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The synthesis of enantiomerically enriched 7- and 8-hydroxy­stearic acids (7- and 8-HSA) has been successfully accomplished starting from chiral nonracemic 1-pentadecen-4-ol and 1-tetradecen-4-ol, respectively. Their Yamaguchi’s esterification with 4-pentenoic and 5-hexenoic acids, respectively, afforded the suitable dienic esters which were submitted to ring-closing metathesis reaction. After hydrogenation and basic hydrolysis of the complex reaction mixture, chiral nonracemic 7- and 8-HSA were obtained in about 40% total yield.

A simple and regioselectively controlled method for the preparation of both 1,4- and 1,6-regioisomers of 1-substituted 4(6)-trifluoromethyl-pyrimidin-2(1H)-ones is described. Both regioisomers were synthesized from the cyclocondensation reaction of 4-substituted 1,1,1-trifluoro-4-methoxybut-3-en-2-ones: with nonsymmetric ureas for the 1-substituted 4-(trifluoromethyl)pyrimidin-2(1H)-ones (1,4-isomer) and with nonsymmetric 1-substituted 2-methylisothiourea sulfates for the synthesis of 1-substituted 6-(trifluoromethyl)pyrimidin-2(1H)-ones (1,6-isomer). Each method furnished only the respective isomer in very good yields. The structure of the products was assigned based on the 1H and 13C NMR as well as 2D HMBC spectral analysis.

One of the most studied properties of novel organic solvents is represented by their use as media for many chemical reactions. In this field Ionic Liquids (ILs) and more recently Deep Eutectic Solvents (DESs) have been playing significant roles for their smart properties. DESs are increasing their relevance thanks to their low toxicity, and because of their simple and cheap preparation that can be carried out by simply mixing two compounds. In this work we present the studies of the use of an acid DES obtained from 3-(cyclohexyldimethylammonio)propane-1-sulfonate and (1S)-(+)-10-camphorsulfonic acid (SB3-Cy/CSA) as reaction media and catalyst for carbon–carbon bond formation reaction via Claisen–Schmidt condensation. This powerful and widely used aldol condensation was performed without the use of any catalysts that are usually needed in this reaction, because of the presence of acid CSA in the DES components. We synthesised fourteen substituted chalcones from benzaldehydes and substituted benzaldehydes in combination with acetophenone and substituted acetophenones as probe reactions. The advantages of the use of this DES in this relevant reaction are represented by: the green properties of the media and its low toxicity; the absence of harmful acids to catalyse the aldol condensation because of the camphorsulfonic acid composing the DES mixture; the recycling and the re-use of the DES in subsequent reaction cycles; the mild conditions and the excellent conversions and yields observed.

2-Piperidinones are synthesized in a single step from imines and 2-cyano glutaric anhydrides. The reaction provides the products in good diastereoselectivity and generates a quaternary stereogenic center. Substitutions on the anhydride skeleton are well tolerated to provide 2-piperidinones with three stereogenic centers from a single transformation. The pertinent transition structures have also been computed using quantum mechanics and reveal the key interactions controlling the stereochemical outcome of the reaction.

A self-catalyzed aza-Henry addition of ethyl nitroacetate on N-alkyl trifluoromethyl aldimines was reported to synthesize β-amino α-nitro trifluoromethyl esters, precursors of α,β-diamino acid derivatives. In the presence of a resident chiral center on the imine nitrogen, the use of a suitable Lewis acid leads to a good stereofacial control, always resulting from a nucleophilic unlike attack. By starting from optically pure N-protected trifluoromethyl aldimines or directly from N-α-amino ester trifluoromethyl aldimines, small ψ[CH(CF3)NH]-peptidomimetic backbones can be achieved in which a new primary amine function represents a possible center for synthetic extension. Finally, a very interesting, and never observed before, palladium-catalyzed syn β-elimination occurred, leading to the selective nitro group reduction reaction on the syn-α-amino ester functionalized aza-Henry adducts and obtaining more stable optically pure trifluoromethyl conjugated imines.

Unprecedented domino oxidative cyclization reactions of unprotected 2-alkynylanilines to give functionalized 4H-benzo[d][1,3]oxazin-4-one or benzisoxazole derivatives in moderate to good yields are achieved by silver vs. gold selective catalysis. The search for the optimal reaction conditions revealed the divergent catalytic activity of NaAuCl4·H2O and AgNO3.

A thorough transport and thermodynamic investigation of flux-grown single crystals of the ternary Zintl phase Yb 11 AlSb 9 , combined with first-principles density functional theory calculations, shows that this compound is a metal above T ≈ 100 K and a semiconductor with small hybridization gap at low- T . The general behavior resembles those of Kondo lattice semiconductors, although some of the measured properties are strongly sample dependent, as often seen in hybridized f -electron materials. We thus suggest that Yb 11 AlSb 9 can be considered as a new Yb-based Kondo lattice semiconductor joining the family of strongly correlated electron systems.

Review: synthesis of sulfur and nitrogen (half-)mustard carbonate analogs and their reactivity as novel, green electrophiles

A mild, sequential multicomponent reaction strategy for the regioselective synthesis of functionalized pentasubstituted pyrroles from readily accessible primary amines, 1,2-diaza-1,3-dienes, and 2,3-allenoates, has been developed. The process allows a [1N+2C+2C] annulation to be achieved through two sequential hydroamination reactions followed by an enamine-carbocyclization. Moreover, allenoates, as synthetic equivalents of monoactived alkynes, permit the specific preparation of multifunctionalized pyrroles.

The optimized conditions are applied to the preparation of a series of 2- or 3-substituted indole structures bearing additional functions at the arene part.

The reaction of acyclic and cyclic β-keto esters, substituted at the methylene group, with N-protected trifluoromethyl aldimines is investigated under conditions A).

Macrocyclic ligands are relevant because of the properties they impart to transition metal complexes, such as enhanced thermodynamic stability and slowed substitution kinetic behavior. Here, we address issues not previously reviewed, revisit others, present new results, and review and discuss the results obtained in the last decade for ruthenium(II/III) complexes with tetraazamacrocycles (mac) such as cyclam (1,4,8,11-tetraazacyclotetradecane), [RuL1L2(mac)]q+ with emphasis on nitrosyls. Topics include synthesis, macrocycle functionalization, structure, spectroscopy, photochemistry, reactivity, density functional theory calculations, and biological properties. [RuL1L2(mac)]q+ complexes exhibit a rich chemistry, sometimes unusual, which depends on macrocycle ring size, the presence of N- or C-pendant groups, metal oxidation state, electronic structure, and the nature of L1 and L2. These same features can be used to tune the properties of the complexes leading to potential applications in diverse fields.

A simple one-pot procedure for the preparation of symmetrical bis-hydrazone functionalized barbiturates, and a step-by step sequence for the synthesis of analogous unsymmetrical derivatives were developed. Their treatment in acid conditions furnish the symmetrical- and unsymmetrical-spirobarbiturate-pyridines, respectively.

This review is aimed at updating the current advance of metal complexes bearing acylpyrazolonate ligands. Novel synthetic procedures for acylpyrazolones are reported together with a survey of the ligands biological properties. All the literature since 2005 on metal complexes (main group, transition, lanthanide and actinide metals) containing acylpyrazolones is reported together with a discussion on their main structural features and field of potential applications.

A study of the palladium-catalyzed hydroarylation/hydrovinylation reaction of γ-(2-methoxycarbonylphenyl)propargylic alcohols with aryl iodides/vinyl triflates and of the rhodium-catalyzed one with organoboron derivatives is described. The opposite regiochemical outcome of the two processes allows an easy selective approach to 5- or 4-substituted benzoxepin-1(3H)-ones by combining the hydroarylative/hydrovinylative step with cyclocondensation between −OH and −COOMe groups in the intermediate γ,γ-disubstituted or β,γ-disubstituted allylic alcohols. A one-flask procedure to give benzo[c]oxepin-1(3H)-ones directly from the starting alkyne has been also developed. Treatment of crude γ,γ-disubstituted allylic alcohols with NaOH, followed by acidification, affords 3,3-disubstituted phthalides.

A novel synthesis method for the preparation of Cu2ZnSnS4 nanocrystals is presented using a liquid precursor of tin, namely tin(II) 2-ethylhexanoate, which yields small and nearly monodisperse NCs either in the kesterite or in the wurtzite phase depending on the sulfur source (elemental sulfur in oleylamine vs. dodecanethiol).

A variety of 2-substituted 5-alkynyl-1H-imidazoles were easily prepared by a one-pot sequential procedure involving a highly regioselective electrophilic C-5 bromination of 1,2-dimethyl-1H-imidazole, 2-chloro-1-methyl-1H-imidazole, and 2-aryl-1-methyl-1H-imidazoles, followed by an efficient palladium/copper co-catalyzed Sonogashira-type alkynylation.

Di-2-pyridyl carbonate (I) reacts with various alcohols to form mixtures of 2-pyridyl carbonates (III) or (VIII) and 2-oxopyridine-1-carboxylates (IV) and (IX).

The NaH-catalyzed Michael addition of N-arylhydrazones (II) with 1,2-diaza-1,3-dienes leads to novel β-azohydrazones (III), which are converted into hydroxyl pyrazoles (IV) by a ring closure reaction in the presence of a stoichiometric amount of NaH.

Starting from inexpensive cinnamic acids, a novel chemoenzymatic cascade one-pot approach to D-phenylalanine derivatives is developed.

The novel one-pot multicomponent reaction is based on the reaction of N-alkyl-N-(1H-indol-2-ylmethyl)amines, with various carbonyl compounds, such as aldehydes including formaldehyde or cyclohexenone, and variously functionalized isocyanides.

A NiFe layered double hydroxide (LDH) co-catalyst coated Ta3N5 nanorod electrode is fabricated by vapor deposition of Al on a Ta foil followed by anodizing the Al layer in oxalic acid, (40 V, 0.5 h), pore widening of the as-prepared porous Al2O3 by immersion in 5% aq.

Stereoselective synthesis of previously unreported (triazolyl)methylboronic acids is achieved from azidomethylboronates by copper-catalyzed azide—alkyne cycloaddition reaction.

It is found that the best conditions for this solventless Heck reaction are microwave irradiation in combination with an ionic liquid.

A regioselective inverse electron-demand hetero-Diels-Alder reaction of in situ generated 1,2-diaza-1,3-dienes with methoxyallene is developed.

The practical two-step reaction sequence is based on a Michael addition/cyclization approach.

The sequential three component reaction of acyl chlorides, isocyanides, and silver carboxylates affords moderately stable keto-iminoanhydrides which spontaneously undergo a Mumm rearrangement to produce the target α-ketoimides (IX) and (XI).

Reaction of trifluoroacetylated Kabbe adducts (IV) with phenylhydrazine or methylhydrazine proceeds with apposite regioselectivity furnishing chromenopyrazoles (VI) or (VIII), respectively.

This review represents a comprehensive attempt to summarize and discuss various sensing applications of iron oxide nanoparticles (NPs), which have attracted a great deal of attention over recent years because of their easy preparation, biocompatibility, nontoxicity, and broad range of biomedical applications. We review the application potential of nanomagnetite based amperometic sensors possessing an intrinsic enzyme mimetic activity similar to that found in natural peroxidases. In addition, we discuss the properties and applications of enzymatic sensors exploiting glucose oxidase, tyrosinase, and other enzymes for sensing a variety of important biomedical species. Among iron oxide-based nanocomposites, we highlight the use of Fe3O4@Au hybrids for designing new electrochemical aptasensors with unique versatility for binding diverse targets, including proteins and peptides. Similarly, sensing applications of composites of iron oxide NPs with graphene derivatives and carbon nanotubes are reviewed. A large p...

A direct access to an unexplored family of 5-hydroxymethylfurfural (HMF)-based acylhydrazones displaying antitumor activity is given.

A new type of catalyst containing (biaryl)methanol side chains in a chiral BINAP-disulfonamide skeleton is designed and synthesized.

This review with 387 references covers the literature until the end of November 2013 on the synthesis of multiply arylated heteroarenes via highly selective palladium-catalyzed direct C–H arylation reactions of heteroarene derivatives with aryl halides or pseudohalides or aryliodonium salts. Particular attention has been made to describe the synthesis of biologically active compounds and substances that are privileged structural motifs in organic materials. The practicality, versatility, and limitations of the various developed arylation protocols are discussed. 1 Introduction 2 Synthesis of Multiply Arylated Five-Membered Hetero­arenes with One Heteroatom 2.1 Multiply Arylated Furan and Benzo[b]furan Derivatives 2.2 Multiply Arylated Thiophenes and Benzo[b]thiophene Derivatives 2.3 Multiply Arylated Pyrrole and Indole Derivatives 3 Synthesis of Multiply Arylated Five-Membered Hetero­arenes with Two or More Heteroatoms 3.1 Multiply Arylated Pyrazole and 2H-Indazole Derivatives 3.2 Multiply Arylated Isoxazole Derivatives 3.3 Multiply Arylated Oxazole Derivatives 3.4 Multiply Arylated Thiazole and Thiazole N-Oxide Derivatives 3.5 Multiply Arylated Imidazole and Imidazole N-Oxide Derivatives­ 3.6 Multiply Arylated 1,2,3-Triazole and 1,2,3-Triazole N-Oxide Derivatives 3.7 Diarylated 1,2,4-Triazole and 1,3,4-Thiadiazole Derivatives 3.8 Diarylated Sydnone, 2,1,3-Benzothiadiazole, and Tetrazole Derivatives 4 Synthesis of Multiply Arylated Six-Membered Hetero­arenes 4.1 Diarylated Pyridines, Pyridine N-Oxides, and Pyrazine N-Oxides 5 Synthesis of Multiply Arylated Compounds Formed by Five-Membered Heteroarenes Fused to Five-Membered Heteroarenes 5.1 Diarylated Thieno[2,3-b]thiophenes, Imidazo[1,2-b]pyrazoles, and Thiazolo[3,2-b]-1,2,4-triazoles 6 Synthesis of Multiply Arylated Compounds Formed by Six-Membered Heteroarenes Fused to Five-Membered Hetero­arenes 6.1 Diarylated Indolizines, Pyrimido[5,4-b]indolizines, Pyrrolo[2,3-b]pyridines, Pyrazolo[1,5-a]pyrimidines, Imidazo[1,2-a]pyridines, Imidazo[1,5-a]pyridines, Xanthines, Imidazo[1,2-b]tetrazines, Imidazo[1,2-a]pyrazines, and ­Furo[3,2-b]pyridines 7 Conclusions

The field of flame retardancy for polymeric materials (i.e. plastics, foams and in particular textiles) is currently facing several changes and challenges because some of the current halogenated or phosphorus-based flame retardants (FRs) have proven to be persistent, bioaccumulative, carcinogenic and/or toxic for animals and humans. Thus, the search for highly efficient green flame retardant products, which are exploitable by using simple and environmentally-friendly techniques (i.e. impregnation/exhaustion, layer-by-layer), is driving the researchers towards the development of worthy alternatives. In this context, very recently, biomacromolecules (in particular proteins and deoxyribonucleic acid) have been thoroughly investigated because they exhibit significant potentials as novel green FRs for selected fabrics (cotton, polyester and their blends), as well as for bulk polymers (ethylene vinyl-acetate copolymers) and foamed polyurethane substrates. This work aims to review our recent results related to the “unconventional” use of these biomacromolecules as FRs with low-environmental impact for fabric substrates, as well as the challenges and the perspectives that these products may offer in the forthcoming years in the field of flame retardancy for textiles. To provide the basic knowledge necessary for understanding the role of biomacromolecules as FRs for textiles to the readers, first of all the description of the structure, main properties and conventional applications of proteins and deoxyribonucleic acid is provided; the thermal and thermo-oxidative stability, the reaction to a flame exposure or to an irradiative heat source of the selected fabrics – cotton, polyester and their blends – will be discussed, as well.

The new title compound is prepared by solid state reaction of a stoichiometric mixture of PbO, MnCO3, and WO3 (N2 stream, 800 °C for 2 h and 820 °C for 4 h).

A new straightforward methodology to overcome limitations of the Passerini reaction is developed affording alkoxyamide derivatives (IV).

The catalytic properties of niobia and alumina supported platinum and platinum-tin catalysts were evaluated at the conversion of n-heptane at 773K. Over a niobia supported platinum catalyst the reaction proceeded via a monofunctional path, with a high selectiviy for oleflns. This was explained by the formation of a SMSI state, leading to the coverage of platinum particles by NbO x and the formation of metal-support interfacial sites. The presence of tin inhibited the formation of a SMSI state, causing a decrease in the olefins/toluene ratio.

Alumina and niobia Pt-Sn supported bimetallic catalysts were characterized by TPR, hydrogen chemisorption and cyclohexane dehydrogenation. The TPR profiles of niobia supported Pt-Sn catalysts showed the presence of different precursors from the ones obtained on alumina. Furthermore, the hydrogen uptakes indicated that the amount of metallic tin formed in the niobia supported catalysts was higher than in the alumina supported catalysts. After reduction at 773 K, the platinum/niobia catalyst displayed a strong metal-support interaction (SMSI) effect, with the creation of new interfacial active sites. The addition of a small tin content led to a suppression of the SMSI. Increasing the amount of tin, however, induced a marked poisoning of the platinum.

An efficient and practical method for the preparation of alpha-imidazol-1-yl esters from 1,2-diaza-1,3-dienes (DDs), alpha-amino esters, and aldehydes is described. The overall sequence features a Michael-type conjugate addition between the alpha-amino ester and the DD, followed by iminium ion formation via condensation with the aldehyde and 1,5-electrocyclization of the resulting thermally generated azavinyl azomethine ylide to afford eventually alpha-imidazol-1-yl esters. Such a protocol allows access to enantiomerically pure imidazoles from optically pure alpha-amino esters.

SrVO2H, Sr2VO3H, and Sr3V2O5H2 are prepared by topochemical replacement of oxide ions in SrVO3, Sr2VO4, and Sr3V2O7, resp., by hydride ions using CaH2 (600—630 °C).

We describe herein an approach to the total synthesis of functionalized pyrrolizidinones and pyrrolizidines. The synthetic sequence is based on a highly stereoselective substrate-controlled Morita–Baylis–Hillman (MBH) reaction between a chiral amino-aldehyde and methyl acrylate. The selectivity attained in this reaction was controlled by the presence of a hydroxyl group adequately placed in the structure of the amino-aldehyde used as the nucleophilic component of the MBH reaction. The MBH adducts were used as substrate for an efficient total synthesis of pyrrolizidinones and pyrrolizidines in good overall yield.

Progress in the theoretical understanding of catalysis by size-selected subnanometer (or ultranano) metal clusters deposited onto an oxide surface is reviewed. Attention is focused on a few simple general concepts that can help orienting oneself in this rapidly developing but already extensive field: (i) the fluxional character of ultrananoclusters and the associated need for systematically sampling the system's potential energy surface; (ii) the influence of the underlying support (including possible defects) in terms of epitaxial relationships, generated electrostatic field and electronic interactions, and the possible active role of the support in the reaction mechanisms; (iii) the evolution of ligand adsorption energetics, structure and dynamics as a function of coverage, including many-body and synergic interactions among ligands, and the formation of catalytically active species; (iv) the robustness of the catalyst in terms of surface diffusion and cluster disaggregation. The possibility of out-of-equilibrium effects and the theoretical methodology required for their predictive description are also briefly mentioned. These concepts are illustrated via selected examples drawn from our own recent work.

All synthesized compounds are screened for their in vitro activity against Plasmodium falciparum (W2) and cytotoxicity to Hep G2A16 cells.

A tunable microwave-assisted protocol for the synthesis of two biologically relevant families of heterocycles has been designed. Via a simple switch of reaction conditions, the same starting materials can be engaged in either an improved synthesis of the dihydrotriazine scaffold or a novel, first-in-class MCR to render the challenging 5-aminoimidazole nucleus in a single step. An additional first-in-class MCR is also reported utilizing guanidines to afford 2,5-aminoimidazoles.

A very general and robust multicomponent-reaction protocol involving an Ugi condensation between ethyl glyoxylate, isonitriles, N -Boc-α-amino acids, and mono - N -Boc-protected diamines followed by a series of acid-promoted cyclization steps in a one-pot fashion is reported. This process allows for the assembly of complex polycyclic structures by means of just two simple synthetic operations and a single chromatographic purification in high overall yields. Of note, the first scaffolds derived from a highly ­selective sequence of ring-closing events involving three internal amino nucleophiles is reported.