The oxidation of 1,2-C 2 B 10 H 12 (1) with 100% nitric acid was studied in two solvents (CH 2 C1 2 and CCl 4 ). Under the action of superacid (CF3SO3H), the compound 9-HO-1,2-C 2 B 10 H 11 (2) gives the onium cation 9-H 2 O + -1,2-C 2 B 10 H 11 involved in the salt [9-H 2 O + -1,2-C 2 B 10 H n ]-CF 3 SO 3 − , as demonstrated by u B NMR spectroscopy. The experimental and simulated u B NMR spectra of the cation 9-H 2 O + -1,2-C 2 B 10 H 11 are in satisfactory agreement with each other. In the presence of a base, compound 2 is transferred from an ethereal solution to an aqueous alkaline solution giving the anion 9-O − - 1,2-C 2 B 10 H 11 . The structure of compound 2 was confirmed by 1 H, 11 B, 11 B 1 H, 11 B- 11 B COSY NMR spectroscopy, IR spectroscopy, and gas chromatography mass spectrometry and was additionally established by X-ray diffraction.

Взаимодействием смешанного ангидрида, синтезированного из третбутилоксикарбонилпролиллейцина и изо-бутилхлорформиата и вводимого в дальнейшие превращения без выделения в индивидуальном виде, с гидрохлоридом глицинамида в среде ДМФ:CH2Cl2 получен трет-бутилоксикарбонилпролиллейцилглицинамид 1. Удалением трет-бутилоксикарбонильной аминозащитной группы действием раствора хлористого водорода в диоксане или муравьиной кислотой на 1 получены гидрохлорид 2 и формиат 3 пролиллейцилглицинамида. Обработка соединения 2 эквимолярным количеством этилата натрия, а соединения 3 водным раствором аммиака давала пролиллейцилглицинамид 4.

Prolylproline has been synthesized by both classical peptide synthesis method utilizing tert -butoxycarbonyl or trifluoroacetyl protection of the NH group and carbodiimide-promoted peptide bond formation and by opening of the dioxopiperazine ring in octahydrodipyrrolo[1,2- a :1′,2′- d ]pyrazine-5,10-dione obtained by thermolysis of proline methyl ester.

Deboration of 1-PhCH 2 -1,2-C 2 B 10 H 11 by heating in ethanolic potassium hydroxide afforded Me 4 N + [7-PhCH 2 -7,8-C 2 B 9 H 11 ] − which was treated with excess halosuccinimide (NCS, NBS) in acetonitrile or with elemental iodine or bromine in methanol to obtain Me 4 N + [7-PhCH 2 -9,11-X 2 -7,8-C 2 B 9 H 9 ] − (X = Cl, Br, I). The reaction of 1-PhCH 2 -1,2-C 2 B 10 H 11 with an equimolar amount of iodine gave a mixture of Me 4 N + ·[7-PhCH 2 -11-I-7,8-C 2 B 9 H 10 ] - and Me 4 N + [7-C 6 H 5 CH 2 -9-I-7,8-C 2 B 9 H 10 ] − at a ratio 1:1.8 due to steric effect of the benzyl substituent. The 11 B chemical shifts of each μ-H tautomer of Me 4 N + [7-PhCH 2 -9,11-X 2 -7,8-C 2 B 9 H 9 ] − (X = H, F, Cl, Br, I) were calculated at the DFT level of theory, and their contributions to the average 11 B NMR spectrum and the corresponding tautomeric equilibrium constants were determined.

New preparative procedures were developed applying tert-butoxycarbonyl or trifluoroacetyl protection of amino groups in the synthesis of L-leucyl-L-isoleucine and L-isoleucyl-L-leucine.

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Conditions were developed for simultaneous preparation of N å -trifluoroacetyl-L-lysine and N α , N å -bis(trifluoroacetyl)-L-lysine at overall conversion of initial lysine monohydrochloride up to 82%. By reaction of dimethyl L-glutamate with N α , N å -bis(trifluoroacetyl)-L-lysyl chloride in the presence of triethylamine or with N α -carboxyanhydride of N å -trifluoroacetyl-L-lysine with subsequent removing protecting groups in the formed dipeptides by treating with water-ethanol solution of sodium hydroxide we obtained L-lysyl-L-glutamic acid. Physicochemical characteristics of samples obtained coincided with characteristics of L-lysyl-L-glutamic acid described in the literature thus suggesting that no racemization occurred either at the stage of peptide bond formation or at deprotection.

New chiral pincer ligands having CH=N moieties were synthesized by condensation of 1 H -pyrrole-2,5-dicarbaldehyde with l -methionine and l -histidine methyl esters. Their reduction under mild conditions (NaBH 4 , −30°C) gave the corresponding amine ligands in high yields. An improved procedure for the preparation of 1 H -pyrrole-2,5-dicarbaldehyde was proposed.

Conditions have been developed for the synthesis of N-trifluoroacetyl-β-alanine, N-tifluoroacetyl-β-alanyl chloride, and N-trifluoroacetyl-β-alanine 4-nitrophenyl ester. These compounds reacted with histidine methyl ester or sodium salt to give N-trifluoroacetyl-β-alanyl-l-histidine methyl ester CF3CONHCH2CH2·CONHCH(CH2C3H3N2)COOCH3 and N-trifluoroacetyl-β-alanyl-l-histidine CF3CONHCH2CH2CONHCH·(CH2C3H3N2)COOH. Their hydrolysis with a solution of sodium hydroxide in aqueous ethanol, followed by acidification with trifluoroacetic acid, led to the formation of β-alanyl-l-histidine (l-carnosine).

The dipyridyl complexes of the copper salts of bis-o-dicarbollyliron(III), -cobalt(III), and -nickel(III) are investigated by means of EPR spectroscopy. Theoretical models of the EPR spectra of copper(II) ions in these complexes are constructed and their spectral parameters are determined. It is shown that in all cases the tetragonally distorted octahedron is the most probable coordination sphere of the Cu2+ ions.

The complex salts [( o -C2B9H11)2M 3+ ] 2 M' 2+ ·4bipy, where M = Fe, Co, or Ni, M' = Fe, Co, Ni, Cu, Mn (M ≠ M'), and bipy is 2,2'-bipyridyl, were synthesized. The salts with M = Ni decompose to give 3-(2,2'-bipyridyl)-3,1,2-nickelacarborane, when refluxed in alcohol, and to give 2-(2,2'-bipyridyl)-2,1,7-nickel acarborane, when refluxed in dodecane (216°C).

The reaction of bis( o -dicarbollyl)nickel(iv) with PPh 3 in EtOH gave rise to the complex 3,3-(PPh 3 ) 2 -3,1,2-NiC 2 B 9 H 11 ( 2 ) whose structure was established by X-ray diffraction analysis.

Co-electrolysis of potassium 1,2-dicarbadodecahydroundecaborate and indene in 0.1 N sodium bromide solution in dimethylsulfoxide using iron electrodes afforded pi-indenyl-pi-(3)-1,2-dicarbollyliron(III).