Pentakis-thiacalix[4]Arenes with Nitrile Fragments: Receptor Properties toward Cations of Some s-and d-metals and Self-assembly of Nanoscale Aggregates

Pentakis-thiacalix[4]arenes containing thiacalix[4]arene fragments in cone, partial cone and 1,3-alternate conformations as their central core have been obtained. Their interaction with cations of s- and d-metals gives supramolecular assemblies whose composition depends on the conformation of pentakis-thiacalix[4]arenes and the nature of the ‘guests’.     

Mass spectrometric investigation of the side-arm lariat effect of ortho- and para-methoxyphenoxymethyl-15-crown-5 in the gas phase

Mixtures of unsubstituted 15-crown-5 and its analogues containing ortho- and para-methoxyphenoxymethyl substituents with sodium salts were investigated by matrix assisted laser desorption/ionization (MALDI) mass spectrometry. Peaks of cationized molecules [M+Na]⁺ and cluster ions [2M+2Na+An]⁺, where M is the crown ether molecule and An is monobasic acid anion, were observed in the mass spectra. It was shown that an increase of the shielding degree of the sodium cation in complexes with crown ethers, i.e., the lariat effect, led to a significant decrease in the intensity of peaks of the cluster ions.     

α-Amino acetals containing a phosphonate or phosphine oxide group. Synthesis and reactions with resorcinols

New α-amino acetals containing a phosphonate or phosphine oxide group were synthesized by the Kabachnik-Fields reaction in the ternary system amino acetal-paraformaldehyde-dialkyl phosphonate (or dialkylphosphine oxide). Condensation of dialkyl (2,2-dimethoxyethylamino)methylphosphonates with resorcinol and its derivatives in ethanol in the presence of hydrochloric acid, apart from the corresponding 2,2-bis(polyhydroxyphenyl) ethylammonium salts, gave 2,5-bis(polyhydroxyphenyl)-1,4-bis[(dialkoxyphosphoryl)methyl]-piperazines. Dialkyl[(2,2-dimethoxyethylamino)methyl]phosphine oxides (Alk = C₈H₁₇, C₁₀H₂₁) did not react with resorcinol derivatives under similar conditions, and analogous ammonium salts were obtained by heating the reactants in boiling trifluoroacetic acid.     

Polyfused nitrogen-containing heterocycles 23. Methyl 4-hydroxy-3-phenyl-5-phenyl(alkyl)-2-phenyliminoselenazolidine-4-carboxylates and selenazolo[3,4-a]quinoxalin-4(5H)-one derivatives on their basis

Russian Chemical Bulletin - Condensation of methyl phenyl(alkyl)halopyrotartrates with N,N′-diphenylselenourea leads to the formation of methyl...     

Six-membered cyclic semiaminal as intermediate in the synthesis of thiazoles from thiosemicarhazide and α-haloketones

Cyclization of thiosemicarbazide with methyl 3-chloro-2-oxo-3-phenylpropionate in MeCN results in 5-hydroxy-2-imino-5-methoxycarbonyl-6-phenylperhydro-1,3,4-thiadiazine. The structure of the product has been confirmed using spectral (IR,¹H,¹³C,¹³C{¹H} NMR) methods and chemical transformations.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1962–1965, November, 1993.     

Synthesis and Antioxidant Activity of Sterically Hindered Phenol Derivatives of Carboxy- and Sulfobetaines

New multifunctional antioxidants based on carboxy- and sulfobetaines with sterically hindered phenol fragments were synthesized. The antioxidant capacity of the compounds determined in the reactions of their oxidation by electrogenerated bromine is comparable to that of ascorbic acid and ionol.     

A novel one-step efficient method for the synthesis of tetrahydroindoles from 1-(1-pyrrolidino)cyclohexene and chloropyruvates

A highly efficient, one-step, versatile method for the synthesis of tetrahydroindoles has been developed on the basis of new ring formation in the reactions of 1-(1-pyrrolidino)cyclohexene with chloropyruvates.     

An efficient one-step method for the synthesis of 2-(indolizin-2-yl)benzimidazoles from quinoxalinones and α-picoline via a novel rearrangement

A highly efficient one-step and versatile method for the synthesis of 2-(indolizin-2-yl)benzimidazoles has been developed on the basis of the novel ring contraction of 3-arylchloromethyl- and alkylchloromethylquinoxalin-2-ones with α-picoline.