Pyridinium salts

New 4- (benzazol-2-yl)pyridinium salts have been synthesized. Their reduction in a neutral medium with sodium tetrahydroborate has given 2-(1,2,5,6-tetrahydropyridin-4-yl)benzazoles. The catalytic hydrogenation of the latter leads to piperidine derivatives which have also been synthesized by an independent route.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 104–107, January, 1974.     

The synthesis of spirane and bicyclic thiolanes from homoallylic thiols

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2155–2156, September, 1989.     

Synthesis of 2-substituted methylenecycloalkanes from 1-(dialkyl-borylmethyl)cycloalkenes

Conclusions We have developed a novel general method for the preparation of 2-substituted methylenecycloalkanes, which is based upon the allylboration of carbonyl compounds and alkoxyacetylenes by means of hitherto unknown cycloalkenylmethyl(dialkyl)boranes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, PP. 420–425, February, 1988.     

Reaction of dialkylboric anhydrides with 2-amino- and 2-hydroxypyridine

Conclusions The anhydrides of dialkylboric acids react with 2-aminopyridine at 150–190° and with 2-hydroxypyridine at 100–170° to give cyclic coordination compounds of boron and saturated hydrocarbons.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1919–1921, August, 1977.     

Use of actinides in uncommon oxidation states for their extraction and separation from alkaline solutions

The extraction behavior of Am(IV–VI) from high pH solutions in the presence of carbonates, pyrophosphates or polyphosphates of alkali metals and of Np(VI–VII) from alkaline solutions with acylpyrazolones (1-phenyl-3-methyl-4-benzoylpyrazolone-5, PMBP) and extractants of the phenol type [bis(2-oxy-4-alkyl-benzoil)amin, CAAF] has been studied. The extraction ability of phenolic extractants with respects to Np(VII) is determined generally by its state in the alkaline solution. Maximum extraction is observed when Np(VII) is present as hydroxo complex and minimum extraction, when the solution contains oxo-ions. During the extraction the reduction of Np(VII) to Np(VI) is possible. Hexavalent neptunium can be extracted by phenol extractants too, but more slowly and with smaller distribution coefficients in comparison with Np(VII). The stabilization of transplutonium elements (TPE) in the highest oxidation states in alkaline solutions contaning carbonate and pyrophosphate ions, in combination with extraction by PMBP and CAAF, allows to realize the separation of transplutonium elements which are very similar in their properties. Methods of separation for americium and curium have been developed. They are based on the ability of trivalent curium to be extracted quantitatively from 0.1M sodium pyrophosphate solution (pH 10) and 1.0M potassium carbonate solution (ph 13.4) by PMBP in chloroform and by CAAF in carbon tetrachloride, respectively, with high distribution coefficients, whereas americium which is electrochemically oxidized to Am(VI) in these media, remains in the aqueous phase, since it reduces only to Am(V) when contacting the extractant. The separation factor of the couple Cm(III) Am(VI) is about 10³.     

Chemical peculiarities and structure of 2-(indane-1′, 3′-dionid-2′-yl)pyridinium (α-pyrophthalone)

The fine structure of 2-(indane-1,3-dionid-2-yl)pyridinium (-pyrophthalone) was determined by PMR spectroscopy and x-ray diffraction analysis. The -pyrophthalone molecule is almost planar; the dihedral angle between the pyridine ring and the indanedione ring is 5°. The structure is stabilized by an intramolecular hydrogen bond with a length of 2.73 Å. The molecules are packed in the crystal at van der Waals distances similar to those in molecular self-complexes. The data obtained for -pyrophthalone confirm a dipolar ion structure.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1076–1080, August, 1978.