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The symmetry breaking instability in the irreversible Oregonator model for sufficiently low and unequal diffusion coefficients of its three intermediate species has been investigated using the rate constants of Field and Försterling. The effects of diffusion and the control parameters on the shift of Hopf bifurcation points associated with the emergence of heterogeneous waves of short wavelengths are reported. The results are found to be in good agreement with those obtained by Prigogine et al. for Brusselator and Turing models. [ABSTRACT FROM AUTHOR]

Friedman’s differential isoconversional approach is applied to obtain effective activation energy ( E α ) for Poly (butylene terephthalate) and PBT/15AMMT nanocomposites. The presence of 15AMMT content has largely affected E α values. Further Vyazovkin and Sbirrazzuoli’s approach is used to determine Hoffman-Lauritzen parameters ( K g & U* ). The crystallization regime transition (II–III) occurs for neat PBT at 189 °C and its nanocomposites is at 189–192 °C.  K g(III) /K g(II) ratios are closer to theoretical value of 2. However the corresponding value of U* is inappropriately too low with negative sign (Correlation coefficient R 2  = 0.9–0.99) and which is however highly anomalous when compared to other polymers. Setting U* to 6300 J/mol, 4300 J/mol and 0 J/mol, resulted in poor K g(III) /K g(II) ratios and R 2 . This imply that there is a considerable chain mobility during regime II crystallization which is explained in terms of rapid extraction of PBT chain segments by the force of crystallization, following the tube-reptation postulate. [ABSTRACT FROM AUTHOR]

Anisomycin shows potent biological activity and it has attracted much attention since its isolation in 1954, with around 13 total syntheses and 20 formal syntheses, and also two reports concerning analogues of anisomycin, reported to date. The present review highlights all of these synthetic approaches (around 35) to the total or formal synthesis of anisomycin along with its isomers and analogues. 1 Introduction 2 Isolation and Therapeutic Importance 3 Total Synthesis of (+)-, (-)-, and (±)-Anisomycins and Their Analogues 4 Formal Synthesis of (+)- and (-)-Anisomycins and Their Analogues 5 Conclusion. [ABSTRACT FROM AUTHOR]

Enantioselective syntheses of tert -butyl (( S )-2-(3,5-difluorophenyl)-1-(( S )-oxiran-2-yl)ethyl)carbamate and (( S )-2-(3,5-difluorophenyl)-1-(( R )-oxiran-2-yl)ethyl)carbamate are described. We utilized asymmetric syn- and anti- aldol reactions to set both stereogenic centers. We investigated ester-derived Ti-enolate aldol reactions as well as Evans’ diastereoselective syn -aldol reaction for these syntheses. We have converted optically active (( S )-2-(3,5-difluorophenyl)-1-(( S )-oxiran-2-yl)ethyl)carbamate to a potent β-secretase inhibitor. [ABSTRACT FROM AUTHOR]

Enantioselective syntheses of (-)-alloyohimbane and (-)-yohimbane were accomplished in a convergent manner. The key step involves a modified mild protocol for the enantioselective enzymatic desymmetrization of a meso-diacetate. This provides convenient access to an optically active monoacetate in multi-gram quantities and in high enantiomeric purity. This monoacetate was converted to (-)-alloyohimbane. Reductive amination of the derived aldehyde caused isomerization to the trans-product and, ultimately, the formation of (-)-yohimbane. [ABSTRACT FROM AUTHOR]

Protecting-group-free synthesis of hydroxylated styryl-cinnamate hybrids (C6-C2-C6-C3 unit), inspired by the natural product salvianolic acid F, was achieved by a step-economical route involving sequential double C-C bond formation in one pot. The method involved multiple reactions (Perkin condensation/decarboxylation-Heck cross-coupling reactions) by using simple precursors (i.e., hydroxylated benzaldehyde, arylacetic acid, and acrylic acid derivatives) in one pot and yielded the desired unnatural small hybrid molecules in varying yields of 35-65 % with E selectivity under microwave irradiation, whereas the reported conventional route for the synthesis of salvianolic acid F itself requires six steps with an overall yield of 10.0 % in addition to tedious separation of E/Z isomers that arise from a Wittig reaction. Apart from an economical synthesis and product diversity, we herein report the potential of some hybrid molecules with the catechol core to selectively inhibit glioma cells. The intrinsic mode of action of our lead molecule, involving caspase 6 and the quinonemethide pathway, is also reported on the basis of 1H NMR spectroscopy guided metabolomic profiling. We emphatically demonstrate the role of our hybrid molecules, analogues of salvianolic acid F, in forcing glioma cells towards apoptosis by specifically perturbing the concentration of glutathione along with that of caspase 6. [ABSTRACT FROM AUTHOR]

The study was conducted to evaluate the suitability of using buffalo head and heart meat in emulsion based products preparation and to assess their quality during refrigerated storage. The whole study was carried out in three phases. In phase I, head meat patties (HMP) (treatment I, II and III) were prepared in which head meat was substituted with 15%, 20% and 25% skeletal meat and compared with patties from skeletal meat (control). Treated patties had higher emulsion stability, cooking yield, pH and lower shrink percentage and chewiness than control. Sensory attributes of control and treated patties did not differ significantly. In phase II, HMP were prepared in which head meat was substituted with 20%, 30% and 40% heart meat and similarly compared with control as in phase I. Addition of heart meat in HMP had significantly ( P < 0.05) increased pH, cooking yield, moisture, lower protein and fat content than control patties. Hardness, gumminess and chewiness values of control patties were higher than treated patties. HMP with heart meat had higher tenderness than control. Control patties rated better than treated patties during sensory evaluation. In phase III, quality of patties was assessed at refrigerated storage (4 ± 1 °C) for 15 days. The patties remained stable with minor changes in physico-chemical, microbiological and sensory quality during refrigerated storage for 15 days. Buffalo head and heart meat effectively be utilised in developing patties. [ABSTRACT FROM AUTHOR]

Substituted oxocene derivatives have been synthesized by Lewis acid catalyzed reactions of ε-hydroxyalkene and substituted aromatic aldehydes. The Cu(OTf)2-bis-phosphine catalyzed reaction typically provides substituted dihydropyran derivatives through an olefin migration followed by a Prins cyclization. The corresponding reaction catalyzed by TMSOTf or BF3·OEt2 provided eight-membered cyclic ethers (oxocenes), selectively. This methodology provides convenient access to a variety of 2,4,8-trisubstituted oxocenes in good yields and excellent diastereoselectivities. [ABSTRACT FROM AUTHOR]

ABSTRACT A new 'grafting from' strategy for grafting of different monomers (methacrylates, acrylates, and acrylamide) on poly(vinylidene fluoride) (PVDF) backbone is designed using atom transfer radical coupling (ATRC) and atom transfer radical polymerization (ATRP). 4-Hydroxy TEMPO moieties are anchored on PVDF backbone by ATRC followed by attachment of ATRP initiating sites chosen according to the reactivity of different monomers. High graft conversion is achieved and grafting of poly(methyl methacrylate) (PMMA) exhibits high degree of polymerization (DPn = 770) with a very low graft density (0.18 per hundred VDF units) which has been increased to 0.44 by regenerating the active catalyst with the addition of Cu(0). A significant impact on thermal and stress-strain property of graft copolymers on the graft density and graft length is noted. Higher tensile strain and toughness are observed for PVDF- g-PMMA produced from model initiator but graft copolymer from pure PVDF exhibits higher tensile strength and Young's modulus. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 995-1008 [ABSTRACT FROM AUTHOR]

Reactions of the lightly stabilized triosmium cluster [Os3(CO)8{μ3-Ph2PCH2P(Ph)C6H4}(μ-H)] with tri(2-thienyl)phosphine (PTh3) and tri(2-furyl)phosphine (PFu3) are described and compared to analogous reactions with PPh3. At room temperature, a number of products are isolated: [Os3(CO)10(μ-dppm)] from CO addition, [Os3(CO)8(PR3){μ3-Ph2PCH2P(Ph)C6H4}(μ-H)] from phosphine addition, [Os3(CO)9(PR3)(μ-dppm)] from phosphine and CO addition and [Os3(CO)8(PR3)2(μ-dppm)] from addition of two equivalents of phosphine. The latter are shown by NMR and X-ray diffraction to exist as 1,2-isomers, whereby one phosphine is bound to the non-dppm-substituted center and the second shares an osmium atom with one end of the diphosphine. Heating 1,2-[Os3(CO)8(PTh3)2(μ-dppm)] at 100 °C results in its clean isomerization to the 1,1-isomer in which both monodentate phosphines are located on the same osmium atom. Prolonged heating of [Os3(CO)8(PR3)2(μ-dppm)] (R = Th, Ph) at 110 °C gives [Os3(CO)9(PR3)(μ-dppm)] and the new lightly stabilized clusters [Os3(CO)7(PR3){μ3-Ph2PCH2P(Ph)C6H4}(μ-H)], the latter being formed by loss of phosphine and CO with concurrent metalation of a phenyl ring. Heating [Os3(CO)8(PFu3)2(μ-dppm)] at 110 °C gives [Os3(CO)9(PFu3)(μ-dppm)] together with the carbon-phosphorus bond cleavage products [Os3(CO)7(μ-PFu2)(μ3-η2-C4H2O)(μ-H)(μ-dppm)] and [Os3(CO)7(μ-PFu2)(μ3-η2-C6H3CH3)(μ-H)(μ-dppm)]. All new compounds were characterized by analytical and spectroscopic techniques together with single crystal X-ray diffraction analysis of nine clusters. Density functional theory (DFT) calculations have been carried out on isomers of [Os3(CO)8(PR3)2(μ-dppm)] in order to understand the observed isomer ratios. [ABSTRACT FROM AUTHOR]

Background Dengue fever virus transmitted by Aedes aegypti causes lethal mortalities of human beings, and, because of the lack of any vaccine, management of this vector, especially with phytochemicals, is essential. In the present investigation, the structure-activity relationship of monoterpenes and their acetyl derivatives was studied to identify structural features that are responsible for mosquitocidal activity. Results Derivatization of monoterpenes (eugenol, geraniol, linalool, L-menthol and terpeniole) followed by structure-activity relationship studies identified all five acetyl derivatives as having enhanced mosquitocidal activity against fourth-instar larvae of Aedes aegypti. Acetylation of the hydroxyl group in general increased activity in comparison with hydroxyl compounds. Based on LC50 values (ppm), the activities could be placed in the following order: eugenyl acetate (50.2) > linalyl acetate (119.7) > terpinyl acetate (287.1) > menthyl acetate (308.4) > geranyl acetate (325.5), as compared with monoterpenoids: eugenol (82.8) > linalool (242.6) > terpineol (331.7) > L-menthol (365.8) > geraniol (415.0). In eugenyl acetate, the presence of an aromatic ring and a side chain with an allylic double bond makes it most effective. Conclusion Bioactive functional groups identified in the study may contribute to the understanding of larvicidal activity of acetyl derivatives and may help in the development of ecofriendly mosquito larvicidal compounds. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Abstract: Organocatalytic reactions of 3-olefinic oxindoles and pentane-1,5-dial were investigated to provide access to substituted spirocyclohexane oxindoles via Michael/aldol cascade reactions. Of particular interest, we have examined the stereochemical outcome of electron withdrawing and electron-donating groups on the oxindole ring nitrogen. Interestingly, we have observed that the N-protecting group on the oxindole has critical effect on aldol ring closure leading to ultimate stereochemical outcome of the hydroxyl center. The overall process is quite efficient and afforded products with multiple stereocenters in high yields and excellent enantioselectivities (>99% ee). [Copyright &y& Elsevier]

An enantioselective and convergent total synthesis of pladienolide B (1) is described. Pladienolide B binds to the SF3b complex of a spliceosome and inhibits mRNA splicing activity. The synthesis features an epoxide opening reaction, an asymmetric reduction of a β-keto ester, and a cross metathesis strategy for the side chain synthesis. [ABSTRACT FROM AUTHOR]

Abstract: Solid supported palladium(0) (SS-Pd) catalyzed highly chemoselective reduction of nitroarenes to the corresponding anilines was accomplished under a milder reaction condition. This catalyst showed high compatibility with various reducing agents (NaBH4, Et3SiH, and NH2NH2·H2O) and a large number of reducible functional groups such as sulfonamide, amides, carboxylic acid, ester, alcohol, halide, hetero cycle, nitrile, alkene, carbonyl, O-benzyl, and N-benzyl were tolerated. Most of the reactions were clean and high yielding. The SS-Pd catalyst could be recycled up to seven runs without significant loss of activity. [Copyright &y& Elsevier]

A long-existing problem of cyclohexane-1,3-dione derivatives (CDD) synthesis from unreactive acetone through consecutive Michael-Claisen process was solved under this study. The practical applicability of this process was tested for a novel compound ethyl 3-(2,4-dioxocyclohexyl)propanoate for up to 20-gram scale. Furthermore, the scope of different acetone derivatives was investigated and resulted with similar consecutive Michael-Claisen process for CDD synthesis. The reaction exhibited remarkable regioselectivity in Michael addition followed by Claisen cyclization. In this process high substrate selectivity was observed for CDD synthesis following consecutive double-Michael-Claisen and Michael-Claisen cyclization. [ABSTRACT FROM AUTHOR]

Stereoselective syntheses of both functionalized tetrahydropyran subunits of (--)-lasonolide. A are described. These tetrahydropyran rings were constructed using catalytic asymmetric hetero Diels--Alder reactions as the key steps. The C22 quaternary stereocenter present in the upper tetrahydropyran ring was constructed by a stereoselective alkylation, and the C9 hydroxy stereochemistry of the bottom tetrahydropyran was constructed by a stereoselective epoxidation followed by a regioselective epoxide opening reaction. [ABSTRACT FROM AUTHOR]

In this study, we have investigated the role of a glioma-specific cation channel assembled from subunits of the Deg/epithelial sodium channel (ENaC) superfamily, in the regulation of migration and cell cycle progression in glioma cells. Channel inhibition by psalmotoxin-1 (PcTX-1) significantly inhibited migration and proliferation of D54-MG glioma cells. Both PcTX-1 and benzamil, an amiloride analog, caused cell cycle arrest of D54-MG cells inG0/G1 phases (by 30 and 40%, respectively) and reduced cell accumulation in S and G2/M phases after 24 h of incubation. Both PcTX-1 and benzamil up-regulated expression of cyclin-dependent kinase inhibitor proteins p21Cip1 and p27Kip1. Similar results were obtained in U87MG and primary glioblastoma multiforme cells maintained in primary culture and following knockdown of one of the component subunits, ASIC1. In contrast, knocking down δENaC, which is not a component of the glioma cation channel complex, had no effect on cyclin-dependent kinase inhibitor expression. Phosphorylation of ERK1/2 was also inhibited by PcTX-1, benzamil, and knockdown of ASIC1 but not δENaC in D54MG cells. Our data suggest that a specific cation conductance composed of acid-sensing ion channels and ENaC subunits regulates migration and cell cycle progression in gliomas. [ABSTRACT FROM AUTHOR]

Enantioselective total syntheses of the proposed structures of macrolide cytotoxic agents iriomoteolide-1a and -1b have been accomplished. The synthesis was carried out in a convergent and stereoselective manner. However, the present work suggests that the reported structures have been assigned incorrectly. The synthesis features Julia−Kocienski olefination, Sharpless asymmetric epoxidation, Brown asymmetric crotylboration, a Sakurai reaction, an aldol reaction, and enzymatic resolution as the key steps. [ABSTRACT FROM AUTHOR]

The reaction of the five-membered C,N-palladacycle [(L)PdCl]2, where LH= 1-methyl-5-phenyl- 1H-1,4-benzodiazepin-2(3H)-one, with 1,2-ethanebis(diphenylphosphine), dppe, leads to the formation of the bridged palladacycle. [Pd2L2(μ-dppe)Cl2] 3, which was characterised in solution by 1H and 31P NMR spectroscopy and in the solid state by X-ray crystallography. Complex 3 was tested in vitro against a number of cell lines. For example, it inhibited K562 leukaemia cells with an IC50value of 4.3 μM (1 h exposure) and displayed cathepsin B inhibitory action with an IC50 value of 3 μM. [ABSTRACT FROM AUTHOR]

The reaction of the five-membered C,N-palladacycle [(L)PdCl]2, where LH = 1-methyl-5-phenyl-1H-1,4-benzodiazepin-2(3H)-one, with 1,2-ethanebis(diphenylphosphine), dppe, leads to the formation of the bridged palladacycle. [Pd2L2(μ-dppe)Cl2] 3, which was characterised in solution by 1H and 31P NMR spectroscopy and in the solid state by X-ray crystallography. Complex 3was tested in vitroagainst a number of cell lines. For example, it inhibited K562 leukaemia cells with an IC50value of 4.3 μM (1 h exposure) and displayed cathepsin B inhibitory action with an IC50value of 3 μM. [ABSTRACT FROM AUTHOR]

The total synthesis of the proposed structure of anticancer agent stereocalpin A is described. The synthesis features a diastereoselective synthesis of a 5-hydroxy-2,4-dimethyl-3-oxooctanoic acid unit with asymmetric anti- and syn-aldol reactions as the key steps. Initial cycloamidation led to complete epimerization at the C-11 stereocenter due to unique steric constraints in the 12-membered depsipeptide ring. A late-stage methylation strategy led to the synthesis of the proposed structure of stereocalpin A. [ABSTRACT FROM AUTHOR]

Abstract: Heating the electron-deficient [Os3(CO)8(μ-H)(μ3-Ph2PCH2P(Ph)C6H4)] (1) and Ph3GeSPh in benzene at 80°C led to the thiolato bridged compounds, [Os3(CO)8(μ-H)(μ-SPh)(μ-dppm)] (2) and [Os3(CO)7(μ-H)(μ-SPh)(μ3-SC6H4)(μ-dppm)] (3), formed by cleavage of Ge–S and C–S bonds of the ligand, in 40% and 17% yields, respectively. Both compounds 2 and 3 have been characterized by a combination of elemental analysis, infrared and 1H NMR spectroscopic data together with single crystal X-ray crystallography. Compound 3 contains an open triangle of osmium atoms bridged by a SPh and SC6H4 ligands on opposite sides of the cluster with a dppm ligand bridging one of the Os–Os edges. Compound 2 consists of a closed triangular cluster of osmium atoms with a bridging SPh, and a bridging hydride ligand on the same Os–Os edge, and a dppm ligand bridging one of the remaining Os–Os edges. [Copyright &y& Elsevier]

An enantioselective synthesis of platensimycin, a novel antibiotic natural product that inhibits bacterial β-ketoacyl-(acyl-carrier-protein) synthase (FabF), is described. Our synthetic strategy for the construction of the oxatetracyclic core involved an intramolecular Diels-Alder reaction. Our preliminary studies provided a complex tetracyclic product by first undergoing an interesting 1,5-hydride shift followed by a Diels-Alder reaction. Further optimization of the diene's electronic properties, by incorporation of a methoxy group, led to the oxatetracyclic core of platensimycin. The three required chiral centers, including two all-carbon quaternary chiral centers, were built in the intramolecular Diels-Alder step. The synthesis utilized natural (+)-carvone as the key chiral starting material, which determined the stereochemistry of the final product. The synthesis also featured an efficient Petasis olefination, a hydroboration sequence, a Gais's asymmetric Horner-Wadsworth-Emmons reaction, and a mercury salt catalyzed enol ether isomerization. [ABSTRACT FROM AUTHOR]

Abstract: Treatment of unsaturated [Os3(CO)8{μ3-Ph2PCH2P(Ph)C6H4}(μ-H)] (2) with t BuNC at room temperature gives [Os3(CO)8(CNBu t )){μ3-Ph2PCH2P(Ph)C6H4}(μ-H)] (3) which on thermolysis in refluxing toluene furnishes [Os3(CO)7(CNBu t ){μ3-Ph2PCHP(Ph)C6H4}(μ-H)2] (4). Reaction of the labile complex [Os3(CO)9(μ-dppm)(NCMe)] (5) with t BuNC at room temperature affords the substitution product [Os3(CO)9(μ-dppm)(CNBu t )] (6). Thermolysis of 6 in refluxing toluene gives 4. On the other hand, the reaction of unsaturated [Os3(CO)9{μ3-η2-C7H3(2-Me)NS}(μ-H)] (7) with t BuNC yields the addition product [Os3(CO)9(CNBu t ){μ-η2-C7H3(2-Me)NS}(μ-H)] (8) which on decarbonylation in refluxing toluene gives unsaturated [Os3(CO)8(CNBu t ){μ3-η2-C7H3(2-Me)NS}(μ-H)] (9). Compound 9 reacts with PPh3 at room temperature to give the adduct [Os3(CO)8(PPh3)(CNBu t ){μ-η2-C7H3(2-Me)NS(μ-H)] (10). Compound 8 exists as two isomers in solution whereas 10 occurs in four isomeric forms. The molecular structures of 3, 6, 8, and 10 have been determined by X-ray diffraction studies. [Copyright &y& Elsevier]

The effect of nanoclay on the interlaminar fracture toughness of glass fiber composites was studied. Mode I and mode II tests were conducted to measure the interlaminar fracture toughness of nanoclay reinforced composites. A reduction in interlaminar fracture toughness (both mode I and mode II) was observed in the nanoclay reinforced fiber composites. Alignment of nanoclay along the fiber axis was found to be a possible reason for this reduction. [ABSTRACT FROM AUTHOR]

An enantioselective total synthesis of ()-peloruside A (1) is described. Peloruside A (1) is a potent microtubule stabilizer with significant clinical potential. The synthesis is convergent and involves the assembly of C1−C10 segment 2 and C11−C24 segment 3 by a novel aldol protocol followed by Yamaguchi macrolactonization of the resulting seco-acid, selective methylation of hemi-ketal and removal of the protecting groups to peloruside A. [ABSTRACT FROM AUTHOR]

An enantioselective route to the oxatetracyclic core of (−)-platensimycin (1) has been investigated by using an intramolecular Diels−Alder reaction as the key step. The thermal reaction of E/Zmixture (1:1) provided oxatetracyclic core 2from the E-diene and the Z-diene was recovered unchanged. The Diels−Alder substrate was conveniently assembled in optically active form with use of (S)-carvone as the starting material. [ABSTRACT FROM AUTHOR]

An enantioselective first total synthesis and structural revision of the cytotoxic natural product amphidinolide W is described. We initially investigated a ring-closing metathesis based synthetic strategy to form the 12-membered macrocycle. This strategy was unsuccessful as it led to formation of a 17-membered macrocycle. Subsequently, we explored an alternative strategy that involved cross-metathesis followed by a Yamaguchi macrolactonization reaction sequence utilizing the same key intermediates. This strategy led to the synthesis of amphidinolide W. The synthesis was carried out in a convergent manner, and four of the five stereogenic centers in amphidinolide W were set by asymmetric synthesis. The synthesis features Sharpless asymmetric dihydroxylation, diastereoselective alkylation, efficient cross-metathesis of functionalized substrates, and novel functional group transformations using selective lipase-catalyzed hydrolysis of the primary acetate group. Of particular note, the C6 absolute stereochemistry of amphidinolide W has now been revised through our synthesis. [ABSTRACT FROM AUTHOR]

Dibenzo[def,p]chrysene (DBC) (1), is by far the most mutagenic and toxic polycyclic aromatic hydrocarbon identified. Its metabolic activation leads to trans-11,12dihydroxy-11,12-dihydro-DBC (2), which is further metabolized to the ultimate metabolite, anti-trans-11,12-dihydroxy13,14-epoxy-11,12,13,14-tetrahydro-DBC (3), that binds to DNA causing mutations and ultimately tumor induction. We report a facile route for the syntheses of DBC (1) and its 12-methoxy derivative (12-methoxy-DBC) (13), a key intermediate for the synthesis of 2 and 3, using a Suzuki crosscoupling approach. [ABSTRACT FROM AUTHOR]

Efficient syntheses of important metabolites of 7,12-dimethylbenz[ a ]anthracene (DMBA) and benzo[ c ]chrysene (B[ c ]C), via Suzuki coupling reaction are described. This approach provides an excellent method for the preparation of 3-methoxy-DMBA 5 , 10-methoxy-B[ c ]C 14 and 2-methoxy B[ c ]C 20 , and hence for the corresponding dihydrodiols 6 , 15 , and 21 . Following a similar Suzuki reaction, DMBA-6(5 H )-one 8 was also synthesized in high yield. [ABSTRACT FROM AUTHOR]

Baylis–Hillman reactions on α,β-unsaturated sugar aldehydes with methyl vinyl ketone in the presence of Me2S–TiCl4 have been carried out to provide a convenient strategy for extending the sugar chain in its open form. The resulting Baylis–Hillman adducts have been further used as synthons for synthesising chain extended amino polyols. [Copyright &y& Elsevier]

Abstract: Two new routes were established for the synthesis of biologically active natural product annomontine utilizing Pictet–Spengler and aza-Diels–Alder reactions as key steps. [Copyright &y& Elsevier]

Replacement of the TiO2 layer in a traditional dye sensitized solar cell (DSC) by poly[3-(2-hydroxyethyl)-2,5-thienylene] grafted reduced graphene oxide (PHET-g-rGO) yields an overall power conversion efficiency of 3.06% with the N-719 dye, where the rGO part increases the charge mobility by reducing the backward recombination reaction in the DSC. [ABSTRACT FROM AUTHOR]

Abstract: Oxidative activation of benzyl or cinnamyl ether bearing allylsilane derivatives using a catalytic amount of DDQ and 2equiv of CAN in the presence of PPTS provided functionalized 4-methylenetetrahydropyrans in good yields and excellent diastereoselectivity. The reaction could be applied to the synthesis of a variety of substituted tetrahydropyran derivatives. [Copyright &y& Elsevier]

Abstract: The organotin complex [Ph3SnS(CH2)3SSnPh3] (1) was synthesized by PdCl2 catalyzed reaction between Ph3SnCl and disodium-1,3-propanedithiolate which in turn was prepared from 1,2-propanedithiol and sodium in refluxing THF. Reaction of 1 with Ru3(CO)12 in refluxing THF affords the mononuclear complex trans-[Ru(CO)4(SnPh3)2] (2) and the dinuclear complex [Ru2(CO)6(μ-κ2-SCH2CH2CH2S)] (3) in 20 and 11% yields, respectively, formed by cleavage of Sn–S bond of the ligand and Ru–Ru bonds of the cluster. Treatment of pymSSnPPh3 (pymS=pyrimidine-2-thiolate) with Ru3(CO)12 at 55–60°C also gives 2 in 38% yield. Both 1 and 2 have been characterized by a combination of spectroscopic data and single crystal X-ray diffraction analysis. [Copyright &y& Elsevier]

Alterations of cell surface properties accompanying the complex life cycle of Termitomyces clypeatushave been monitored using atomic force microscopy (AFM). A new hyphae/mycelium is developed on cell division, and the cell wall of the mycelium undergoes a process of internal reorganization (or maturation) followed by morphological and chemical alterations. The changes of the surface ultrastructures during the growth process are correlated to the corresponding changes in relative viscoelasticity and rigidity of the cell wall by employing force spectroscopy. The cell wall rigidity and elasticity are found to be 0.34 ± 0.02 N/m and 27.5 ± 2.1 MPa, respectively, at the early logarithmic phase, on maturation increase to reach 0.81 ± 0.08 N/m and 92.5 ± 12 MPa, respectively, at the stationary phase, and thereafter decrease to 0.62 ± 0.06 N/m and 61.6 ± 6.6 MPa at the death phase. The alterations of the ultrastructural and nanomechanical properties of the cell surface as functions of growth phases affect the interaction involving chromium and T. clypeatus. [ABSTRACT FROM AUTHOR]

Abstract: An efficient method to obtain novel tetrasubstituted tetrahydrofurans with C2 and C5 substitution in trans- and cis-relative configurations has been reported. [Copyright &y& Elsevier]

Abstract: Solid-supported nano and microparticles of Pd(0) (SS-Pd) were prepared and used as heterogeneous catalysts for Suzuki–Miyaura cross coupling reactions of aryl halides (chloro, bromo and iodo) and phenyl boronic acid under mild and ligand-free conditions. Scanning electron microscope (SEM) and UV–vis based studies were performed to observe the distribution of nano and microparticles of palladium over solid surface and their oxidation states. In addition, the catalyst could be reused up to seven runs without significant loss of activity and stable enough under moist conditions. [Copyright &y& Elsevier]

Bovine serum albumin (BSA) has been explored for aerobic oxidative coupling of thiols (aromatic, heterocyclic as well as aliphatic) “on water” towards formation of disulphides (S S) without using any metal/non-metal complexes, bases and additives, which renders the process environmentally benign and economically attractive with good recyclability (up to four cycles). The developed green protocol was further extended for synthesis of diallyldisulphide (DADS), an important constituent of natural occurring allicin. Among various synthesized disulphides, bis(2-aminophenyl)disulphide, obtained by oxidative coupling of 2-aminothiophenol in BSA, was further utilized for condensation with benzaldehyde in the same pot thus enabling easy access to bioactive dithiobis(phenylene)bis(benzyldeneimine). This is the first example of BSA catalysed sequential (oxidation/condensation) reaction where one S S and two C N bonds are formed solely “on water.” [ABSTRACT FROM AUTHOR]

Abstract: In continuation of our efforts to find new biologically active agents, regioselective synthesis of a series of 2-(3,5-dimethyl-1H-pyrazol-1-yl)-1-arylethanones 4a–k has been achieved under facile, extremely mild and greener reaction conditions with excellent yields. Moreover, one pot multicomponent reaction has also been reinvestigated under previously reported solvent conditions to prepare 4a–b and found that the reaction generates significant amount of side products. The chemical structures of 4a–k were established on the basis of a combined use of IR, NMR (1H, 13C) spectroscopy, mass spectrometry and elemental analysis. All the compounds were evaluated for their antibacterial, DNA photocleavage and anticancer activities. Among all, 2-(3,5-dimethyl-1H-pyrazol-1-yl)-1-(naphth-2-yl)ethanone 4j displayed good inhibitory profile against Escherichia coli and Staphylococcus aureus which was about 50% and 25% of the Ampicillin (standard drug), respectively. The compounds, 4a and 4f showed relatively moderate inhibition against Psuedomonas aeruginosa and E. coli. In DNA photocleavage study, compounds 4c and 4d were found to be highly active and completely degraded both forms of DNA (SC and OC), even at a very low concentration of 1 μg (4c) under irradiation of UV light. However, 4h and 4f resulted in complete DNA degradation at 30 μg concentration. Moreover, 4h showed fluorescence at 15 μg concentration and increased the intensity of both bands of DNA (SC and OC) as compared to control. On the other hand, to valorize the biological potential, the compounds were screened for their cytotoxic activity on colon (HCT116 and HT29), prostate (DU145), ovarian (SKOV3) and lung (A549) cancer cell lines. The compound 4j was found to be cytotoxic to all the cancer cell lines, except SKOV3, with more selectivity towards the colon cancer cell lines (HCT116, HT29) and A549 lung cancer cell line. On A549 lung cancer cell line, 4j and 4k exhibited similar potency as carboplatin in inhibiting cell viability. [Copyright &y& Elsevier]

Reactions of acyclic and cyclic organotellurium (IV) compounds [R2TeI2 {R2 = (C2H5)2, (n-C3H7)2, C5H10}] with the silver salt of carboxylic acids and sodium diethyldithiocarbamate form the organotellurium (IV) complexes (C2H5)2Te(4-NO2C6H4OCO)2 (1), (C2H5)2Te(C6H5CHᆖCHOCO)2 (2), (n-C3H7)2Te(C6H5OCO)2 (3), (n-C3H7)2Te(4-NO2C6H4OCO)2 (4), (n-C3H7)2Te(3,5-NO2C6H3OCO)2 (5), (n-C3H7)2Te(4-OCH3C6H4OCO)2 (6), (n-C3H7)2Te(C6H5CHᆖCHOCO)2 (7), C5H10Te(C6H5CHᆖCHOCO)2 (8) and C5H10TeCl[SᆖCSN-(C2H5)2] (9). The X-ray structures of some of these organotellurium (IV) derivatives indicate that they possess ψTBP geometry and dimeric and tetrameric supramolecular associations are achieved through cooperative participation of inter- and/or intramolecular Te···O secondary bonds and/or C–H···O hydrogen bonds. The intramolecular Te···O secondary bond lengths seem to be dependent on the cis- and trans-position placements of free oxygens of the carboxylate groups. It is found that the third-order non-linear optical susceptibilities (χ(3)) of these complexes are in the range 7.21–8.20 × 10−14 esu and the second order hyperpolarizabilities (γ) are in the range 4.89–5.56 × 10−32 esu. The presence of the telluracyclopentane (C5H10Te) cyclic organic group and cinnamate (C6H5CHᆖCHOCO)/diethyldithiocarbamate (SᆖCSN(C2H5)2) ligands having conjugation in the organotellurium (IV) derivatives (8 and 9), appears to be responsible for the higher χ(3) and γ values. [Copyright &y& Elsevier]

The development of an innovative method to access enantiopure 2,4-disubstituted 6-hydroxy-1,6-dihydro-2H-pyridin-3-ones starting from D-glucal via the aza-Achmatowicz transformation has been described. These highly functionalized pyridin-3-ones have been utilized for the synthesis of contiguously substituted pyridines through a rapid and efficient Et3N/Ac2O promoted cycloelimination, aromatization cascade, allowing the facile assembly of important pyridine-based building blocks like 2-substituted 3-acetoxy-4-iodopyridines and enantiopure 2-substituted 3-acetoxy-4-pyridinemethanols possessing benzylic stereogenic centers, whose synthesis otherwise would be tedious. The utilization of commercially available sugars as starting materials, mild reaction conditions, catalytic transfer hydrogen (CTH) of α-furfuryl azide derivatives, transfer of chiral aryl/alkyl methanols from enulosides to pyridin-3-ones and pyridines, high yields, and short reaction times are key features of this method- The utility of the method has been further exemplified by demonstrating the usage of the 2-substituted 3-acetoxy-4-iodopyridine for the construction of biologically significant molecules like 2,7-disubstituted furo[2,3-c]pyridines and 7,7'-disubstituted 2,2'-bifuro[2,3-c]pyridines. [ABSTRACT FROM AUTHOR]

Abstract: (+)-4-epi-Gabosine A 1 and (−)-gabosine A 2 have been synthesized starting from methyl α,d-glucopyranoside and methyl α,d-mannopyranoside, respectively, by utilizing Pd(0) catalyzed Stille coupling as the key step. On the other hand, syntheses of (+)-4-epi-gabosine E 3 and (−)-gabosine E 4 have been accomplished from methyl α,d-glucopyranoside and from methyl α,d-mannopyranoside, respectively, by utilizing DMAP catalyzed Morita–Baylis–Hillman reaction as the key step. Presence of acetyl group at C-6 position of sugar derived cyclic enone prevented the aromatization of MBH adduct. A plausible mechanism is also described. [Copyright &y& Elsevier]

Abstract: Three pairs of enantiomeric 2′-deoxynucleoside analogues 4a, 4b, 4c, 4e and 4d, 4f, respectively, have been synthesized from enantiomerically pure highly functionalized furanoid glycals 2a–d by involving a similar synthetic strategy. These analogues have various well defined stereogenic centres and are useful building blocks for deoxynucleoside chemistry. [Copyright &y& Elsevier]

Abstract: Mucor rouxii biomass (MRB) was found to be most potent sorbent for the removal of copper from its aqueous solution. Maximum adsorption was noted within pH range 5.0–6.0, and the process follows Langmuir adsorption isotherm (r 2 =0.998). Adsorption process is very fast initially and reaches equilibrium very quickly following pseudo second order rate kinetics. Amino, carboxyl and phosphate groups present on the cell surface of the biomass are involved in chemical interaction with copper ion as revealed from FTIR and SEM-EDX study and also by blocking experiments. Both SEM and AFM micrographs revealed the formation of metal nanostructure on the biomass surface due to copper adsorption. Biomass surface modification indicates the major involvement of amino functional group for the binding probably through the chelation. Copper ion can be eluted from the adsorbed biomass with 0.1M hydrochloric acid. [Copyright &y& Elsevier]

Abstract: A highly efficient, consecutive approach for the construction of synthetically valued, enantiomerically pure, trisubstituted THF domains 3–10 in a stereoselective manner starting from glycal derived allylic alcohols 1a–1d under Sharpless asymmetric epoxidation (SAE) conditions is reported. The reaction involves the intramolecular asymmetric ring opening (ARO) of in situ formed enantiopure 2,3-epoxy alcohols followed by protection of the diol. [Copyright &y& Elsevier]

Abstract: Background: Pressure stimulates colon cancer adhesion via focal adhesion kinase (FAK). Extracellular pressures reaching 29 mm Hg have been reported in rapidly growing breast cancers, and tumors experience pressure during surgical manipulation. We hypothesized that pressure stimulates breast cancer adhesion and that CARP-1, which influences cancer biology, inhibits FAK, and modulates pressure effects. Methods: We compared MDA-MB-468 breast cancer cells under ambient or 15-mm Hg increased pressure. We studied FAK-397 autophosphorylation, which parallels activation, after CARP-1 overexpression, and investigated whether CARP-1 stable overexpression or reduction alters pressure-stimulated adhesion. Results: Pressure increased MDA-MB-468 adhesion 25% (n = 30, P < .05). CARP-1 overexpression inhibited FAK-397 phosphorylation. However, pressure stimulated adhesion equivalently in CARP-1–overexpressing and CARP-1–reduced lines (n = 6, P < .05). Conclusions: Pressure within proliferative tumors or during manipulation may activate breast cancer cells. Thus, inhibiting pressure signaling in rapidly growing breast tumors may be beneficial. CARP-1 does regulate FAK, but CARP-1 modulation does not alter pressure-stimulated adhesion. Targeting CARP-1 is unlikely to manipulate this pathway. [Copyright &y& Elsevier]

The Morita–Baylis–Hillman (MBH) reaction of p-nitrobenzaldehyde with C (6) acyl protected enuloside 1 in the presence of TiCl4/TBAI yielded highly diastereoenriched C-3-branched deoxysugar derivative or MBH adduct 1′a in high yield, while reactions of unprotected enuloside 2a and C (6) alkyl protected enulosides 2d–e with p-nitrobenzaldehyde under the same conditions afforded the adducts 2′a and 2′d–e, respectively, in low yield with moderate selectivity. Several representative aromatic and aliphatic aldehydes were selected to undergo MBH reaction with 1 to give their respective adducts in very good yield with a very high diastereoselectivity. A plausible mechanism based on the assumption of a Zimmerman–Traxler-type transition state was proposed to explain the excellent selectivity observed with adducts derived from 1. The synthetic application of these adducts were shown by their stereoselective reduction to corresponding threo isomers in very good yield. [Copyright &y& Elsevier]