Synthesis of Functionalized Azepines via Cu(I)-Catalyzed Tandem Amination/Cyclization Reaction of Fluorinated Allenynes

An efficient method for the selective preparation of trifluoromethyl-substituted azepin-2-carboxylates and their phosphorous analogues has been developed via Cu(I)-catalyzed tandem amination/cyclization reaction of functionalized allenynes with primary and secondary amines

Synthesis of CF₃-Containing Spiro-[Indene-Proline] Derivatives via Rh(III)-Catalyzed C-H Activation/Annulation

An efficient method of accessing new CF3-containing spiro-[indene-proline] derivatives has been developed based on a Cp*Rh(III)-catalyzed tandem C-H activation/[3+2]–annulation reaction of 5-aryl-2-(trifluoromethyl)-3,4-dihydro-2H-pyrrole-2-carboxylates with alkynes. An important feature of this spiro annulation process is the feasibility of dehydroproline moiety to act as a directing group in the selective activation of the aromatic C-H bond

Direct arylation of C60Cl6 and C70Cl8 with carboxylic acids: a synthetic avenue to water-soluble fullerene derivatives with promising antiviral activity

We report unprecedented Friedel-Crafts arylation of chlorofullerenes C60Cl6 and C70Cl8 with unprotected carboxylic acids as an efficient single-step synthesis of the inherently stable water-soluble fullerene derivatives. Using this method, a series of previously unaccessible compounds was obtained without chromatographic purification in almost quantitative yields. Promising anti-HIV activity comparable to characteristics of commercial drugs was demonstrated for some of these compounds.status: publishe

Synthesis, characterization and anti-HIV activity of polycarboxylic [60]fullerene derivatives obtained in the reaction of C60Cl6 with a hydroquinone ethere

status: publishe

Methylsulfanyl-Stabilized Rotamers of Cobalt Bis(dicarbollide)

Methylsulfanyl derivatives of cobalt bis(dicarbollide), [8,8â\u80²-(MeS)2-3,3â\u80²-Co(1,2-C2B9H10)2]â\u80\u93, [4,4â\u80²-(MeS)2-3,3â\u80²-Co(1,2-C2B9H10)2]â\u80\u93, and [4,7â\u80²-(MeS)2-3,3â\u80²-Co(1,2-C2B9H10)2]â\u80\u93, were synthesized through the reactions of CoCl2with [10-MeS-7,8-C2B9H11]â\u80\u93and [9-MeS-7,8-C2B9H11]â\u80\u93in strong alkaline aqueous media. The 4,4â\u80²-(rac) and 4,7â\u80²-(meso) isomers were separated by column chromatography as the tetrabutylammonium salts. The structures of [Bu4N][8,8â\u80²-(MeS)2-3,3â\u80²-Co(1,2-C2B9H10)2], [Bu4N][4,4â\u80²-(MeS)2-3,3â\u80²-Co(1,2-C2B9H10)2], and [Bu4N][4,7â\u80²-(MeS)2-3,3â\u80²-Co(1,2-C2B9H10)2] were determined through single-crystal X-ray diffraction. In the solid state, the rotation of the two dicarbollide ligands with respect to each other is hampered by the formation of intramolecular CH···S(Me) hydrogen bonds between the ligands, and this results in the stabilization of definite rotamers, namely, the transoid conformation for the 8,8â\u80² isomer and the gauche conformations for the 4,4â\u80² and 4,7â\u80² isomers. These data are in a good agreement with the results of quantum-chemical calculations

Thiophene-based water-soluble fullerene derivatives as highly potent antiherpetic pharmaceuticals

Here we report the Friedel-Crafts arylation of chlorofullerenes C60Cl6 and C70Cl8 with thiophene-based methyl esters. While C60Cl6 formed expected Cs-C60R5Cl products, C70Cl8 demonstrated a tendency for both substitution of chlorine atoms and addition of an extra thiophene unit, thus forming Cs-C70R8 and C1-C70R9H compounds. The synthesized water-soluble C60 and C70 fullerene derivatives with thiophene-based addends demonstrated high activity against a broad range of viruses, including human immunodeficiency virus, influenza virus, cytomegalovirus, and herpes simplex virus. The record activity of C70 fullerene derivatives against herpes simplex virus together with low toxicity in mice makes them promising candidates for the development of novel non-nucleoside antiherpetic drugs.status: publishe

Synthesis and structure of bis(methylsulfanyl) derivatives of iron bis(dicarbollide)

Bis(methylsulfanyl) derivatives of iron(II) bis(dicarbollide) [8,8′-(MeS)2-3,3′-Fe(1,2-C2B9H10)2]2- (42−), [4,4′-(MeS)2-3,3′-Fe(1,2-C2B9H10)2]2- (52−), and [4,7′-(MeS)2-3,3′-Fe(1,2-C2B9H10)2]2- (62−) were prepared by the treatment of the corresponding dimethylsulfonium derivatives 1–3 with potassium butylthiolate. Their oxidation by air in aqueous solution results in the corresponding derivatives of iron(III) bis(dicarbollide) [8,8′-(MeS)2-3,3′-Fe(1,2-C2B9H10)2]- (7-), [4,4′-(MeS)2-3,3′-Fe(1,2-C2B9H10)2]- (8-) and [4,7′-(MeS)2-3,3′-Fe(1,2-C2B9H10)2]- (9-). The structures of (Bu4N)2[8,8′-(MeS)2-3,3′-Fe(1,2-C2B9H10)2] and (Me4N)[4,7′-(MeS)2-3,3′-Fe(1,2-C2B9H10)2] were determined through single-crystal X-ray diffraction. In the solid state, the rotation of the dicarbollide ligands with respect to each other is hampered due to formation of weak intramolecular CH⋯S(Me) hydrogen bonds between the ligands resulting in stabilization of transoid-conformation in the case of 8,8′-isomer and gauche-conformation in the case of 4,4′-and 4,7′-isomers. The synthesized bis(methylsulfanyl) derivatives of iron bis(dicarbollide) can be considered as a versatile platform for design of molecular switches

Regiospecific C–N Photocyclization of 2‑Styrylquinolines

Regiospecific C–N photocyclization of 2-styrylquinolines resulting in formation of potentially biologically active quino­[1,2-<i>a</i>]­quinolizinium derivatives was investigated. The presence of strong electron-donating groups in the phenyl ring reveals to be a crucial factor managing photocyclization effectiveness. Introduction of a crown ether moiety allows changing the photoreaction parameters by means of complexation with Mg­(ClO₄)₂

Distorted <i>commo</i>-Cobaltacarboranes Based on the 5,6-Dicarba-<i>nido</i>-decaborane(12): The First Bimetal Cobalt–Copper Zwitterion-Containing Cluster with Four (B–H)₄···Cu Bonds Not Showing Fluxional Behavior in Solution

Treatment of a recently reported complex [Ph₄P]­[<i>closo,nido-</i>CoH­(2,4-C₂B₈H₁₀)­(7,8-C₂B₈H₁₁)] (<b>1</b>) either by H₂O₂ in acetone or NaH in THF leads to the loss of both the bridging and terminal hydrides yielding the diamagnetic salt of an anionic <i>commo</i>-cobaltacarborane [Ph₄P]­[Co­(2,4-<i>isonido</i>-C₂B₈H₁₀)₂] (<b>2</b>) with the {CoC₂B₈}-cluster units adopting a distorted skeletal geometry of the <i>isonido</i>-type. The anionic <i>commo</i> complex <b>2</b> reacts with in situ generated cationic [CuPPh₃]⁺ species to give stable copper–cobalt zwitterion [Ph₃PCu]­[Co­(2,4-<i>isonido</i>-C₂B₈H₁₀)₂] (<b>3</b>) with four two-electron, three-center (B–H)₄···Cu bonds, and exhibits no fluxional behavior in solution. Complex <b>3</b>, at the same time, in CH₂Cl₂ in the presence of 2-fold excess of PPh₃ readily converts to a new anionic species [(Ph₃P)₃Cu]­[Co­(2,4-<i>isonido</i>-C₂B₈H₁₀)₂] (<b>4</b>) which retains initial <i>isonido</i> geometry. All newly obtained diamagnetic <i>commo</i> complexes were characterized by a combination of analytical and multinuclear NMR spectroscopic data and by single-crystal X-ray diffraction studies of complexes <b>2</b> and <b>3</b>