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A novel visible-light-promoted copper-catalysed process for the Csp–Csp cross-coupling reaction of terminal alkynes at room temperature is described. The current photochemical method is simple, highly functional group compatible, and more viable towards the construction of bio-active 1,3-unsymmetrical conjugated diynes without the need of bases/ligands, additives and expensive palladium/gold catalysts.

Copper-catalyzed ring-opening reactions of cyclic 1,2-sulfamidates with a wide range of Grignard reagents have been investigated. The use of lithium chloride as an additive is essential to activate CO bond cleavage. The reaction represents highly regio- and stereoselective, and thus allows for efficient synthesis of enantioenriched α-branched benzylamine derivatives. Furthermore, we demonstrated that the products are potential to be used as building blocks for the preparation of wide range of nitrogen-containing heterocycles.

Biomass and biomass-derived carbohydrates have a high extent of functionality, unlike petroleum, which has limited functionality. In biorefinery applications, the development of methods to control the extent of functionality in final products intended for use as fuels and chemicals is a challenge. In the chemical industry, heterogeneous catalysis is an important tool for the defunctionalization of functionalized feedstocks and biomass-derived platform chemicals to produce value-added chemicals. Herein, we review the recent progress in this field, mainly of vapor phase chemical conversion of biomass-derived C4 -C6 carboxylic acids and esters using copper-silica nanocomposite catalysts. We also demonstrate that these nanocomposite catalysts very efficiently convert biomass-derived platform chemicals into cyclic compounds, such as lactones and hydrofurans, with high selectivities and yields.

The process is found to form the desired carboxylic acids with complete (E) selectivity except for substrate (XV), where an E/Z mixture is identified.

Four new steroids, klyflaccisteroids G—J, are isolated and evaluated for their biological activity.

Bioactivity-guided fractionation of the MeOH extract from the roots of Euphorbia kansui resulted in the isolation of two new jatrophane-type diterpenoids, kanesulones A (1) and B (2), together with six known jatrophane-type diterpenoids (3-8) and ten known ingenane-type diterpenoids (9-18). Their chemical structures were elucidated on the basis of spectroscopic data interpretation, especially 1D and 2D NMR such as HMQC, HMBC, COSY and NOESY, and HRESIMS data as well as CD analysis. Compounds 1-8 and 11-18 exhibited the inhibitory effects on LPS-induced nitric oxide production with IC50 values ranging from 0.7 to 46.5μM in RAW 264.7 macrophages.

Yellow-emitting nanorod phosphors Ba2-2xMg(PO4)2:Eu2x2+ (x = 0.01—0.09) are precipitated from stoichiometric aqueous solutions of Ba(NO3)2, Mg(NO3)2, (NH4)2HPO4, and Eu2O3 (pH 7—11 adjusted with NaOH, 90 °C, 6 h) followed by annealing (5%H2/N2, 600—800 °C, 2 h).

The preparation of the catalysts is described as well as their highly effective use in the title reaction of aryl or alkyldithiomalonates with β-aryl or alkyl substituted nitroolefins.

An efficient method for isocyanate formation from N-Boc carbamates was developed utilizing a Hendrickson “POP” reagent as a dehydrating agent. By using this reagent, isocyanates were formed preferentially from N-Boc carbamates over other carbamates. The reaction could be paired with successive reactions such as Friedel–Crafts-type cyclization and urea formation.

Chiral oxazaborolidinium ion-catalyzed asymmetric cyclopropanation of α- or α,β-substituted acroleins with α-alkyl-α-diazoesters has been developed. With this methodology, chiral functionalized cyclopropanes containing a quaternary stereogenic center were obtained with high to excellent enantioselectivities (up to >99% ee). The synthetic utility of optically enriched functionalized cyclopropane was demonstrated in the first total synthesis of (+)-hamavellone B, which establishes the absolute configuration of natural (+)-hamavellone B.

Described herein is the development of practical routes to 8-aminoquinolines by using readily installable and easily deprotectable amidating reagents. Two scalable procedures were optimized under Rh(III) -catalyzed conditions: i) the use of pre-generated chlorocarbamates and ii) a two-step one-pot process that directly employs carbamates. Both approaches are highly convenient for the gram-scale synthesis of 8-aminoquinolines under mild conditions. Facile deprotection of the synthetically versatile amidating groups was achieved under the Pd-catalyzed transfer hydrogenation conditions with simultaneous deoxygenation of quinoline N-oxides, thus yielding 8-aminoquinolines in excellent overall efficiency.

The first successful example of a visible-light-induced copper-catalyzed process for C-H annulation of arylamines with terminal alkynes and benzoquinone is described. This three-component reaction allows use of a variety of commercial terminal alkynes as coupling partners for the one-step regioselective synthesis of functionalized indoles. Moreover, the current process represents a sustainable and atom-economical approach for the preparation of complex indoles from easily accessible starting materials under visible-light irradiation, without the need for expensive metals and harsh reaction conditions.

An efficient method for copper nanoparticle catalyzed ligand-free S–Csp bond formation was developed by using dimethyl sulfoxide as the solvent, a base, and molecular oxygen as a green oxidant. This study provides a new catalytic route for the production of alkynyl sulfides through dual activation of S–S and C–H bonds. A wide range of alkynyl sulfides were synthesized on a large scale with a low catalyst loading (0.5 mol% Cu). This synthetic methodology could also be extended to selenides, whereas tellurides underwent analogous reactions in the absence of a catalyst.

A convenient one-pot procedure to synthesize a variety of highly optically active syn-α-aryl-β-hydroxy Weinreb amides using an asymmetric Roskamp/reduction strategy is described. An oxazaborolidinium ion catalyzed asymmetric Roskamp reaction of α-aryl diazo Weinreb amides with aldehydes produced α-phenyl-β-keto Weinreb amides, which were in situ reduced with zinc borohydride to give syn-α-aryl-β-hydroxy Weinreb amides in good yields (up to 87%) with high enantioselectivities (up to 99% ee) and syn stereoselectivities (>20:1).

A novel, catalytic enantioselective route to synthesize a variety of α-tertiary aryl ketones via a boron Lewis acid promoted formal insertion of aryldiazoalkane into the C–H bond of both aromatic and aliphatic aldehydes is described. In the presence of chiral (S)-oxazaborolidinium ion catalyst 1, the reaction proceeded in good yields (up to 94%) with excellent enantioselectivities (up to 99% ee).

Two new biflavones, (aR)-3′-methoxycupressuflavone (1) and (aR)-3′,3′′′-dimethoxycupressuflavone (2), and two new furanone glucosides, zabeliosides A and B (3 and 4, resp.), along with two known biflavones, cupressuflavone (5) and amentoflavone (6), were isolated from the leaves of Zabelia tyaihyonii. The structures of the new compounds were elucidated by 1D- and 2D-NMR, HR-ESI-MS, and circular dichroism.

Two new pregnane glycosides, hirsutosterosides A and B (1 and 2), as well as two new α-tocopherylhydroquinone glycosides, cladophenol glycosides A and B (3 and 4) were isolated from a soft coral Cladiella hirsuta. In addition, a new steroidal glycoside, lobatasteroside A (5) along with six known steroids (6–11), were discovered from the other soft coral Sinularia nanolobata. Their structures were elucidated by extensive spectroscopic analysis. Cytotoxicities of the isolates against a limited panel of cancer cell lines were reported. The inhibitory activities for superoxide anion generation and elastase release for these compounds were also examined to evaluate the anti-inflammatory potential.

Investigation of a suitable access to the cyclization precursors (III) and (VII) shows that EDC·HCl is an optimal agent which allows the isolation of the pure products by simple filtration.

A new “single-flask” method was developed for the synthesis of imidazolidines and pyrrolidines with high stereoselectivity. First, a Schiff base was arylated with an aryne. Second, an intramolecular proton transfer took place from the methylene position to the anionic aryne ring. Third, the resultant ylide reacted with a second equivalent of the same Schiff base in situ or an electron-deficient alkene through a (3+2) cycloaddition. These sequential tandem 1,2-addition/(3+2) cycloaddition reactions led to the desired heterocycles in 63–88 % yields.

The new benzylated and prenylated flavone, cudracuspiflavanone A (I) is isolated from the title species along with sixteen known chromenes and flavonoids.

A highly efficient and regioselective halogenation reaction of unsymmetrical pyridine N-oxide under mild conditions is described. The methodology provides a practical access to various 2-halo-substituted pyridines, which are pharmaceutically important intermediates.

Metal dodecaborates M_2/_nB_(12)H_(12) (n denotes the valence of the metal M), containing icosahedral polyatomic anion [B_(12)H_(12)]^(2−), have been attracting increasing interest as potential energy materials, especially in the context of hydrogen storage and superionic conductivity. M_2/_nB_(12)H_(12) are commonly formed as dehydrogenation intermediates from metal borohydrides M(BH_4)_n, like LiBH_4 and Mg(BH_4)_2, which are well-known as potential high-density hydrogen storage materials. The strong B−B bond in the icosahedral [B_(12)H_(12)]^(2−), however, is regarded to be the key factor that prevents the rehydrogenation of dodecaborates. In order to elucidate the mechanism as well as to provide effective solutions to this problem, a novel solvent-free synthesis route of anhydrous M_2/nB_(12)H_(12) (here M means Li, Na, and K) has been developed. Thermal stability and transformations of the anhydrous single phase Li_2B_(12)H_(12) suggested the formation of the high temperature polymorph of Li_2B_(12)H_(12) during the dehydrogenation of LiBH_4, while concurrently emphasized the importance of further investigation on the decomposition mechanism of metal borohydrides and metal dodecaborates. The high stability of icosahedral [B_(12)H_(12)]^(2−), on the other hand, favors its potential application as solid electrolyte. Recently, Na^+ conductivity of Na_2B_(12)H_(12) was reported to be 0.1 S/cm above its order−disorder phase transition at ∼529 K, which is comparable to that of a polycrystalline β”-Al_2O_3 (0.24 S/cm at 573 K) solid state Na-electrolyte. Mechanistic understanding on the diffusion behavior of cation and further improvement of ionic conductivity at a lower temperature, however, are important in order to facilitate the practical application of metal dodecaborates as superionic conductors.

ConspectusOver the past decades, numerous efforts have been devoted to synthesizing nanostructured materials with specific morphology because their size and shape play an important role in determining their functions. Self-assembly using weak and reversible interactions or bonds has provided synthetic routes toward various nanostructures because it allows a “self-checking” and “self-error-correcting” process under thermodynamic control. By contrast, the use of irreversible covalent bonds, despite the potential to generate more robust structures, has been disfavored in the synthesis of well-defined nanomaterials largely due to the lack of such self-error-correcting mechanisms. To date, the use of irreversible bonds is largely limited to covalent fixation of preorganized building blocks on a template, which, though capable of producing shape-persistent and robust nanostructured materials, often requires a laborious and time-consuming multistep processes. Constructing well-defined nanostructures by self-asse...

The activity-guided fractionation of the MeOH extract of the flower of Paulownia coreana led to the isolation of a new geranylated flavanone, 3'-O-methyl-5'-hydroxydiplacol (1), along with 10 known compounds (2-11). Their structures were determined using spectroscopic techniques, which included one and two dimensional (1- and 2D)-NMR. Among the isolates, compounds 1-6 showed potent inhibitory activities against lipopolysaccharide (LPS)-induced nitric oxide production with IC50 values ranging 1.48 to 16.66 µM.

Palladium-catalyzed aminocarbonylation for the synthesis of alkynyl amides from the coupling reactions of alkynyl carboxylic acids, amines, and carbon monoxide is reported.

Highly enantioselective 1,3-dipolar cycloaddition reactions of α-substituted diazoacetates are accomplished by catalysis of the chiral oxazaborolidinium ion. Functionalized 2-pyrazolines are synthesized in high to excellent enantiomeric ratios (up to >99 : 1). The synthetic utility of 2-pyrazoline was expanded via preparation of 2,4-diamino ester compounds bearing a chiral quaternary carbon center.

Five new pyrrole alkaloids, morrole B and C (Ia) and (Ib), resp., morrole E (II), morrole G (III), and morrole H (IV), are isolated along with 12 known pyrrole alkaloids from the fruits of Morus alba.

The reaction fails with alkyl and alkenyl boronic acids, such as isopropyl or (E)-styryl boronic acid.

The Rh-catalyzed alkylation of a variety of substituted quinoline N-oxides with activated methylene compounds (II) and (VI) is investigated to give C-8 substituted products selectively.

Reported herein is the metal-catalyzed regioselective C–H functionalization of quinoline N-oxides at the 8-position: direct iodination and amidation were developed using rhodium and iridium catalytic systems, respectively. Mechanistic study of the amidation revealed that the unique regioselectivity is achieved through the smooth formation of N-oxide-chelated iridacycle and that an acid additive plays a key role in the rate-determining protodemetalation step. While this approach of remote C–H activation using N-oxide as a directing group could readily be applied to a wide range of heterocyclic substrates under mild conditions with high functional group tolerance, an efficient synthesis of zinquin ester (a fluorescent zinc indicator) was demonstrated.

A phytochemical investigation of the fruits of Melia azedarach led to the isolation of two new C-seco-nimbolinin-type limonoids, 3α-acetoxy-1α,7α-dihydroxy-12α-methoxynimbolinin (1) and 3α-acetoxy-1α,12α-dihydroxy-7α-(2-methylprop-2-enoyl)nimbolinin (2), together with eleven known compounds, 3–13. Their structures were elucidated on the basis of extensive spectroscopic analysis, including 1H- and 13C-NMR, HMQC, HMBC, NOESY, and HR-FAB-MS.

Copper bromide was found to be an efficient catalyst for a domino reaction sequence leading to 3-pyrrolines. The Cu(I)-catalyzed Crabbe reaction of propargyl sulfonamide and selective cycloisomerization of the allene intermediate were carried out using microwave irradiation conditions affording a wide range of 2-substituted- and 2,5-disubstituted-3-pyrrolines. Mechanistic studies of the reaction intermediates revealed two possible reaction pathways; both invoke the importance of vinyl copper intermediates.

Highly hindered β-amino 1,2,3-triazole derivatives bearing a gem-diaryl group are obtained by copper (I)-catalyzed Huisgen cycloaddition of terminal alkynes with unmasked azidoamines derived from amino acids.

isolation, structure determination, and inhibitory effects of the new noreudesmane-type sesquiterpenoid 4-methoxy-oxyphyllenone A (I) and fifteen known compounds on NO production in LPS-induced RAW 264.7 cells

E-mail: soypark23@dankook.ac.krReceived January 17, 2014, Accepted March 10, 2014Key Words : Buddleja officinalis , Acetogenic glycoside, Hydrolysis, NMRBuddleja officinalis Maximowicz, which belongs to theBuddlejaceae, is a shrub tree and widely distributed in Asia,Africa, and America. It has been regarded as a traditionalherbal medicine for the treatment of inflammation, con-junctivitis, headache, and clustered nebulae.

Benzil derivatives such as diaryl 1,2-diketones are synthesized via the direct decarboxylative coupling reaction of aryl propiolic acids and their oxidation. The optimized conditions are that the reaction of aryl propiolic acids and aryl iodides is conducted at 140 °C for 6 h in the presence of 10 mol % CuI/Cu(OTf)2 and Cs2CO3, after which HI (aq) is added and further reacted. The method shows good functional group tolerance toward ester, aldehyde, cyano, and nitro groups. In addition, symmetrical diaryl 1,2-diketones are obtained from aryl iodides and propiolic acid in the presence of palladium and copper catalysts.

A regioselective synthesis of trialkylpyrazines via nickel-catalyzed cross-coupling reaction of pyrazine triflate is reported. The 5-substituted 2,3-dimethylpyrazine derivatives including trail pheromone components of the ant Eutetramorium mocquerysi have been successfully synthesized in good yields by nickel-catalyzed Negishi cross-coupling reactions of pyrazine triflate mediated by alkyl and arylzinc halides.

Cu2SnSe3 nanoparticles are sonochemically synthesized under multibubble sonoluminescence conditions from mixtures of CuCl, SnCl2, and Se dissolved in a mixture of ethanolamine and ethylene glycol (ultrasound, 25 °C, 20 min, 78% yield).

A trifluoroethylation of alkynes through a palladium-catalyzed decarboxylative coupling reaction was developed. When alkynyl carboxylic acids and ICH2CF3 were allowed to react with [Pd(η3-allyl)Cl]2/XantPhos and Cs2CO3 in N,N-dimethylformamide (DMF) at 80 °C for 1 h, the desired products were formed in good yields. This catalytic system showed high functional group tolerance.

The mixed-valent vanadosilicate K4.6{(VIVO)0.8 (VVO)1.2H2O}2 {Si12O32 [Cs(H2O)4]}·xH2O is obtained by partial oxidation of Na7{(VIVO)2H2O}2 {Si12O32 [Cs(H2O)4]}·xH2O with Br2 in an organic solvent (not specified) followed by cation exchange using a KCl solution (80 °C, 6 h).