Sergei F Vasilevsky

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The nature of products in the diazotization of 1-amino-2-acetylenyl-9,10-anthraquinones strongly depends on the nature of substituents at both the alkyne and at the anthraquinone core. Donor substitution (NHAr, OH) at the fourth position stabilizes the diazonium salt at C1, decelerating electrophilic cyclization at the arylethynyl substituent at C2. This(More)
The reaction of diaryl ketoalkynes with 1,2-diamino ethane leads to the full scission of the triple bond with the formation of acetophenone and imidazoline fragments. In this transformation, one of the alkyne carbons undergoes formal reduction with the formation of three C-H bonds, whereas the other carbon undergoes formal oxidation via the formation of(More)
This work analyzes multiple new reaction pathways which originate from intramolecular reactions of activated alkynes with the appropriately positioned multifunctional hemiaminal moiety. Combination of experimental substituent effects with Natural Bond Orbital (NBO) analysis revealed that alkyne polarization controls partitioning between these cascades. A(More)
Reactions between Cu(hfac)2 and nitronyl nitroxide biradicals 1,4-bis[4-(4,4,5,5-tetramethyl-3-oxide-1-oxyl-4,5-dihydro-1H-imidazol-2-yl)pyrazol-1-yl]butane (L4) and 1,8-bis[4-(4,4,5,5-tetramethyl-3-oxide-1-oxyl-4,5-dihydro-1H-imidazol-2-yl)pyrazol-1-yl]octane (L8) gave respectively a framework compound [Cu(hfac)2]2L4 and a layered polymer compound(More)
New approach to synthesis of analogs of natural Combretastatin A-4 based on interaction of α-acetylenic ketones with secondary amines (diethyl amine, pyrrolidine, piperidine, morpholine) is offered. Unknown analogs of Combretastatin A-4 with β-aminovinylcarbonyl bridges are received earlier. Anti-inflammatory activity of the received connections is studied.
A new approach to the synthesis of natural combretastatin A-4 analogues based on the interaction of α-acetylenic ketones with secondary amines (diethyl amine, pyrrolidine, piperidine, morpholine) was proposed. Previously unknown analogues of combretastatin A-4 containing the β-aminovinylcarbonyl bridges were synthesized. Anti-inflammatory activity of the(More)
The EtONa-mediated reaction of peri-R-ethynyl-9,10-anthraquinones with thiourea yields 2-R-7H-dibenzo[de,h]quinolin-7-ones and 2-R-anthra[2,1-b]thiophene-6,11-diones. Although 2-R-7H-dibenzo[de,h]quinolin-7-ones were observed previously in reactions with other N-centered nucleophiles (hydrazine, guanidine, and urea), the formation of(More)
Reductive dimerization of acetylenic anthraquinones provides synthetic access to flexible nonplanar polyaromatics with a tetracenedione core. In solution, these nonplanar, contorted polycycles exist as equilibrating mixtures of two symmetric conformers. The fused tetracenediones are easily reduced and exhibit rich electrochemical behavior.
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