Synthesis of organoaluminum compounds containing a silicon atom in the alkyl chain

Summary In the reactions of diisobutylaluminum hydride with allyltrimethylsilane and with trimethylvinylsilane, tris[3-(trimethylsilyl)propyl]aluminum and tris[2-(trimethylsilyl)ethyl]aluminum, respectively, were formed.     

Heterocyclic compounds with a bridgehead nitrogen atom. Synthesis in the imidazo[1,2-c]quinazoline series

The structures of imidazo[1,2-c]quinazolines were reexaminated and established by spectroscopic studies with the aid of high-field ¹H and ¹³ C nmr and mass spectra. In acidic media, 3 reacts to give the products of electrophilic substitution reaction and ring opening compound 5 , leading to the imidazo[1,2-c]benzo[e]-[1,2,3]triazine ring.     

Siloxazolidines with a pentacovalent silicon atom (review)

The literature data and the results of the authors' research on heterocyclic systems containing a pentacovalent silicon atom in a siloxazolidine ring are examined. Particular attention is directed to silatranes — stable organic derivatives of pentacovalent silicon that have high physiological activity.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1299–1310, October, 1977.     

Mesoionic compounds with a bridged nitrogen atom.

The cyclization of (4-quinazolinylthio)phenylacetic and acetic acids gives extremely reactive thiazolo[3,2-c]quinazolinium 3-oxides, which, depending on the structure of the mesoionic ring, react with either electrophilic or nucleophilic reagents.See [1] for Communication 16.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 408–412, March, 1989.     

Indolopyridines with a bridging heteroatom

Reaction of 2-acetylpyridine with 4-[2.2]paracyclophanyllithium or 4-acetyl[2.2]paracyclophane with 2-pyridllithium gives 1-([2.2]paracyclophan-4-yl)-1-(2-pyridyl)ethanol. Its molecular and crystalline structures have been studied by x-ray analysis. It was found that heating this alcohol in acid medium causes dehydration and heterocyclization to give 1-paracyclophanyl-1-pyridylethylene and 10-methyl[2.2]paracyclophano[4,5-bindolizine.For communication 9 see [1]. This report is also communication [5] in the series Synthesis, Structure, and Biological Activity of [2.2]Paracyclophanes (for communication 4 see [2]).Russian University of National Friendship, Moscow 117198. A. N. Nesmeyanov Institute of Organoelemental Compounds, Russian Academy of Sciences, Moscow 117813. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 793–800, June, 1997.     

Molecular and chemical dynamics of a biradical with six-coordinate silicon atom

The intramolecular dynamics of a silicon biradical complex witho-semiquinone ligands was studied in a frozen toluene solution. Analysis of the broadening and shifts of the canonical components in the ESR spectrum of this biradical allows one to detect the abrupt reorientation of the magnetic axes due to intramolecular single bond-unpaired electron exchange. The frequencies of chemical exchange at low temperatures were estimated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1726–1730, October, 1993.     

Octaorganylsilasesquioxanes with chloromethyl substituents at the silicon atom

The combined heterofunctional hydrolytic polycondensation of organyltriethoxysilanes with chloromethyltrichlorosilane gives chloromethyl derivatives of octaorganylsilasesquioxanes, (ClCH₂)_n(R)_8–n[SiO_1.5]₈, where R=CH₃, C₂H₃, and C₂H₅. The dissociative ionization of these products occurs through a pathway different from that for the fragmentation of R- T₈ with hydrocarbon substituants at the silicon atom.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 441–445, February, 1990.     

Synthesis and structures of heterasumanenes having different heteroatom functionalities

After the protection of two α-carbons of the dibenzothiophene moiety in triphenylenothiophene 1 by trimethylsilyl groups, the resulting compound 4 reacted with butyllithium followed by dichlorodimethylsilane to afford 10H-silolo[2′,3′,4′,5′:4,5]triphenyleno[1,12-bcd]thiophene 8, which reacted with butyllithium followed by dichlorodimethylsilane to afford novel heterasumanene 11. Using dichlorodimethylstannane instead of dichlorodimethylsilane afforded heterasumanene 12, which is the first example of a heterasumanene having three different heteroatom functionalities.     

Synthesis of methylcyclotetra(hexa)siloxanes with different reactive groups at the same silicon atom

Representatives of methylcyclotetra(hexa)siloxanes with two different reactive groups at the same silicon atom (CH₂=CH and Cl, H and Cl, CH₂=CH and OH) were synthesized for the first time by condensation of trichlorovinylsilane with dihydroxydimethylsilane, and by stepwise condensation of trichloro-and trichlorovinylsilane with 1,3-dihydroxy-1,1,3,3-tetramethyldisiloxane in the presence of amines (aniline, pyridine, and triethylamine). The condensation with 1,3-dihydroxy-1,1,3,3-tetramethyldisiloxane with a large excess of trichlorosilane, unlike the condensation with trichlorovinylsilane, occured intramolecularly to give monochlorotetramethylcyclotrisiloxane in a high yield and intermolecularly to give 1,1,7,7-tetrachloro-3,3,5,5-tetramethyl-1,7-dihydrotetrasiloxane. The structures of the synthesized compounds were confirmed by ¹H and ²⁹Si NMR spectroscopy, IR spectroscopy, and mass spectrometry. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 932–936, June, 2006.     

Heterocyclic nitrogen compounds in whisky and beer

Summary Differences in the composition of the heterocyclic nitrogen compounds in whisky and beer were studied using capillary gas chromatography. The raw materials common to both whisky and beer lead to similar N-heterocycles being detected in both beverages. Pyridines, pyrazines, and thiazoles could be identified in both beverages. In addition, pyrroles were detected in beer and quinolines in whisky. Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984     

Mesoionic compounds with a bridged nitrogen atom. 13. Thiazolopyrimidoindoles

Derivatives of a new heterocyclic system, viz., thiazolo[3,43,2]pyrimido-[4,5-b]indole, are formed when 4-amino-2-methylthio-5-phenylthiazolium benzenesulfonate is heated with 3-formyloxindole in phosphorus oxychloride.See [1] for communication 12.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 502–504, April, 1985.     

Synthesis of compounds with a four-coordinate boron atom from 2-aminobenzazoles and nitriles

The reactions of 2-aminobenzazoles with nitriles in the presense of organoboranes results in the formation of novel tricyclic chelate boron compounds with N-(benzazol-2-yl)amidines as ligands, N-(Benzothiazol-2-yl)-p-chlorobenzamidine was prepared from 2-aminobenzothiazole and p-chlorobenzonitrile via the corresponding chelate.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 1019–1021, April,.