The formation of tetracyclo[7.2.1.02,5.02,8]dodeca-6,10-dienes under conditions of thermal isomerization of spiro[2.4]hepta-4,6-diene into bicyclo[3.2.0]hepta-1,3-diene

The formation of the novel hydrocarbons, tetracyclo[7.2.1.0^2,5.0^2,8]dodecadienes, as a result of thermal isomerization of spiro[2.4]hepta-4,6-diene into bicyclo[3.2.0]hepta-1,3-diene and its capture by 1,3-dienes is demonstrated. The conditions of thermal isomerization and dimerization of the spiroheptadiene are studied. Cyclopropanation of the polycyclic dienes formed by diazomethane in the presence of Pd-catalysts was accomplished, and occured solely through the norbornene double bond.For preliminary communication see ref.¹ Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 132–137, January, 1993.     

Stereoselective Insertion of Benzynes into Lawsones: Synthesis of Biologically Important Benzannulated Bicyclo[3.3.0]octanes

An ideal stereoselective insertion of in situ generated benzynes into lawsones through domino formal [2+2]-cycloaddition followed by rearrangement is disclosed. The reaction allowed for the preparation of biologically important benzannulated bicyclo[3.3.0]octanes in good yields and with excellent selectivities by using simple substrates and conditions.     

13C NMR spectra of polycyclic compounds. Bicyclo[2.2.1]heptadiene tetramers

Comparison of experimental and calculated chemical shifts of carbon atoms in¹³C NMR spectra of two isomeric dodecacyclo[14.9.1.1^4,13.1^7,10.0^2,15.0^3,14.0^5,12.0^6,11.0^17,25.0^18,24.0^19,21. 0^20,24]-octacos-8-enes, bicyclo[2.2.1]heptadiene tetramers, confirmed theirexo-trans-exo-trans-exo-endo-andexo-trans-exo-trans-exo-exo-configurations. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2545–2547, December, 1998.     

An efficient synthesis of pentacyclo[4.2.0.02,5.03,8.04,7]octane-1,4-dicarboxylates

Dialkyl pentacyclo[4.2.0.0^2,5.0^3,8.0^4,7]octane-1,4-dicarboxylates (where alkyl is methyl,iso-propyl, 2-fluoro-2,2-dinitroethyl, or 2,2,2-trinitroethyl) were prepared in high yields by O-alkylation of 1,4-cubanedicarboxylic acid with the corresponding monoalkyl sulfates.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 801–802, April, 1993.     

Development of Bicyclo[3.1.0]hexane-Based A3 Receptor Ligands: Closing the Gaps in the Structure–Affinity Relationships

The adenosine A₃ receptor is a promising target for treating and diagnosing inflammation and cancer. In this paper, a series of bicyclo[3.1.0]hexane-based nucleosides was synthesized and evaluated for their P1 receptor affinities in radioligand binding studies. The study focused on modifications at 1-, 2-, and 6-positions of the purine ring and variations of the 5′-position at the bicyclo[3.1.0]hexane moiety, closing existing gaps in the structure–affinity relationships. The most potent derivative 30 displayed moderate A₃AR affinity (Ki of 0.38 μM) and high A₃R selectivity. A subset of compounds varied at 5′-position was further evaluated in functional P2Y₁R assays, displaying no off-target activity.     

Thionation of the monoacetal of pentacyclo[5.4.0.0.0.0]undecane-8,11-dione

As part of a programme to synthesize thione derivatives with pentacyclo[5.4.0.0^2,6.0^3,10.0^5,9]undecane moieties it was decided to sulfurize the monoacetal 6 of pentacyclo[5.4.0.0^2,6.0^3,10.0^5,9]undecane-8,11-dione 2. Unexpectedly the diol 9 was isolated as the product.     

Synthesis and evaluation of multitopic bisbenzothiazolyl calix[4]arenes for ionic toxicants

Abstract

Two new benzothiazolyl calix[4]arene-based multitopic molecular receptors L-1 and L-2 have been synthesised and evaluated for recognition of ionic toxicants. The receptors selectively interact with copper, silver and fluoride ion toxicants as assessed through UV-visible, NMR and colorimetric techniques. The stability of L-1:Cu⁺² and L-2:Cu⁺² complexes was found to be higher than that of complexes formed with Ag⁺ and F^– complexes in the presence of trifluoroacetic acid. Superiority of L-1 over L-2 for analysis of identified toxicants has been determined by measurement of binding constants.     

The dimerization and photochemical rearrangement of pentacyclo-[5.4.0.0.0.0]undecane-8-thione

Pentacyclo[5.4.0.0^2,6.0^3,10.0^5,9]undecan-8-one 1 is readily sulfurated into pentacyclo[5.4.0.0^2,6.0^3,10.0^5,9]undecane-8-thione 2 with Lawesson’s reagent in dry THF. Upon standing at ambient temperature the thione 2 formed the corresponding thio-dimer 3 within 10 days. When the thio-dimer 3 was exposed to oxygen and ultraviolet light an unexpected photochemical oxidation and rearrangement took place to form the stable disulfenate 5.     

Molecular and crystal structure of 23,24,25,26,27,29,30-heptamethyl-19,28-oxahexacyclo[15.13.18.017,18.013,14.08,9.05,10]tetracos-3-yl acetate

The molecular structure of 23,24,25,26,27,29,30-heptamethyl-19,28-oxahexacyclo[15.13.18.0^17,18.0^13,14.0^8,9.0^5,10]tetracos-3-yl acetate III. Compound III C₃₂H₅₂O₃ crystallizes in the monoclinic crystal system with the unit cell parameters a = 13.265(15) ?, b = 6.481(7) ?, c = 32.274(4) ?, β = 99.333(2)°, space group C2, Z = 4, d = 1.176 g/cm³. Original Russian Text Copyright ? 2009 by N. I. Medvedeva, O. B. Flechter, and A. A. Korlyukov __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 2, pp. 399–401, March–April, 2009.     

Rh(I)-catalyzed allenic Pauson-Khand reaction: first construction of the bicyclo[6.3.0]undecadienone ring system

The Rh(I)-catalyzed Pauson-Khand reaction of allenynes afforded the bicyclo[6.3.0]undecadienones as well as their benzo and furo derivatives. In addition, a novel [RhCl(CO)₂]₂-catalyzed [2,3]-sigmatropic rearrangement of the sulfinic ester species of propargyl alcohols was developed.     

五元瓜环与钕离子在四氯酸锌离子诱导下构筑的配合超分子自组装

在四氯酸锌离子诱导下,五元瓜环能与钕离子构筑形成二维配合超分子自组装。在HCl介质中,Zn²⁺容易形成四氯酸锌离子,在其诱导作用下,钕离子和五元瓜环端口羰基氧直接配位形成二维超分子自组装体。结果表明锌离子作为一种结构导向剂在形成瓜环基超分子自组装体中起到重要作用。     

五元瓜环与钕离子在四氯酸锌离子诱导下构筑的配合超分子自组装

在四氯酸锌离子诱导下,五元瓜环能与钕离子构筑形成二维配合超分子自组装。在HCl介质中,Zn2+容易形成四氯酸锌离子,在其诱导作用下,钕离子和五元瓜环端口羰基氧直接配位形成二维超分子自组装体。结果表明锌离子作为一种结构导向剂在形成瓜环基超分子自组装体中起到重要作用。     

Structure of methyl-7-methoxy-7-phenyl-6-<Emphasis Type="Italic">endo</Emphasis>-halobicyclo[3.1.1]heptane-6-<Emphasis Type="Italic">exo</Emphasis>-carboxylate diastereomers in single crystals

The structure of diastereomeric methyl-7-anti-methoxy-7-syn-phenyl-and methyl-7-syn-methoxy-7-anti-phenyl-6-endo-bromobicyclo[3.1.1]heptane-6-exo-carboxylates 2a and 3a and their chlorine-and iodine-substituted analogs 2b and 3c was studied by XRD. The diastereomers differ in the geometrical parameters of the carbon framework of the molecules. The C(1)-C(2)-C(3)-C(4)-C(5)-C(6) six-membered ring is in the intermediate conformation between envelope and chair in structures 2 and envelope in structures 3. In compound 2a, the cyclobutane fragment has a higher degree of folding than in 3a; one of the possible reasons for that is the donor-acceptor interaction between the 6-methoxycarboxylic and 7-methoxy groups in molecule 2a.     

Regioselective synthesis of pyrano[3,2-c]pyrimidine derivatives via a palladium-catalyzed unusual [1,3] aryloxy shift and cycloisomerization: first report of a [1,3] shift of an aryloxy group

Uracil-annulated pyrano heterocycles are regioselectively synthesized in excellent yields (92-100%) via a palladium-catalyzed unusual [1,3] aryloxy shift followed by 6-endo dig cyclization and [1,3] prototropic shift.     

Solid substrate-room temperature phosphorimetry for the determination of trace protein using ion association complex [Cu(BPY)2]·[(Fin)2] as a phosphorescent probe

Fluorescein (HFin) emitted strong and stable room temperature phosphorescence (RTP) on filter paper after set at 50 °C for 10 min using Li⁺ as the ion perturber. HFin existed as Fin⁻ when the pH value was in the range of 5.45–7.36. Fin⁻ could react with [Cu(BPY)₂]²⁺ (BPY: α,α-bipyridyl) to produce ion association complex [Cu(BPY)₂]²⁺·[(Fin)₂]²⁻, which could enhance the RTP signal of Hfin. In the presence of bovine serum albumin (BSA), the –COOH group of Fin⁻ in the [Cu(BPY)₂]²⁺·[(Fin)₂]²⁻ could react with the –NH₂ group of BSA to form the ion association complex [Cu(BPY)₂]²⁺·[(Fin-BSA)₂]²⁻, which contained –CO–NH– bond. This complex could sharply enhance the RTP signal of Hfin and the ΔI_p was directly proportional to the content of BSA. According to the facts above, a new solid substrate-room temperature phosphorimetry (SS-RTP) for the determination of trace protein had been established using the ion association complex [Cu(BPY)₂]²⁺·[(Fin)₂]²⁻as a phosphorescent probe. This method had wide linear range (0.40 × 10⁻⁹–280 × 10⁻⁹ mg l⁻¹), high sensitivity (the detection limit (LD) was 1.4 × 10⁻¹⁰ mg l⁻¹), good precision (RSD: 3.4–4.9%) and high selectivity (the allowed concentration of coexistent ions or coexistent materials was high). It had been applied to the determination of the content of protein in 10 kinds of real samples, and the result agreed well with pyrocatechol violet-Mo (VI) method (P.V.M.M.), which indicated it had high accuracy. Meanwhile, reaction mechanism for the determination of trace protein with [Cu(BPY)₂]²⁺·[(Fin)₂]²⁻ phosphorescent probe was also discussed. The academic thought of this research could not only be used to develop many kinds of ion association complex phosphorescent probes, but also provided a new way to promote the sensitivity of SS-RTP.     

Coordination behaviour of the multidentate Schiff base 2,6-bis(2-hydroxyphenyliminomethyl)pyridine towards the fac-[Re(CO)3] and [ReO] cores

The seven-coordinate rhenium(III) complex cation [Re^III(dhp)(PPh₃)₂]⁺ was isolated as the iodide salt from the reaction of cis-[Re^vO₂I(PPh₃)₂] with 2,6-bis(2-hydroxyphenyliminomethyl)pyridine (H₂dhp) in ethanol. In the complex fac-[Re(CO)₃(H₂dhp)Br], prepared from [Re(CO)₅Br] and H₂dhp in toluene, the H₂dhp ligand acts as a neutral bidentate N,N-donor chelate. The complexes were characterized by elemental analysis, infrared and ¹H NMR spectroscopy and X-ray crystallography.     

An easy access to diversely fused dioxa-2-aza-tricyclo[n.3.1.0]tetra/pentadecanes under solvent-free condition

Efficient syntheses of phenyl/N-heterocycle fused 6,13-dioxa-2-aza-tricyclo[8.3.1.0^2,8]tetradecanes have been accomplished from 8-hydroxy quinoline derivatives under solvent-free condition, using basic alumina as the solid support. The methodology was successfully extended for the synthesis of corresponding pentadecane derivatives under similar reaction conditions. In terms of its general applicability, product yield, reaction time and effortless separation techniques, the methodology is more valuable compared to the solution phase protocols.     

Quantum chemical analysis of possible fragmentation of [M + H]<Superscript>+</Superscript> and [M + Na]<Superscript>+</Superscript> complexes of monosubstituted methane,cyclohexane, and benzene derivatives in mass spectrometric studies

The formation and fragmentation energies of the proton and sodium cation complexes with monosubstituted methane, cyclohexane, and benzene derivatives in which carbon atoms are bonded to substituents (NH₂, OH, F, Cl, Br, ONO₂, NO₂, COOH, CN, and Ph) were calculated by the B3LYP/6-31G(d) method. For [M + Na]⁺ complexes, the formation energies are much lower (and differ from one another to a much lesser extent), while the dissociation energies are much higher, than the corresponding energies of the [M + H]⁺ complexes. Na⁺ cation shows a lower selectivity toward localization at functional groups in molecules compared to H⁺. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 246–249, February, 2008.     

Microwave-assisted separation of ionic liquids from aqueous solution of ionic liquids

Microwave-assisted separation has been applied to recover ionic liquid (IL) from its aqueous solution as an efficient method with respect to time and energy compared to the conventional vacuum distillation. Hydrophilic ILs such as 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF(4)]), 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([Bmim][TfO]) and 1-ethyl-3-methylimidazolium methylsulfate ([Emim][MS]) could be recovered in 6 min from the mixture of ILs and water (1:1, w/w) under microwave irradiation at constant power of 10 W while it took at least 240 min to obtain ILs containing same water content (less than 0.5 wt%) by conventional vacuum oven at 363.15 K with 90 kPa of vacuum pressure. Energy consumptions per gram of evaporated water from the homogeneous mixture of hydrophilic ILs and water (1:1, w/w) by microwave-assisted separation were at least 52 times more efficient than those in conventional vacuum oven. It demonstrated that microwave-assisted separation could be used for complete recovery of ILs in sense of time and energy as well as relevant purity.