S(N)(H) approach in the synthesis of nitronyl nitroxides.

We show that the S(N)(H) approach opens up new possibilities in the synthesis of hetaryl-substituted nitronyl nitroxides. The reaction of 4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl lithium salt with pyridine-, pyrimidine-, pyrazine-, isoquinoline-, phthalazine-, quinoxaline-, and 1,2,4-triazine-N-oxides readily gives rise to the corresponding paramagnetic hetarenes. The reaction of this salt with quinoxaline-1,4-dioxide enabled the synthesis of the first nitronyl nitroxide biradical with two spin-labeled fragments in the vicinal positions of the heteroaromatic cycle; the persistent biradicals of this type were not known earlier.

The tert-amino effect in heterocyclic chemistry. Synthesis of spiro heterocycles.

The tert-amino reaction effect was examined. A new method to synthesize spiro heterocycles is presented. It was shown that the "tert-amino effect" could be applied to the formation of spiro-fused heterocycles.

A novel three-component reaction designed by the combinatorial method: heteroarenes, isothiocyanates and isocyanides.

The novel three-component reaction of isoquinoline with isothiocyanates and isocyanides leads to a variety of new imidazoisoquinolines. The zwitterionic ground state of these new ring systems is established by means of NMR and X-ray analysis. Use of phthalazine instead of isoquinoline gives access to imidazole annulated phthalazines.

Ugi reaction in aqueous solutions: a simple protocol for libraries production.

A reaction between levulinic acid, isocyanides and primary amines has been examined in distilled water and in surfactants solutions. It is demonstrated that the reaction gives good results at the different concentrations including one well above the solubility limit. A simple and eco-friendly protocol for libraries production is described.

Reaction of 5-halo-1,2,3-thiadiazoles with aliphatic diamines. Synthesis and intramolecular cyclization of bis(1,2,3-triazolyl-1,2,3-thiadiazolyl)sulfides.

Bis[1,2,3]triazolo[1,5-f:5',1'-b][1,3,6]thiadiazepine and [1,5-g:5',1'-b][1,3,7]thiadiazocine ring systems have been synthesized from 5-halo-1,2,3-thiadiazoles and aliphatic diamines. We have found that the last step of the process is the cyclization of initially formed bis(1,2,3-triazolyl-1,2,3-thiadiazolyl)sulfides. The structures of the intermediates and products were supported by different NMR spectroscopic methods (1H coupled 13C NMR, 2D HETCOR, HMBC and 1D INADEQUATE experiments) and mass spectrometry.

Reactions of 5-mercaptoazoles and pyridine-2-thiones with acetylenic esters. Selectivity of the formation of novel fused thiazin-4-ones and thiazolidin-4-ones.

A systematic study of the reactions of dimethyl acetylenedicarboxylate (DMAD) and methyl propynoate with 5-mercaptoazoles and pyridine-2-thiones has been carried out and as a result, a number of novel imidazo[1,5-b]thiazin-4-ones 6a,b, pyrazolo[1,5-b] thiazin-4-ones 15a-f, imidazo[1,5-b]thiazol-4-ones 7a,b and thiazolo[3,2-a]pyridines 21a-c have been prepared. The influence of the size of the ring of the starting "cyclic" thioamides on the size of the fused ring in the reaction products has been established. The preferred formation of a six-membered thiazine ring took place in the reactions of 5-mercaptoazoles.

[Model for the cell biomembrane electric potential during active transport of various ions].

A model of a stationary electrical potential on biomembrane was created. This model takes into account conformational changes in transport ATPase. N positive ions are transported simultaneously by the system of active transport.

Ab initio and density functional calculations on the pericyclic vs pseudopericyclic mode of conjugated nitrile ylide 1, 5-electrocyclizations.

Ab initio (MP2/6-311+G and MP4(SDTQ)/6-311+G//MP2/6-311+G) and density functional (B3LYP/6-311+G) calculations on the ring closure reactions of conjugated nitrile ylides 1a-e, 3, and 6 to the corresponding oxazoles 2a, 5, 7, and 8; thiazoles 2b and 4; imidazole 2c; and pyrroles 2d and 2e, respectively, are reported. Vinyl nitrile ylides 1d and 1e cyclize with a substantially higher barrier than nitrile ylides containing a heteroatom. Geometric features as well as electronic structures as obtained by NBO analysis are indicative of a pericyclic, monorotatory 1, 5-electrocyclization of 1d and 1e.

[Reaction of acylation of the antineoplastic antibiotic bleomycetin].

The reaction of benzoylation of bleomycetin, a glycopeptide antibiotic, and its cuprum complex was studied with the chloranhydride and carbodiimide methods. Acylation of the antibiotic cuprum complex by an equivalent quantity of benzoyl chloride resulted in formation of a mixture of mono- and disubstituted derivatives while with the use of a 3-fold excess of chloranhydride it was possible to obtain dibenzoylbleomycetin as a sole reaction product. Interaction of the bleomycetin cuprum complex with activated benzoic ether resulted in formation of a product monosubstituted by the antibiotic spermidine fragment.