1H and 13C NMR spectra,isomers, and imine-enamine tautomers of N-(1,2,5-trimethyl-4-piperidylidene)aniline

The product of condensing 1,2,5-trimethylpiperidin-4-one with aniline has been investigated by NMR spectroscopy. Three isomers of N-(1,2,5-trimethyl-4-piperidylidene)aniline have been identified differing in the configuration of the methyl groups at C₂ and C₅ of the piperidine ring and the Z,E isomerism about the C=N bond. Traces of the enamine tautomeric form of the imine were also detected. , , and spin-spin couplings were used to determine the structural configuration of the isomers.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1405–1408, October, 1989.     

Magnesium Hexafluoridozirconates MgZrF6·5H2O,MgZrF6·2H2O,and MgZrF6: Structures,Phase Transitions,and Internal Mobility of Water Molecules

The MgZrF₆ · n H₂O (n = 5, 2 and 0) compounds were studied by the methods of X‐ray diffraction and ¹⁹F, MAS ¹⁹F, and ¹H NMR spectroscopy. At room temperature, the compound MgZrF₆ · 5H₂O has a monoclinic C‐centered unit cell and is composed of isolated chains of edge‐sharing ZrF₈ dodecahedra reinforced with MgF₂(H₂O)₄ octahedra and uncoordinated H₂O molecules and characterized by a disordered system of hydrogen bonds. In the temperature range 259 to 255 K, a reversible monoclinic ? two‐domain triclinic phase transition is observed. The phase transition is accompanied with ordering of hydrogen atoms positions and the system of hydrogen bonds. The structure of MgZrF₆ · 2H₂O comprises a three‐dimensional framework consisting of chains of edge‐sharing ZrF₈ dodecahedra linked to each other through MgF₄(H₂O)₂ octahedra. The compound MgZrF₆ belongs to the NaSbF₆ type and is built from regular ZrF₆ and MgF₆ octahedra linked into a three‐dimensional framework through linear Zr–F–Mg bridges. The peaks in ¹⁹F MAS spectra were attributed to the fluorine structural positions. The motions of structural water molecules were studied by variable‐temperature ¹H NMR spectroscopy.     

Synthesis and studies of magnesium hexafluorozirconates MgZrF<Subscript>6</Subscript> · <Emphasis Type="Italic">n</Emphasis>H<Subscript>2</Subscript>O (<Emphasis Type="Italic">n</Emphasis> = 5, 2, 0)

Crystalline magnesium hexafluorozirconate MgZrF₆ · 5H₂O isostructural to MnZrF₆ · 5H₂O, and having a chain-like structure, was synthesized and studied. According to thermogravimetry, the compound undergoes stepwise dehydration in the temperature range of 50–420°C to give the stable phase MgZrF₆ · 2H₂O and the final product MgZrF₆ isostructural to the cubic modification of MZrF₆ (M = Cu, Fe). The vibrational spectra of the initial compound and the dehydration products are analyzed and the structures of the compounds are considered.     

Condensation of N-(piperidylidene-4)arylamines with acetylenedicarboxylic esters

The substituted piperidines, N-(piperidin-3-en-4-yl)-N-(1,2-dimethoxycarbonyl-etheno)arylamine and 1-aryl-3,4,5,6-tetramethoxycarbonyl-1,2-dihydrospiro[cyclo-[pyridine-2,4-piperidine], were synthesized by the condensation of acetylenedicarboxylic ester with an azomethine, obtained from a -piperidone. It was found that the amounts of 11 and 12 addition compounds obtained depends on the ratio of starting reagents. Compounds isomeric at the vinyl group were examined in the case of one of the 11 addition compounds. N-(1,2,5-trimethylpiperidin-4-yl)-N-(1,2-dimethoxycarbonyletheno)aniline was prepared by two methods.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 943–946, July, 1986.     

Di- and trimethyl-substituted 2-azafluorenes and dibasic acids of 2-azafluorenone

Dehydrocyclization of the corresponding 2,5-dimethyl-4-arylpyridines gave 3,5- and 3,8-dimethyl- and 3,5,7- and 3,5,8-trimethyl-2-azafluorenones. Dibasic acids of 2-azafluorenone were obtained from -carboxyarylcinchomeronic acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1664–1667, December, 1972.     

The Composition of Intermediate Products of the Thermal Decomposition of (NH<Subscript>4</Subscript>)<Subscript>2</Subscript>ZrF<Subscript>6</Subscript> to ZrO<Subscript>2</Subscript> from Vibrational-Spectroscopy Data

Thermal decomposition of (NH₄)₂ZrF₆ resulting in ZrO₂ formation within the temperature range of 20°–750°С has been investigated by means of thermal and X-ray diffraction analysis and IR and Raman spectroscopy. It has been established that thermolysis proceeds in six stages. The vibrational-spectroscopy data for the intermediate products of thermal decomposition have been obtained, systematized, and summarized.     

Benzo[f]-3-aza- and -10-azafluoroanthenes

Reduction of 3-methyl-9-(o-tolyl)-2-azafluoren-9-ol (I) with tin in hydrochloric acid gave 3-methyl-9-(o-tolyl)-2-azafluorene, dehydrocyclization of which on a K-16 catalyst at 520–500°C gave a complex mixture, from which four substances — 2-methylbenzo[f]-3-azafluoranthene, 11-methylbenzo[f]-10-azafluoranthene, benzo[f]-3-azafluoroanthene (II), and I-were isolated and identified by means of the IR, UV, and PMR, and mass spectra. It is shown that the dehydrocyclization proceeds through the hydrogen atoms of the methyl group of the tolyl substituent and takes place at the 8-C or 1-C atom of the azafluorene system. The formation of products II and I constitutes evidence that the reaction is accompanied by partial demethylation or oxidation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1245–1247, September, 1977.     

Preparation of spiroaziridinefluorene,spiroindoxyl-fluorene,and Β-aminopropionic acid ester with a 4-azafluorene fragment

It has been established that the reaction of 9-(p-methoxyphenylimino)fluorene with dichlorocarbene (conditions of phase-transfer catalysis) proceeds in two directions — the formation of spiroaziridinefluorene and of spiroindoxylfluorene, the structure of which has been demonstrated. Opening of the aziridine ring of spiroaziridinefluorene has been accomplished. From the analagous azamethine, 4-aza-fluorene, an ester of N-substituted -aminopropionic acid with a 4-azafluorene fragment was obtained by alkylation of its dianion with methyl chloroacetate.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 895–897, July, 1986.