109-88-6Relevant articles and documents
Tri-, tetra-, and hexanuclear mixed-valence molybdenum clusters: Structural diversity and catalysis of acetylene hydrogenation
Kuznetsov, Denis A.,Bazhenova, Tamara A.,Fedyanin, Ivan V.,Martynenko, Vyacheslav M.,Shestakov, Alexander F.,Petrova, Galina N.,Komarova, Natal'Ya S.
, p. 16309 - 16316 (2016)
A series of novel cluster compounds comprising molybdenum in a low valence state was synthesized by means of a disproportionation of the dimeric compound [Mo+42Cl4(OCH3)4(CH3OH)2] (1). The reaction of 1 with CH3OH leads to the disproportionation of Mo+4 yielding an unusual mixed-valence cluster [Mo+3.54Cl4O2(OCH3)6(CH3OH)4] (2). By exploring this synthetic approach further, tri-{[Mo3Cl3(OCH3)7(CH3OH)3] (3)}, tetra-{[Mo4Cl4(OCH3)10(CH3OH)2] (4), [Mo4Cl3O(OCH3)9(CH3OH)3] (5), [Mo4Cl2(OCH3)12(CH3OH)2] (6)}, and hexanuclear {[Mo6Cl4O6(OCH3)10(CH3OH)2] (7)} molybdenum alkoxides were synthesized by the reaction of 1 with methanol and stoichiometric amounts of magnesium methoxide, thus providing a general facile access to the polynuclear methoxide complexes of a low-valence molybdenum. Due to the feasibility to adopt multiple oxidation states in a reversible manner and the documented competence of molybdenum alkoxide compounds to catalyze the reduction of inert molecules, including N2, the synthesized compounds were expected to function as catalysts of small molecule substrates reduction/hydrogenation. Accordingly, the reduction of acetylene (C2H2) to an ethylene (C2H4) and ethane (C2H6) mixture, in methanol (with water additives) serving as a reaction medium and a proton donor, and using sodium or europium amalgams as reducing agents, was performed in the presence of 2. Preliminary kinetic studies evidently point to a catalytic function of molybdenum species derived from 2, thus establishing the observed reactivity as a rare example of non-precious metal-catalyzed acetylene hydrogenation, providing, in addition, a convenient model for further mechanistic studies.
Upgrading of furfural to biofuel precursors: Via aldol condensation with acetone over magnesium hydroxide fluorides MgF2- x(OH)x
Xu, Minrui,Célérier, Stéphane,Comparot, Jean-Dominique,Rousseau, Julie,Corbet, Matthieu,Richard, Frédéric,Clacens, Jean-Marc
, p. 5793 - 5802 (2019)
Wastes from lignocellulosic materials, especially hemicellulose, are extremely promising resources to produce fuels from renewable raw materials. Furfural, resulting from the depolymerization of hemicellulose, is often considered as an extremely interesting platform molecule. Particularly, new biofuels containing molecules with 8 and 13 carbon atoms can be produced from aldol condensation of furfural and acetone followed by a deoxygenation reaction. In this work, several magnesium hydroxide fluorides MgF2-x(OH)x were prepared by a sol-gel method with various F/Mg ratios (0 to 2) at 100 °C. All solid samples were fully characterized by several techniques (nitrogen adsorption-desorption, TEM, IR, XRD and ICP). MgF2-x(OH)x were mainly composed of an intimate mixture of MgF2 and Mg(OH)2-x(OCH3)x and exhibited both acid-base properties and high surface areas. From CO2 adsorption experiments, a basicity scale corresponding to basic sites with moderate strength was established: MgF1.5(OH)0.5 > MgF(OH) ~ MgF1.75(OH)0.25 > MgF0.5(OH)1.5 > Mg(OH)2 ? MgF2. It was proposed that the presence of fluorine allowed stabilization of the basic sites with moderate strength at ambient atmosphere. The aldol condensation of furfural and acetone was carried out under mild reaction conditions (50 °C, Patm) over MgF2-x(OH)x. These catalysts were involved in this reaction without using a classical activation step for basic solid catalysts, which constitutes a major advantage of energy conservation and thus, economic efficiency. The solid with a F/Mg ratio equal to 1.5 (MgF1.5(OH)0.5) exhibited the highest activity, the furanic dimer (1,5-di(furan-2-yl)penta-1,4-dien-3-one) being the main product. A good correlation between the catalytic activity and the basicity scale was highlighted. Based on these results, the nature of active sites was proposed: a combination of a Lewis acid site (coordinatively unsaturated metal site) in the vicinity of a basic site (hydroxyl groups of Mg(OH)2-x(OCH3)x). The effect of the furfural/acetone ratio on the catalytic properties of MgF1.5(OH)0.5 was also investigated.
Synthesis and Tubulin Binding of Novel C-10 Analogues of Colchicine
Staretz, Marianne E.,Hastie, Susan Bane
, p. 758 - 764 (1993)
A series of novel C-10 derivatives of colchicine have been prepared and evaluated for inhibition of in vitro microtubule assembly and of colchicine binding to tubulin.The C-10 substituent of colchicine was replaced by halogens, alkyl and alkoxy groups, and hydrogen.Many of these compounds are available by nucleophilic substitution of 10-fluoro-10-demethoxycolchicine (9) without concomitant formation of ring contraction products.Compound 9 is prepared by reaction of (diethylamino)sulfur trifluoride with colchicine.Unlike most reactions of colchicine, the colchicine rather than the isocolchicine regioisomer is the predominant product of this reaction.It was found that modification of the C-10 substituent of colchicine had a relatively minor effect on the potency of the colchicinoids.The electronic nature of the substituent had no significant effect on the efficacy of the compound, indicating that hydrogen bonding or polar interactions between the C-10 substituent of colchicinoids and an amino acid in the colchicine binding site on tubulin are not present in the colchicine-tubulin complex.A decrease in activity was observed with increasing length of the alkyl chain bonded to the C-10 position, but potency was less affected when the alkyl groups were positioned in close proximity to the C-10 carbon of the tropone ring.It is concluded that the steric rather than the electronic properties of the C-10 substituent are the predominant determinants of activity in this series.
Stereoselective synthesis of α-methyl and α-alkyl ketones from esters and alkenes: Via cyclopropanol intermediates
Barysevich, Maryia V.,Kazlova, Volha V.,Kukel, Aliaksandr G.,Liubina, Aliaksandra I.,Hurski, Alaksiej L.,Zhabinskii, Vladimir N.,Khripach, Vladimir A.
supporting information, p. 2800 - 2803 (2018/03/21)
Alkenes bearing a stereocenter in the allylic position were found to undergo Kulinkovich hydroxycyclopropanation with good diastereoselectivity. For the isomerization of the resulting cyclopropanols to diastereomerically enriched α-methyl ketones, a new mild regioselective method has been developed. A sequence of stereoselective cyclopropanation and cyclopropanol ring opening was successfully employed for the construction of the C20 stereocenter in steroids.
Polyfluorinated salicylic acid derivatives as analogs of known drugs: Synthesis, molecular docking and biological evaluation
Shchegol'kov,Trefilova,Borisevich,Shchur,Ljushina,Khursan,Burgart, Ya.V.,Solodnikov, S.Yu.,Saloutin,Markova,Maslova,Krasnykh
, p. 91 - 99 (2016/12/22)
We have developed the convenient methods for synthesis of polyfluorosalicylic acids and their derivatives. For the first time the biological properties of polyfluorosalicylates were investigated in vitro (permeability through the biological membranes, COX-1 inhibitory action) and in vivo (anti-inflammatory, analgesic activities, acute toxicity). Molecular docking of polyfluorinated salicylates confirmed in vitro and in vivo experiments.