramethylmethanediamine and acetyl chloride to give 2-(dimethylaminomethyl)oreoselone. Reactions of peucedanin with aminomethylating agents generated in situ from formaldehyde and dimethylamine, N-methylpiperazine, or N-Boc-piperazine in boiling methanol smoothly afforded the corresponding 9-aminomethyl derivatives whose hydrolysis produced 9-aminomethyl-substituted oreoselones. 2,3,9-Trisubstituted linearly fused furocoumarins were synthesized by reactions of 9-substituted oreoselone trifluoromethanesulfonates with arylboronic acids.

Plant coumarins: VIII. Suzuki reaction in the synthesis of 3-aryl(hetaryl)furocoumarins

Suzuki cross coupling of oreoselone trifluoromethanesulfonate with substituted phenyl- and hetarylboronic acids in the presence of palladium complexes with uni- and bidentate ligands gave the corresponding 3-substituted furocoumarins.

The flavanone pinostrobin in the synthesis of coumarin-chalcone hybrids with a triazole linker

The reaction of flavanone pinostrobin with dibromoalkanes in acetone in the presence of potassium carbonate followed the path of retro-Michael addition – О-alkylation and resulted in the formation of the respective 2-(bromoalkoxy)chalcones. Treatment of the latter with sodium azide gave the respective azides, which were highly active in the Сu-catalyzed 1,3-dipolar cycloaddition reaction. The reaction of these azides with 6-substituted 7-ethynylcoumarins gave coumarin-chalcone hybrids containing a 1,2,3-triazole linker.

Study of Plant Coumarins: XIV. * Catalytic Amination of 7-Hydroxycoumarin Derivatives

Catalytic amination of 7-hydroxy-6-cyanocoumarin or 7-hydroxy-6-methoxycarbonylcoumarin triflates with substituted anilines, isoquinolin-5-amine, 1H-pyrazol-3-amine, or amino acids of penicillin series affords the corresponding 7-(N-substituted) aminocoumarins. In the amination of the mentioned triflates and also of peuruthenicine tosilate with 2-(piperidin-1-yl)aniline the catalytic system Pd(OAc)2-BINAP has been efficient.

Plant coumarins: VII. Amination of oreoselone trifluoromethanesulfonate

Amination of oreoselone trifluoromethanesulfonate with N-substituted piperazines, anabasine, aniline derivatives, quinolin- and isoquinolinamines, and amino acids of the penicillin and cephalosporin series in the presence of palladium complexes gave the corresponding N-substituted 3-aminofurocoumarins. The yield of the amination products depended on the catalytic system and base used.