Igor A. Ushakov

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A facile one-pot synthesis of 3-trifluoromethylated piperazin-2-ones has been achieved by the treatment of trifluoromethyl 2-bromo enones with N,N'-disubstituted ethylenediamines in trifluoroethanol. The mechanism of this unexpected reaction is discussed in terms of multistep processes involving formation of captodative aminoenone as a key intermediate. The(More)
According to the (1)H, (13)C and (15)N NMR spectroscopic data and ab initio calculations, the strong N--H...O intramolecular hydrogen bond in the Z-isomers of 2-(2-acylethenyl)pyrroles causes the decrease in the absolute size of the (1)J(N,H) coupling constant by 2 Hz in CDCl(3) and by 4.5 Hz in DMSO-d(6), the deshielding of the proton and nitrogen by 5-6(More)
Dynamic NMR of 1-(methylsulfonyl)-3,5-bis(trifluoromethylsulfonyl)-1,3,5-triazinane reveals the existence of three conformers and two dynamic processes: ring inversion and rotation about the N-S bond, both processes having DeltaG(++) = 13.5 kcal/mol. An unprecedented large reverse Perlin effect (J(CHax) > J(CHeq)) was found experimentally and calculated(More)
In the (13) C NMR spectra of methylglyoxal bisdimethylhydrazone, the (13) C-5 signal is shifted to higher frequencies, while the (13) C-6 signal is shifted to lower frequencies on going from the EE to ZE isomer following the trend found previously. Surprisingly, the (1) H-6 chemical shift and (1) J(C-6,H-6) coupling constant are noticeably larger in the ZE(More)
Ketones with bulky aromatic, heteroaromatic and ferrocene substituents react with acetylene in the presence of a KOH/DMSO super-base suspension (90 °C, 15 min) to give polysubstituted furans in up to 86 % isolated yields in a one-pot fashion. This assembly of the furan scaffold involves a domino sequence in which one molecule of ketone reacts with two(More)
1-Substituted imidazoles undergo exceptionally facile stereoselective ring opening under the influence of electron-deficient acetylenes and water (equimolar ratio of the reactants) in MeCN at 45-60 °C without any catalysts to afford functionalized (Z,Z)-1,4-diaza-2,5-dienes, (Z,Z)-propenylaminoethenylformamides, in up to 80% yields. The reaction is(More)
In the acetylenic aldehyde oximes with substituents containing silicon and germanium, the (13)C NMR signal of the C-2 carbon of triple bond is shifted by 3.5 ppm to lower frequency and that of the C-3 carbon is moved by 7 ppm to higher frequency on going from E to Z isomer. A greater low-frequency effect of 5.5 ppm on the C-2 carbon signal and a greater(More)
First examples of direct vinylation of 1-substituted imidazoles at the 2-position of the imidazole nucleus are described. 1-Substituted imidazoles 1a-e are C(2)-vinylated with 3-phenyl-2-propynenitrile (2) at room temperature without catalyst and solvent to afford 3-(1-organyl-1H-imidazol-2-yl)-3-phenyl-2-propenenitriles 3a-e, mainly (c.a. 95%) as(More)