N. M. Azancheev

Tautomerism of aza cycles: II. Synthesis and structure of 5-substituted 3-(2-hydroxyethylsulfanyl)-1H-1,2,4-triazoles and their salts. Preference of the 1H,4H-1,2,4-triazolium tautomers

New complexing agents, potentially tautomeric 3-(2-hydroxyethylsulfanyl)-1H-1,2,4-triazole, its 5-methyl-and 5-phenyl-substituted analogs, and some their salts, were synthesized, and their structure was discussed on the basis of the 1H and 13C NMR, IR, and mass spectra, X-ray diffraction data, and published data. In keeping with the rule formulated previously for N-unsubstituted 1,2,4-triazoles having dissimilar substituents, the synthesized compounds were found to exist as 3-(2-hydroxyethylsulfanyl)-5-R-1H-1,2,4-triazole tautomers (3-RA-5-RD-1H-1,2,4-triazoly). They are protonated at the nitrogen atom in position 4 of the triazole ring. The 1H and 13C NMR spectra of these compounds in trifluoroacetic acid suggest the presence of two forms due to equilibrium between the neutral and protonated species. Analysis of the crystallographic data for the triazolium salts and published data showed preference of the 1H,4H-1,2,4-triazolium tautomer.

Jacobsen-type enantioselective hydrolysis of aryl glycidyl ethers. 31P NMR analysis of the enantiomeric composition of oxiranes

The enantioselective partial hydrolysis of a number of racemic aryl glycidyl ethers in the presence of chiral Co(salen)-catalyst was studied. The enantiomeric composition of the isolated (R)-aryl glycidyl ethers was analyzed by 31P NMR using optically active substituted 2-chloro-1,3,2-dioxaphospholanes. A synthesis of β-adrenoblocking agents (S)-toliprolol and (S)-moprolol based on the simultaneously obtained (S)-3-aryloxypropane-1,2-diols was proposed.

Fused nitrogen-containing heterocycles: III. 4-oxo-1-phenyl-4,5-dihydroimidazo [1,5-a]quinoxalines. A retrosynthetic approach

Retrosynthetic analysis of the structure of imidazo[1,5-a]quinoxalines made it possible to develop new convenient procedures for preparation of these compounds by reaction of 3-(α-chlorobenzyl)-1,2-dihydroquinoxalin-2-one with potassium thiocyanate or isocyanate as synthetic equivalent of the two-membered N-ÍC+ building blocks and by reaction of 3-(α-aminobenzyl)-1,2-dihydroquinoxalin-2-one with carbon disulfide, triethoxymethane, aromatic aldehydes, or acetic anhydride as synthetic equivalent of the one-membered RC3+ synthon.

Synthesis of aryloxy-substituted 1,2,5-thiadiazoles by the Ullmann reaction

Abstract3-Aryloxy-1,2,5-thiadiazoles were synthesized by the Ullmann reaction either from 3-chloro-1,2,5- thiadiazoles and phenols having donor substituents or from 3-hydroxy-1,2,5-thiadiazoles and chlorobenzenes containing acceptor substituents.

Reaction of Phenylenedioxytrihalogenophosphoranes with Arylacetylenes. Synthesis and Spatial Structure of the Derivatives of 2-Oxo-4-Aryl-5,6-Benzo-1,2-Oxaphosphorin-2-Enes

New method of synthesis of six-membered heterocycles – 2-R-2-oxo-4-aryl-2H-benzo[e][1,2]-oxaphosphorin-3-enes has been developed. It includes the interaction of arylenedioxy trihalogenophosphoranes with arylacetylenes. The formation of phosphoryl group and P-C bond, ipso-substitution of the aromatic oxygen and halogenation of the benzene ring take place in this unusual reaction. The influence of the phosphorane structure on synthetic result is discussed. If both para positions at benzene ring of the phosphorane are occupated by halogens, the evolving of halogen molecule occurs. The structures of 2-R-2-oxo-4-aryl-2H-benzo[e][1,2]-oxaphosphorin-3-enes are determined by X-ray analysis.

Reactions of phenylenedioxytrihalophosphoranes with arylacetylenes. 5. Regiochemistry of the reaction of 2,2,2-trichloro-5-chlorocarbonylbenzo[d]-1,3,2-dioxaphosphole with phenylacetylene. Synthesis and three-dimensional structures of 6-alkylaminocarbonyl-2-oxo-4-phenylbenzo[e]-1,2-oxaphosphorinine derivatives

Abstract2,2,2-Trichloro-5-chlorocarbonylbenzo[d]-1,3,2-dioxaphosphole was prepared for the first time by the reaction of protocatechuic acid with phosphorus pentachloride or trichloride followed by chlorination. According to the results of NMR spectroscopy, the reaction of this phosphole with phenylacetylene gave rise to 2,5-dichloro- and 2,8-dichloro-6-chlorocarbonyl-2-oxo-4-phenylbenzo[e]-1,2-oxaphosphorinines as the major products. The molecular and supramolecular structures of their stable derivatives, viz., 2-tert-butylamino-6-tert-butylaminocarbonyl-5-chloro-2-oxo-4-phenylbenzo[e]-1,2-oxaphosphorinine and isopropylammonium 8-chloro-6-isopropylaminocarbonyl-2-oxo-4-phenylbenzo[e]-1,2-oxaphosphorinin-2-oate, respectively, were established by X-ray diffraction analysis.

The synthesis of N-isocyanurato-substituted aziridino[1,2][60]fullerenes

N-Isocyanurato-substituted aziridino[1,2][60]fullerenes were synthesized for the first time as the main products by the reaction of isocyanurato-substituted azides with C60. The thermal stability and the electrochemical behavior of the compounds synthesized were studied.

Cyclic phosphorochloridites (chloridates) based on chiral butane-2,3-diol and dihydrobenzoin as reagents for the analysis of enantiomeric compositions of alcohols by31P NMR spectroscopy

The use of cyclic phosphorochloridites which were prepared based on PCl3 and chiral butane-2,3-diol or hydrobenzoin as possible reagents for the analysis of the enantiomeric composition of chiral alcohols by31P NMR spectroscopy is considered. The diastereomeric dispersion of chemical shifts of the resulting phosphites as well as of derived phosphates and thiophosphates is compared with that of structurally similar reagents.

REACTIONS OF TETRAPHOSPHORUS DECASULFIDE AND LAWESSON'S REAGENT WITH SILANES CONTAINING A FEW Si-O BONDS

Abstract The reactions of tetraphosphorus decasulfide and Lawessons reagent with tetra-, tri- and dialkoxysilanes were studied. On the basis of these reactions, new S-silyl esters of phosphorus(V) thioacids have been prepared. The prepared compounds were identified by IR, 1H, and 31P NMR and mass spectra as well as elemental analyses.

Reactions of 1,3,2,4-Dithiadiphosphetane-2,4-disulfides with Alkyl Borates

New boron derivatives of dithiophosphonic acids 3a–c and 5 were obtained in the reactions of Lawessons reagent 1a and its homologue 1b with trialkyl borates 2a–c and O-isobutyl diphenylborate 4. Low frequency ultrasound irradiation (22 kHz, power 130 W) leads to reduction in reaction temperature and time in the reactions studied. The prepared compounds were identified by IR, 1H, and 31P NMR and mass spectra as well as elemental analyses.