A Simple and Efficient Synthesis of 12-Aryl-8,9,10,12- tetrahydrobenzo[a]xanthen-11-ones by ZnO Nanoparticles Catalyzed Three Component Coupling Reaction of Aldehydes, 2-Naphthol and Dimedone

Highly effective zinc oxide nanoparticles catalyzed solvent-free synthesis of some tetrahydrobenzo[a]xanthen-11-one derivatives via one-pot multi-component reaction of aldehydes, 2-naphthol and dimedone. The present approach creates a variety of biologically active heterocyclic compounds in excellent yields and short reaction times. Four new compounds are reported. The salient features of the ZnO nanoparticles are: easy preparation, cost-effective, high stability, low loading and reusability of the catalyst. The prepared zinc oxide nanoparticles were fully characterized by EDX, XRD, SEM, IR and TEM analysis.KEYWORDS: ZnO, nanoparticles, tetrahydrobenzo[a]xanthen-11-one, multi-component reactions,  heterocyclic compounds

FeCl 3 .nano SiO 2 : An Efficient Heterogeneous Nano Catalyst for the Synthesis of 14-Aryl-14H-dibenzo[a,j]xanthenes and 1,8-Dioxo-octahydro-xanthenes under Solvent-free Conditions

ABSTRACT A novel, efficient and eco-friendly procedure for the synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes and 1,8-dioxo-octahydroxanthenes is described through one-pot condensation of 2-naphthol and dimedone with aryl aldehydes in the presence of nano silica-supported ferric chloride under solvent-free conditions. The present approach offers several advantages such as short reaction times, high yields, easy purification, recovery and reusability of the catalyst

MILD AND EFFICIENT METHOD FOR OXIDATION OF ALCOHOLS IN IONIC LIQUID MEDIA

In this study the strong oxidative agent, potassium permanganate, has been moderated with using under ionic liquid media for selective oxidation of some benzylic and aliphatic alcohols to their corresponding carbonyl compounds under mild and green conditions. 1-Butyl-3-methylimidazoliumbromide ([bmim]Br) (BMIM) associated with acetonitrile has been employed as modified media for oxidation of benzylic alcohols. This chemoselective and efficient process produced aldehydes and ketones with higher purity and yields and shorter reaction period in [bmim]Br as ionic liquid than conventional solvents

Aqua­(1,10-phenanthroline)(pyridine-2,6-dicarboxyl­ato)nickel(II) pyridine-2,6-di­carboxylic acid solvate tetra­hydrate

The title compound, [Ni(C7H3NO4)(C12H8N2)(H2O)]·C7H5NO4·4H2O or [Ni(pydc)(phen)(H2O)].pydcH2·4H2O, was obtained by the reaction of nickel(II) nitrate hexa­hydrate with the proton-transfer compound (phenH)2(pydc) (phen is 1,10-phenanothroline and pydcH2 is pyridine-2,6-dicarboxylic acid) in aqueous solution. Both the cationic and anionic portions of the starting proton-transfer compound are involved in the complexation. The NiII atom has a distorted octa­hedral geometry and is hexa­coordinated by three O atoms and three N atoms from one phen fragment (as a bidentate ligand), one (pydc)2− unit (as a tridentate ligand) and one water mol­ecule. In the crystal structure, extensive O—H⋯O, O—H⋯N and C—H⋯O hydrogen bonds with D⋯A distances ranging from 2.573 (2) to 3.385 (2) Å, π–π inter­actions between the phen ring systems [with centroid–centroid distances of 3.4694 (12), 3.4781 (11) and 3.8310 (11) Å] and inter­molecular C—O⋯π inter­actions [C⋯π distances of 3.4812 (17), 3.5784 (16) and 3.5926 (16) Å] connect the various components together

Hexaaqua­nickel(II) tetra­aqua­bis­(μ-pyridine-2,6-dicarboxyl­ato)bis­(pyridine-2,6-dicarboxyl­ato)trinickelate(II) octa­hydrate

The title compound, [Ni(H2O)6][Ni3(C7H3NO4)4(H2O)4]·8H2O, was obtained by the reaction of nickel(II) nitrate hexa­hydrate with pyridine-2,6-dicarb­oxy­lic acid (pydcH2) and 1,10-phenanothroline (phen) in an aqueous solution. The latter ligand is not involved in formation of the title complex. There are three different NiII atoms in the asymmetric unit, two of which are located on inversion centers, and thus the [Ni(H2O)6]2+ cation and the trinuclear {[Ni(pydc)2]2-μ-Ni(H2O)4}2− anion are centrosymmetric. All NiII atoms exhibit an octa­hedral coordination geometry. Various inter­actions, including numerous O—H⋯O and C—H⋯O hydrogen bonds and C—O⋯π stacking of the pyridine and carboxyl­ate groups [3.570 (1), 3.758 (1) and 3.609 (1) Å], are observed in the crystal structure

Antioxidant activity of twenty wild Spanish Thymus mastichina L. populations and its relation with their chemical composition

The antioxidant activity and chemical composition of essential oils and methanolic extracts of twenty Spanish Thymus mastichina L. populations were studied. Both essential oils and methanolic extracts possessed antioxidant properties. However, the total phenol contents of the methanolic extracts varied between 2.90 and 9.15mg GAE/g extract and the EC 25 values of DPPH free radical scavenging activity between 0.90 and 3.45mg/mL for the methanolic extracts and 78-241mg/mL for essential oils, these showing low antioxidant potential. Actually, in essential oils the main compound determined was the 1,8-cineole (56.8-69.6%), whereas thymol, γ-terpinene, terpinolene and geraniol (species with considerable DPPH scavenging activity) were observed in low amounts. Concerning methanolic extracts, rosmarinic acid was the most abundant polyphenol (1.70-9.85mg/g), followed by methoxysalicylic acid, apigenin, kaempferol and luteolin.The authors are grateful to the POCTEPePrograma Cooperação Transfronteiriça España-Portugal 2007 e 2013 for financial support through the project “Mejora de la competitividad del sector agrario de Castilla y León y Norte de Portugal a través de la innovación y el desarrollo de productos diferenciados de alto valor”.info:eu-repo/semantics/publishedVersio