Search results for " Synthesis"
showing 10 items of 1625 documents
Synthesis and characterization of some dibutylbis{5-[(E)-2-(aryl)-1-diazenyl]-2-hydroxybenzoato}tin(IV) compounds. Toxicity studies of di- and tri-or…
2003
The preparation and spectroscopic characterization of some complexes of the type Bu2Sn(LH)2 (LH = 5-[(E)-2-(aryl)-1-diazenyl]-2-hydroxybenzoate) are reported. On the basis of spectroscopic evidence (1H, 13C, 119Sn NMR, IR and 119mSn Mossbauer) the compounds were judged to adopt the usual dicarboxylato structural type with a skew trapezoidal arrangement. This was further confirmed by X-ray crystallography in the case of Bu2Sn(L5H)2 (L5H = 5-[(E)-2-(4-chlorophenyl)-1-diazenyl]-2-hydroxybenzoate). Toxicity studies of the di- and tri-organotin compounds on the second larval instar of Aedes aegypti mosquito larvae are reported. Copyright © 2003 John Wiley & Sons, Ltd.
Microwave-Assisted Synthesis of New Selenazole Derivatives with Antiproliferative Activity
2013
New aryl-hydrazinyl-1,3-selenazole and aroyl-hydrazonyl-1,3-selenazoles were synthesized via Hantzsch type condensation reactions of selenosemicarbazides with α-halogenocarbonyl derivatives, under classical versus microwave heating conditions. Excellent yields and shorter reaction times were obtained under irradiation conditions. The structures of the synthesized compounds were assigned based on spectroscopic data (FT-IR, 1 H-NMR), MS and elemental analysis. Selenazole derivatives were screened for their anti-proliferative effects against two leukemia cell lines (CCRF-CEM and HL60) and three carcinoma cell lines (MDA-MB231, HCT116 and U87MG).
Solution versus Fluorous versus Solid-Phase Synthesis of 2,5-Disubstituted 1,3-Azoles. Preliminary Antibacterial Activity Studies
2009
A small library of compounds with an oxa(thia)zole scaffold and structural diversity in both positions 2 and 5 has been synthesized. Double acylation of a protected glycine affords intermediate α-amido-β-ketoesters, which in turn can be dehydrated to afford 1,3-oxazoles or reacted with Lawesson’s reagent to furnish 1,3-thiazoles. This procedure was designed with its adaptation to fluorous techniques in mind. Thus, when a protected glycine with a fluorous tag in the ester moiety is used as a starting material, the synthesis can be easily completed without column chromatography purification of intermediate compounds with good to excellent yields, thus affording a suitable entry to the prepara…
Synthesis and in vitro antimicrobial activities of new (cyano-NNO-azoxy) pyrazole derivatives
2011
The antibacterial and antifungal activity of a series of products, in which the 1,5-dimethyl-4-(cyano- NNO-azoxy)pyrazol-3-yl and 1,3-dimethyl-4-(cyano-NNO-azoxy)pyrazol-5-yl moieties were linked to pyridine, pyrazole, isoxazole, thiophene and the furan ring, were examined. No molecule displayed activity against the Gram-negative bacteria tested. Conversely, some compounds displayed activity against two Staphylococcus aureus strains, including the methicillin resistant strain. All compounds displayed interesting antifungal activity, the most active compound of the series being the thiophene derivative 7a. This compound’s activity against Candida krusei and Candida glabrata (MIC = 0.25 and 0…
DESIGN, SYNTHESIS, AND BIOLOGICAL EVALUATION OF NOVEL HETEROCYCLIC DERIVATIVES AS MODULATORS OF B-DNA AND G-QUADRUPLEXES DNA FUNCTIONS
Preparation and Characterization of P2 BCh Ring Systems (Ch=S, Se) and Their Reactivity with N-Heterocyclic Carbenes
2018
Four-membered rings with a P2BCh core (Ch = S, Se) have been synthesized via reaction of phosphinidene chalcogenide (Ar*P=Ch) and phosphaborene (Mes*P=BNR2). The mechanistic pathways towards these rings are explained by detailed computational work that confirmed the preference for the formation of P–P, not P–B, bonded systems, which seems counterintuitive given that both phosphorus atoms contain bulky ligands. The reactivity of the newly synthesized heterocycles, as well as that of the known (RPCh)n rings (n = 2, 3), was probed by the addition of Nheterocyclic carbenes, which revealed that all investigated compounds can act as sources of low-coordinate phosphorus species. peerReviewed
On-surface Synthesis of a Chiral Graphene Nanoribbon with Mixed Edge Structure.
2020
Abstract Chiral graphene nanoribbons represent an important class of graphene nanomaterials with varying combinations of armchair and zigzag edges conferring them unique structure‐dependent electronic properties. Here, we describe the on‐surface synthesis of an unprecedented cove‐edge chiral GNR with a benzo‐fused backbone on a Au(111) surface using 2,6‐dibromo‐1,5‐diphenylnaphthalene as precursor. The initial precursor self‐assembly and the formation of the chiral GNRs upon annealing are revealed, along with a relatively small electronic bandgap of approximately 1.6 eV, by scanning tunnelling microscopy and spectroscopy.
High-performing Sn-Co nanowire electrodes as anodes for lithium-ion batteries
2012
Abstract The preparation of Sn 2 Co 3 nanowire arrays (NWs) electrogrown inside the channels of polycarbonate membranes and their characterization as anodes for Li-ion batteries both in half-cell vs. Li and in battery configuration are reported. The Sn 2 Co 3 NW electrodes tested by deep galvanostatic charge/discharge cycles in ethylene carbonate-dimethylcarbonate (1:1) – LiPF 6 1 M displayed 80% capacity retention after 200 cycles at C/2 and 30 °C, and a high charge and discharge rate capability at C-rate from C/3 (0.33 A/g) to 10C (10 A/g) at 30° and 10 °C. Electrodes with the highest alloy loading delivered up to 0.6 mAh cm −2 at C/2. The performance of these electrodes in battery config…
Acene-type donors bearing one 1,3-dithiole ring
1999
Abstract A series of acene-type donors bearing only one 1,3-dithiole ring have been synthesized by following a Wittig-Horner reaction from 7 H -benz[ d,e ]anthracen-7-one and several phosphonate esters. The excellent donor properties have been studied using both experimental techniques and quantum-chemical calculations and reveal that the extraction of the first electron in the oxidation process occurs from the dithiole ring (0.42 e) and the acene unit (0.58 e).
ChemInform Abstract: Enantioselective Synthesis of Herbertane Sesquiterpenes: Synthesis of (-)-α-Formylherbertenol.
2010
Abstract The synthesis of 4-hydroxy-3-[(1 S )-1,2,2-trimethylcyclopentyl]benzaldehyde [(−)-α-formylherbertenol 1 ], a herbertane-type sesquiterpene isolated from the leafy liverwort Herberta adunca , from β-cyclogeraniol is described. The synthesis is based on the previously described preparation of an enantiopure 1,2,2-trimethylcyclopentane synthon from which the characteristic aromatic moiety of 1 is elaborated, using a Robinson annulation and a palladium-catalysed methoxycarbonylation of an aryl triflate as key synthetic steps. The synthesis of the natural sesquiterpene (−)-α-herbertenol, also a natural sequiterpene, using the same methodology is also described.