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Boron Trifluoride-Promoted Activation of Water by Bis(tricyclohexylphosphine)palladium(0).
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Checklist della flora vascolare psammofila della Toscana
No full textChecklist of the psammophilous vascular flora of Tuscany. An updated list of the psammophilous vascular flora occurring in coastal areas of Tuscany is presented. The list is based on bibliographic analysis and field studies effected ad hoc in the year 2012-2013. 704 specific and infraspecific taxa are reported (641 native). They belong to 383 genera and 90 families. Most represented families are Poaceae (13%), Asteraceae (12%), Fabaceae (10%), Caryophyllaceae (5%), Apiaceae (4%). 63 units are naturalized exotic species (about 9% of the flora). Aloe arborescens is a casual exotic newly recorded for Tuscany. The Italian endemics are 6, of which three are exclusive of sandy Tuscan coasts (Centaurea aplolepa Moretti subsp. subciliata (DC.) Arcang., Limonium etruscum Arrigoni & Rizzotto, Solidago litoralis Savi). Only 11 taxa were recorded in all or almost all the study areas: Ammophila arenaria (L.) Link subsp. arundinacea H.Lindb, Cakile maritima Scop. subsp. maritima, Calystegia soldanella (L.) Roem. & Schult., Echinophora spinosa L., Eryngium maritimum L., Kali tragus (L.) Scop. s.l., Lagurus ovatus L. subsp. ovatus, Medicago marina L., Pancratium maritimum L., Sporobolus virginicus Kunth
Notula: 187. Drosanthemum floribundum (Aizoaceae). In: Barberis G., Nepi C., Peccenini S., Peruzzi L. (eds.), Notulae alla flora esotica d'Italia: 9
No full textReactivity of cationic molybdenum(II) complexes. Part 3. Synthesis of methoxide and carbomethoxide derivatives of -pentamethylcyclopentadienyl–molybdenum(II) and the crystal structure determination of the oxidation product trans-[{Mo(-C5Me5)(O)2}2(μ-O)]
No full textThe complex [Mo(CO)3(η-C5Me5){P(OMe)3}]BF4 (1) reacts in methanol solution with Na(OMe) to give a mixture of cis- and trans-[Mo(CO)2(η-C5Me5){P(OMe)3}(CO2Me)](3). Compound (3) decarbonylates at room temperature in various solvents giving a mixture of cis- and trans-[Mo(CO)2(η-C5Me5){P(OMe)3}(OMe)] (4). The complex [Mo(CO)3(η-C5Me5)] BF4 (2) reacts in methanol solution with Na(OMe) affording the insoluble complex [{Mo(CO)2(η-C5Me5)(OMe)}n] (5) which is monomerized by reaction with P(OMe)3 in refluxing tetrahydrofuran (thf); trans-(4) is the main product of this reaction. Oxidation of a thf suspension of [{Mo(CO)2(η-C5Me5)(OMe)}n] by oxygen gives the Mo(VI) derivative [{Mo(η-C5Me5)(O)2}2(μ-O)] (6), together with unidentified products. The X-ray crystal structure of (6) has been established: (6) is monoclinic, space group P21/a, a= 17.677(6), b= 9.248(1), c= 21.272(6)Å, β= 101.68(2)°, Z= 6
Catalytic hydrogenation for the industrial synthesis of the Wong's anthracyclines intermediate
No full textA new catalytic synthesis of the Wong's ant.racyclines intermediate, (R)-2-acetyl-2-hydroxy-5,8-dimethoxy-1,2,3,4-tetrahydronapthlene, starting from the corresponding 1,2-diol has been discovered through its selective hydrogenolysis in the presence of palladium heterogeneous catalysts. High yield and no racemization were found under mild reaction conditions: the molar selectivity towards the target product was always higher than 99.5%. The catalytic performances resulted strongly dependent on the nature of the palladium catalyst, unreduced Pd/C showing the best performances. This straightforward catalytic route significantly improves the up to now adopted industrial process. (c) 2006 Elsevier B.V. All rights reserved
Selective catalytic hydrogenolysis for the efficient synthesis of Wong tetraline, a key intermediate for anthracyclines
No full textOxidative Addition of O-H Bond to a Metal Center - Synthesis and Crystal-Structure of trans-(PhO)(H)Pd(PCY3)2.PhOH
No full text(Cy3P)2Pd (Cy = C6H11) reacts with PhOH in toluene to give the phenoxopalladium(II) hydride derivative trans-(PhO)(H)Pd(PCy3)2 . PhOH; the crystal structural study has established that the oxygen of the phenoxy group forms a hydrogen bridge with an uncoordinated phenol molecule, and has allowed direct location of the hydride atom (Pd-H, 1.57(2) angstroem
Efficient enantioselective synthesis of (R)-2-acetyl-2-hydroxy-5,8-dimethoxy-1,2,3,4-tetrahydronaphthalene, the key intermediate in the synthesis of anthracycline antibiotics
No full textA simple, efficient, enantioselective synthesis of (R)-2-acetyl-2-hydroxy-5,8-dimethoxy-1,2,3,4-tetrahydronaphthalene, the key intermediate in the synthesis of anthracycline antibiotics, is described. The synthetic procedure starts with the Sharpless asymmetric dihydroxylation of 2-acetyl-5,8-dimethoxy-3,4-dihydronaphthalene: the diol obtained is regioselectively transformed into the corresponding chloroacetate which is dehalogenated and saponified to give the desired title compound in four steps with satisfactory yield (52%). No separation step is necessary at any point of the synthetic process. An efficient procedure for the synthesis of the starting enone and the stereoselectivity of the methanolysis of the intermediate chloroacetate are also reported. © 2002 Elsevier Science Ltd. All rights reserved
Oxidative addition of phenols to bis(tricyclohexylphosphine)palladium. Synthesis and structural characterization of trans-[Pd(PCy3)2(H)(OC6H5)].C6H5OH (1) and trans-[Pd(PCy3)2(H)(OC6F5)].C6F5OH (2)
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