N. G. Kolotyrkina

Synthesis of N-glycyl-β-glycopyranosyl amines, derivatives of natural oligosaccharides — glucose analogs of Lex antigen

Treatment of the natural tri-, tetra-, and pentasaccharides, β-d-Galp-(1→4)-[α-l-Fucp-(1→3)]-d-Glcp, α-l-Fucp-(1→2)-β-d-Galp-(1→4)-[α-l-Fucp-(1→3)]-d-Glcp, and α-l-Fucp-(1→2)-[α-d-GalNAcp-(1→3)]-β-d-Galp-(1→4)-[α-l-Fucp-(1→3)]-d-Glcp, which are glucose analogs of Lex, with ammonium carbamate in aqueous methanol gave the corresponding β-glycopyranosyl amines. After their N-acylation with N-Z-glycine N-hydroxysuccinimidyl ester (Z is benzyloxycarbonyl) with subsequent hydrogenolytic removal of Z-group, corresponding N-glycyl-β-glycopyranosyl amines were obtained in yields up to 70%.

Synthesis of imidazo[4,5-e]thiazolo[2,3-c]-1,2,4-triazine-2,8-diones via a rearrangement of imidazo[4,5-e]thiazolo[3,2-b]-1,2,4-triazine-2,7-diones in the reaction with isatins

An aldol condensation/skeletal rearrangement protocol for the synthesis of 1,3-dialkyl-7-(2-oxo-1,2-dihydro-3H-indol-3-ylidene)-1,3a,4,9a-tetrahydroimidazo[4,5-e]thiazolo[2,3-c]-1,2,4-triazine-2,8(3H,7H)-diones in good to high yields via a one-pot reaction of 1,3-dialkyl-3,3a,9,9a-tetrahydroimidazo[4,5-e]thiazolo[3,2-b]-1,2,4-triazine-2,7(1H,6H)-diones and 1H-indole-2,3-diones (isatins) or through the generation and rearrangement of 1,3-dialkyl-6-(2-oxo-1,2-dihydro-3H-indol-3-ylidene)-3,3a,9,9a-tetrahydroimidazo[4,5-e]thiazolo[3,2-b]-1,2,4-triazine-2,7(1H,6H)-diones has been developed.

Interaction of 16-hydroxymethylidene derivatives of androstane and estrone with thiohydrazides of oxamic acids

Reaction of thiohydrazides of oxamic acids with 16-hydroxymethylidene derivatives of androstane and estrone involves the hydroxymethylidene group and leads to thiohydrazones, which undergo heterocyclization to give 16-(1,3,4-thiadiazol-2-yl)-substituted steroids.

Peculiarities of interaction of H+, Me3C+, and Me3Si+ ions with multifunctional molecules in the gas phase

Peculiarities of interaction of H+, Me3C+, and Me3Si+ ions with functional groups of molecules in the gas phase have been studied. Proton tends to form chelates with virtually all of the functional groups studied, whereas Me3Si+ ions exhibit no capacity for chelation. Using isomeric xylenes as examples it was shown that Me3Si+ ions (unlike Me3C+ ions) experience virtually no steric hindrance when they react with nucleophilic centers. Effects of functional groups present in molecules of nitriles on the generation of [M+Me3C]+ adducts in the gas phase and the Ritter reaction in solution were estimated.

Synthesis and biological activity of oxindolylidene derivatives of imidazo[4,5-e]thiazolo[3,2-b]-1,2,4-triazin-7-ones and imidazo[4,5-e]thiazolo[2,3-с]-1,2,4-triazin-8-ones

Reactions of 1,3-dialkyl-2-thioxo-1,2,3,3a,9,9a-hexahydroimidazo[4,5-e]thiazolo[3,2-b]-1,2,4-triazin-7(6H)-ones with isatin and its derivatives under base catalysis conditions lead to the corresponding 1,3-dialkyl-6(7)-(2-oxoindolin-3-ylidene)derivatives of 2-thioxo-1,2,3,3a,9,9a-hexahydroimidazo[4,5-e]thiazolo[3,2-b]-1,2,4-triazin-7(6H)-one or 2-thioxo-1,2,3,3a,4,9a-hexahydroimidazo[4,5-e]thiazolo[2,3-c]-1,2,4-triazin-8(7H)-one resulting from the aldol-crotonic condensation and skeletal amidine rearrangement of the thiazolotriazine fragment, depending on the amount of added alkali.

Synthesis of novel spiro[indole-3,3′-pyrrolidin]-2(1H)-ones

Diastereoselective [3+2] cycloaddition of azomethine ylide to 1,3-dimethyl-6-(2-oxo-1,2-dihydro-3H-indol-3-ylidene)-3a,9a-diphenyl-3,3a,9,9a-tetrahydroimidazo[4,5-e]thiazolo[3,2-b]-[1,2,4]triazine-2,7(1H,6H)-dione yields hitherto unknown 1,1′,3-trimethyl-3a,9a-diphenyl-3,3a,9,9a-tetrahydrodispiro(imidazo[4,5-e]thiazolo[3,2-b][1,2,4]triazine-6,3′-pyrrolidine-4′,3″-indole)-2,2″,7(1H,1″H)-triones.

Reactions of 17-chloro-16-formylandrosta-5,16-diene with thiohydrazides of oxamic acids

Reactions of thiohydrazides of oxamic acids with 17-chloro-16-formylandrosta-5,16-diene give the corresponding thiohydrazones at the formyl group. Their subsequent reactions with alkali (het)arenethiolates yield 17-het(aryl)thio derivatives, being accompanied by cyclization of the thiooxalylhydrazone fragment into a 1,3,4-thiadiazole ring.

Interaction of trimethylsilyl ions with nitrates of the estrane series in the gas phase

The interaction of trimethylsilyl ions with nitrates of the estrane series affords the adducts [M + SiMe3]+, whose fragmentation proceeds through the elimination of the functional groups either along with the trimethylsilyl residue, or in the form of molecules containing no SiMe3.

Tetramethylsilane as reagent gas: mass spectra of nitrocarboxylic acid esters and nitroalcohols

Nitrocarboxylic acid esters and nitroalcohols react with trimethylsilyl cation in the gas phase under conditions of chemical ionization to form stable [M+SiMe3]+ ions. The pathways of their fragmentation were established and characteristic distinctions in the mass spectra caused by mutual arrangement of functional groups were found.

Specific features of the interaction of methyl ethers of methyl (methyl-α-D-galactopyranoside)uronate with trimethylsilyl ions in the gas phase

Specific features of the interaction between trimethylsilyl ions and methyl (methyl-α-d-galactopyranoside)uronate and its methyl ethers were revealed. It was shown that a hydrogen atom is generated when the trimethylsilyl ion is located at hydroxyl group. This atom migrates over the methoxy and hydroxyl groups toward the glycoside methoxy group, resulting in the formation of [Me+SiMe3−MeOH]+ ions.