Systematic Enumeration and Symmetries of Cubane Derivatives

The feasibilities of Fujita's unit‐subduced‐cycle‐index (USCI) approach, Fujita's proligand method, and Fujita's stereoisogram approach have been demonstrated by applying them to cubane derivatives as probes. They provide us with a new set of theoretical foundations for comprehensive investigation of geometric and stereoisomeric features of stereochemistry. The new set of theoretical foundations is based on mathematical formulations so as to explore mathematical stereochemistry as a new interdisciplinary field of stereochemistry.

     

Thermal Transformations of Polyoxadiazoles

Changes of the structural characteristics and electrical properties of fibers based on polyoxadiazole (Arselon) upon a low-temperature thermal treatment in an inert atmosphere were studied. Extremal dependences of the conductivity of the fibers on treatment temperature were observed and a mechanism of this process was suggested. The X-ray diffraction parameters of the Arselon fibers were determined for the extreme states and practical recommendations were made for using a preliminary heating of the fibers.     

Unusual Transformations of Highly Unsaturated Trifluoromethanesulfonamide Derivatives

Russian Journal of Organic Chemistry - Oxidative condensation of N,N-bis(prop-2-yn-1-yl)trifluoromethanesulfonamide in DMSO involved only one ethynyl group, whereas in aqueous methanol...     

Cubane derivatives

An efficient procedure for the preparation of 1,4-bis(hydroxymethyl)cubane by reduction of cubane-1,4-dicarboxylic acid or its dimethyl ester with aluminum hydride was developed. The molecular structure of 1,4-bis(hydroxymethyl)cubane was established by X-ray diffraction analysis. For Part 3, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1387–1390, July, 1998.     

Cubane derivatives

NewN,N′-bis- andN,N,N′, N′-tetrakis-hydroxyalkyl-substituted 1,4-cubanedicarboxamides were synthesized. Nitration of these compounds yielded the corresponding nitrates. The reaction of 1,4-cubanedicarboxylic acid dichloride with ethylene glycol mononitrate and glycerol dinitrate gave ester 1,4-[R¹R²CHOC(O)]₂C₈H₆, where R¹=H and R²=CH₂ONO₂; and R¹=R²=CH₂ONO₂, respectively. The cardiopharmacological activity of some of the synthesized compounds was determined. This allowed us to find for the first time cubane derivatives that exhibit this kind of biological activity. The antiischemic activity of one of these compounds,N,N′-bis(2-nitroxythyl)-1,4-cubanedicarboxdiamide, is higher than that of the well-known Nicorandil. For Part 2, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1169–1172, June, 1998.     

Cubane derivatives

New esters of 1,4-cubanedicarboxylic acid, 1,4-(ROCO)₂C₈H₆ (R=Et (3a), Pr (3b), CMe₃ (3c), C₆H₁₃ (3d), CH₂CF₃ (3e), or CH(CF₃)₂ (3f) were synthesized. The structures of esters3a, 3b, 3e, and3f were established by X-ray diffraction analysis. The cubane framework of compound3b is somewhat distorted, whereas the C−C bond lengths and bond angles in the other compounds remain virtually ideal. For Part 1, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 457–462, March, 1998.     

Cubane derivatives

An efficient procedure was developed for the preparation of 1,4-cubanedicarboxylic acid dihydrazide (1). Its reactions with acetic anhydride, aromatic aldehydes, and acetylacetone were studied.     

Cubane derivatives

Efficient method for the synthesis of cubane-1,4-dicarboxylic and 4-bromocubane-1-carboxylic acid N-(morpholinomethyl)amides has been elaborated. For Part 8, see Ref. 1. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 396–398, February, 2008.     

Synthetic Transformations of the Isoxazolidine Ring of Lappaconitine Derivatives

Chemistry of Natural Compounds -     

Cubane derivatives

New substituted cubane-1,4-dicarboxamides and 4-bromocubanecarboxamides containing the nitroxyl group and amino acid fragments along with the cubane skeleton were synthesized. The cardiac pharmacological activity (both the effect on aorta relaxation and the calcium channel blocking activity) of most of nitroxyalkyl derivatives is equal to or higher than that of N-(2-nitroxyethyl)nicotinamide (nicorandil).     

Cubane derivatives

A precision X-ray structural investigation of 1,4-dimethoxycarbonylcubane at 218 K was carried out. Analysis of the experimental maps of deformational electron density indicates the existence of partial electron density transfer from the cage bonds to the C_cubane-COOR bonds and the shift of the electron density to the symmetrical (relative to the COOMe planes) cube faces.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1210–1213, July, 1993.     

Cubane derivatives

The reduction of 1-bromo-9,9-ethylenedioxypentacyclo[4.3.0.0^2,5.0^3,8.0^4,7]nonane-4-carboxylic acid (2) with lithium aluminum hydride and aluminum hydride in THF was studied. A new effective method for preparing 1-bromo-9,9-ethylenedioxypentacyclo[4.3.0.0^2,5.0^3,8.0^4,7]-non-4-ylcarbinol (1) based on reduction of2 with AlH₃ under mild conditions was developed.     

Porphyrin Derivatives of Macrocyclic Tetraindoles: Synthesis and Chemical Transformations

Polyphenols chemically bonded to a molecular platform based on macrocyclic tetraindole porphyrin derivatives were synthesized for the first time. The tetraindole was prepared by two-step tetramerization of 3-(4′-bromophenyl)-4,6-dimetoxyindole. Polyphenols of this type were obtained by the Suzuki–Miyaura reaction between bromo-containing cyclic tetraindole and monoboryl-substituted porphyrin. The subsequent transformations of this molecular construction gave rise to epoxidized polyphenol on a tetraindole support, which served for the development of a new negative resist for electron-beam nanolithography. The resist can form patterns with a 12 nm resolution.     

Kinetics of Thermal Transformations of Precipitated Magnetite and Goethite

The aim of the present study was to determine the kinetic equations for the thermal transformations of precipitated iron oxides and hydroxides, namely for the process of thermal dehydroxylation of goethite and consecutive of hematite crystal structure growth as well as for the oxidation of magnetite to maghemite and its thermal transformation into crystalline hematite. The investigations have been carried out using thermogravimetry (TG/DTG/DTA), X-ray powder diffractometry (XRD) and high temperature powder diffractometry (HT-XRD). This presentation contains the continuation of our earlier works. This revised version was published online in July 2006 with corrections to the Cover Date.     

Nucleophilic Transformations of Heterocyclic Derivatives of 4-Heteryl-2,4-dioxobutanoic Acids

Proceeding from 4-heteryl-2,4-dioxobutanoic acids were prepared (Z)-3-heteroylmethylene-1,2,3,4-tetrahydro-2-quinoxalones that when treated with oxalyl chloride afforded 3-heteroyl-1,2,4,5-tetrahydropyrrolo[1,2-a]quinoxaline-1,2,4-triones. The latter took in reactions with o-aminophenol and o-phenylenediamine two different directions.     

Thermal Transformations in Systems Based on Natural Apatites

Abstract

The mechanisms of thermal transformations in different types of natural phosphates and their mixtures with H₃PO₄ and Na₂CO₃ are discussed.     

Thermal and Photofragmentation of N-Benzoylhydrazone Derivatives

Two selected benzoylhydrazones I and II were subjected to thermolysis by reflux at 200 °C. Benzil, benzoic acid, biphenyl, benzanilide together with the corresponding ketones, nitriles and imines were isolated. Similar treatment of the third hydrazone III at 250 °C afforded, in addition to the previous products, bibenzyl, stilbene, and 2-phenylindole. Photolysis of the same hydrazones I-III in acetonitrile gave the previously reported products but in different ratios along with azine derivatives and substituted methanes. A free radical mechanism involving homolysis of the N-N and C-N bonds is suggested, substantiated by trapping of phenyl radical with isoquinoline, to account for the formation of the identified products.     

Synthesis,Structure, and Transformations of New Endic Anhydride Derivatives

4-Azatricyclo[5.2.1.02,6]dec-8-ene and its N-phenyl derivative were synthesized by reaction of endic anhydride with amines, transformation of the amido acids thus obtained to imides, and subsequent reduction of the latter with lithium aluminum hydride. The unsubstituted tricyclic amine was brought into reactions with electrophilic reagents: p-toluenesulfonyl chloride, p-toluoyl chloride, m-tolyl isocyanate, phenyl isothiocyanate, and endic anhydride to obtain a number of new derivatives; also, the corresponding salt with 1-adamantanecarboxylic acid was isolated. N-(p-Tolylsulfonyl)- and N-(m-tolylcarbamoyl)-4-azatricyclo-[5.2.1.02,6]dec-8-enes were oxidized to the corresponding 8,9-epoxy derivatives with monoperoxyphthalic acid. The structure of the products was confirmed by the data of IR, ¹H and ¹³C NMR, and mass spectra. The molecular structures of N-(p-iodophenyl)bicyclo[2.2.1]hept-2-ene-endo-5,endo-6-dicarboximide and N-phenyl-4-azatricyclo[5.2.1.02,6]dec-8-ene were established by X-ray analysis.