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The volumetric properties and taste behaviour of sucrose in aqueous solutions of a protic ionic liquid (3-hydroxypropylammonium acetate) have been studied at temperatures, T = (293.15-318.15) K and at atmospheric pressure. Apparent molar volumes, V2,?, apparent specific volumes, ASV, apparent molar isentropic compressibilities, Ks,2,?, and apparent specific isentropic compressibilities, ASIC, were calculated from measured density, ? and speed of sound, u data. Partial molar volumes, V 2 �, and partial molar isentropic compressibilities, Ks,2 � at infinite dilution, transfer parameters (?tV2 � and ?tK s,2 �), expansion coefficients, [(?V 2 �/?T)P and (?2V 2 �/?T2)P], interaction coefficients, (YAB and YABB) and hydration numbers, N w, were also evaluated and discussed in terms of solute-cosolute interactions. Further, the effect of protic ionic liquid on the taste behaviour of sucrose has been discussed from ASV and ASIC parameters, as these parameters, which are sensitive to solvation behaviour of solute, are divided into four basic taste qualities occupying certain ranges. � 2014 Elsevier Ltd. All rights reserved.

A library of ring-A-monosubstituted chalcone derivatives (4a-4i, 5a and 5b) was designed and synthesised. The structures as well as the identities of these compounds were established on the basis of spectral (1H NMR, 13C NMR, FT-IR and Mass) and elemental (C, H, N) analyses. All the derivatives were evaluated for their antiinflammatory and antioxidant activities in vitro using the inhibition of protein denaturation and 2,2-diphenyl-1-picrylhydrazyl radical scavenging assays, respectively. The results indicated a promising anti-inflammatory activity for most of the synthesised compounds with many derivatives showing activities similar to or greater than that of the standard. The sulphonamide-substituted chalcones 4h, 4i, 5a and 5b were found to be the most active derivatives across the concentration range tested. However, all the derivatives exhibited rather mild antioxidant activity compared to the ascorbic acid standard. Interestingly, it was observed that the unsubstituted parent chalcone was one of the optimal compounds with only the trifluoromethyl analogue 4a showing better activity as an antioxidant. The two regioisomeric aminochalcones and 4?cyanochalcone 4b also seemed to possess decent antioxidant potential. � Springer Science+Business Media New York 2014.

A complete library of new alkoxides containing group 4 metals and the imino phenol ligand were synthesized in high yields and purity. These compounds showed catalytic activity towards the polymerization of l-lactide (l-LA), rac-lactide (rac-LA), ?-caprolactone (CL), ?-valerolactone (VL), rac-?-butyrolactone (rac-BL), ethylene and propylene. The zirconium catalysts were found to yield better polymerization results in comparison to the titanium and hafnium analogues. The number average molecular weight (M n) values of the polymers are very high for LA and CL with controlled molecular weight distributions (MWDs). Analyses of MALDI-TOF and 1H NMR spectra of low Mn oligomers reveal that the ligand initiates the ring-opening polymerization (ROP). For ethylene and propylene polymerization, we have achieved moderate to good activity using MAO as a co-catalyst. � 2013 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

D-gluco-Configured building block derived from d-(+)-gluconolactone has served as a common chiral template for the synthesis of enantiopure d- and l-xylo-configured 1,2,3,4-alkane tetrols. This has enabled synthesis of medicinally important guggultetrols and their enantiomers from a common starting point. Wittig and Grignard reactions are the key steps used for the incorporation of lipophilic chain. � 2012 Elsevier Ltd. All rights reserved.

We report the first high temperature solution state synthesis of glutathione (-SG) protected atomically precise silver clusters. Noble metal cluster synthesis from metal ions generally requires ice cold temperatures as they are extremely sensitive and high temperature routes are used only for core reduction methods, starting from nanoparticles. The clusters formed by the new route have distinct features in their absorption profile and they exhibit red luminescence. They are characterised by other spectroscopic and microscopic techniques and a tentative formula of Ag 75(SG) 40 has been assigned. � The Royal Society of Chemistry 2012.

Some novel techniques for volume localized, chemical shift selective 13C spectroscopy are described in this work. These techniques are based on rotating frame J cross polarization and are reported for both direct and indirect modes of 13C detection. The performance of two selective mixing sequences, viz., pulsed rotating frame transfer sequences with windows (PRAWN) and PRAWN-? has been studied systematically with different liquid and gel phantoms. Two different front-end modules are used for volume localization, viz., point resolved spectroscopy (PRESS) and localized distortionless enhancement by polarization transfer (LODEPT). It is shown experimentally that both the selective J cross polarization sequences can operate efficiently with very low radiofrequency duty cycle; further, they have considerable tolerance to Hartmann-Hahn mismatch. A simple theoretical analysis is also presented to understand J cross-polarization dynamics at low RF field amplitudes. Finally, the performance of LODEPT-PRAWN-? is demonstrated for the selective detection of saturated fat in pigeon egg in indirect detection mode. Copyright � 2011 Wiley Periodicals, Inc.

A new procedure for the selective and direct oxidation of aliphatic primary alcohols having substitution at - and -positions to corresponding carboxylic acids was developed using a catalytic amount of ligand and additive-free CuCl with anhydrous tBuOOH in acetonitrile solvent under very mild reaction conditions. This procedure is very simple and mild and works efficiently without any additives at room temperature. � 2010 Taylor & Francis Group, LLC.

Novel sixteen chalcones and thirteen 1,3,5-triphenyl-2-pyrazolines were synthesized and characterized using FT-IR, HR-Mass, NMR (1H-NMR, 13C-NMR, 135 DEPT, 1H-1H CoSY and 1H and 13C CoSY) and XRD. These compounds were evaluated for their antibacterial activity against six micro-organisms, namely Bacillus subtilis NCIM 2718, Staphylococcus aureus NCIM 5021, Salmonella typhi NCIM 2501, Enterobacter aerogenes NCIM 5139, Pseudomonas aeruginosa NCIM 5029, and Proteus vulgaris NCIM 2813 by twofold dilution method using resazurin as the indicator dye. In the case of chalcones, compounds with hydroxyl and bromo substitutions in the B-ring favor activity and benzyloxy substitution irrespective of its position in the A-ring. In the case of 1,3,5-triphenyl-2-pyrazolines, chloro substitution in the A-ring favors activity. Hydrophilic/lipophilic balance of the compounds plays a major role in their antibacterial activity. � 2010 John Wiley & Sons A/S.

Racemic alkyl-2-hydroxy-4-arylbut-3-ynoates were deracemized to the (S)-alkyl-2-hydroxy-4-arylbut-3-ynoates in excellent enantiomeric excesses (up to >99%) and good isolated yields (up to 81%) with the biocatalyst Candida parapsilosis ATCC 7330. The absolute configuration of the resulting enantiomer was assigned by 1H NMR using Mosher's method. � 2010 Elsevier Ltd. All rights reserved.

There has been much recent progress in using NMR chemical shift anisotropy (CSA) parameters to gain information about secondary structure content in proteins. This paper focuses on the comparison of CSA tensors of different backbone nuclei (namely 13Ca, 13C?, 15N, 1Ha, 1HN) of all twenty amino acids appearing in well-defined secondary structures such as helices and sheets. Dihedral angle information of these backbone nuclei in different secondary structure elements has been extracted from experimentally determined structures of proteins deposited in the protein databank. The CSA tensors of these backbone nuclei have been computed for the corresponding dihedral angles using ab initio quantum chemical methods. It is shown that 2D correlated plots of a novel set of CSA parameters (?,?), that define the magnitude and shape of the anisotropy, are extremely useful in identifying secondary structure content. Further, multinuclear correlations between these CSA parameters can clearly distinguish between various secondary structure elements such as helices and sheets. �Adenine Press (2010).

Reduction of the ?-cell mass is critical in the pathogenesis of diabetes mellitus. The discovery of agents which induce regeneration of pancreatic ?-cells would be useful to develop new therapeutic approaches to treat diabetes. The present study was aimed at identifying a new agent for the control of diabetes through regeneration of pancreatic ? cells and insulin secretory potential. Nymphaea stellata flower chloroform extract (NSFCExt) showed significant plasma glucose lowering effect. Further NSFCExt was utilized to isolate and identify the lead compound based on bioassay guided fractionation; we found Nymphayol (25,26-dinorcholest-5-en-3?-ol) a new crystal [space group P21 (No. 4), a = 9.618(5), b = 7.518(5), c = 37.491(5)]. It was purified by repeat column. The structure was determined on the basis of X-ray crystallography and spectral data. Oral administration of Nymphayol for 45 days significantly (p < 0.05) lowered the blood glucose level and more importantly it effectively increased the insulin content in diabetic rats. In addition, Nymphayol increased the number of ? cell mass enormously. Islet-like cell clusters in the islets of Langerhans were clearly observed based on histochemical and immunohistochemical study. � 2009 Elsevier Ltd. All rights reserved.

H-Beta zeolite, a microporous solid acid, is demonstrated to be an efficient catalyst for the selective deprotection of cyclic as well as acyclic O-isopropylidene sugar acetals derived from d-glucose, d-xylose, d-mannose, and d-mannitol in aqueous MeOH at room temperature. A notable observation is the conversion of d-mannitol triacetonide into 1,2:3,4-di-O-isopropylidene-d-mannitol (48%) and 3,4-O-isopropylidene-d-mannitol (36%) brought about in 6 h by H-beta zeolite and the non-occurrence of any hydrolysis in the case of H-ZSM-5 catalyzed reaction in 24 h under the same conditions. � 2008 Elsevier Ltd. All rights reserved.

The anisotropic effect of the planar nitrate anion NO3 - has been ab initio calculated employing the Nucleus-Independent Chemical Shift (NICS) concept of von Ragu� Schleyer and visualized as Iso-Chemical-Shielding Surfaces (ICSSs) of various (de)shieldings. Complexation-induced shifts in the 1H NMR spectra of�nitrate/metal complexes or nitrate/receptor supramolecules can be separated now into anisotropic influences of the suitably coordinated nitrate anions and effects originating from differential sources. � 2008 Elsevier Ltd. All rights reserved.

Deracemisation of racemic (3E)-alkyl-4-(hetero-2-yl)-2-hydroxybut-3-enoates using Candida parapsilosis ATCC 7330 resulted in the formation of one enantiomer in high enantiomeric excess [up to >99% ee] and isolated yields [up to 79%]. The absolute configuration of the enantiomerically pure (3E)-ethyl-4-(thiophene-2-yl)-2-hydroxybut-3-enoate as determined by 1H NMR of the Mosher esters was found to be (S). � 2007 Elsevier Ltd. All rights reserved.

An efficient (in terms of experiment and time) synthetic procedure for chloromethyl methyl ether (MOM-Cl) is described using heteropolyacids as catalysts.

The acetylation of several alcohols, phenols, thiols and amines was effected at room temperature in excellent yields using H-beta zeolite as catalyst and acetic anhydride as acetylating agent under mostly solvent-free conditions.

Isoniazid, an anti-tuberculosis (TB) drug has been coordinated with chromium, molybdenum, and tungsten metal carbonyls and three new zero-valent complexes fac-[M(CO)3(isoniazid)3] (M = Cr, Mo, and W; 4, 5, and 6) (isoniazid = 4-H2NHNOCC5H4N) have been synthesized. Reaction of the complex precursors fac-[M(CO) 3(CH3CN)3] (M = Cr, Mo, and W; 1, 2, and 3) prepared 'in situ' with three equivalents of isoniazid in methanol at room temperature afforded high yields of isoniazid substituted metal carbonyl complexes 4, 5, and 6. The complexes have been characterized by elemental analyses, mass analysis, thermal analysis (TGA, EGA), FT-IR, UV/visible and 1H NMR spectroscopic techniques and powder X-ray diffraction (XRD). The FT-IR (KBr and methanol solution) spectra of the complexes 4, 5, and 6 exhibit two bands corresponding to v(C�O) of metal carbonyl groups and v(C=O) of coordinated isoniazid molecules. The bulky -CONHNH2 group of isoniazid molecules made more impact on the M-C bond strength of metal carbonyls and affects their fundamental modes of vibrations leading to the appearance of more number of v(C�O) bands. These steric effects are also reflected in the 1H NMR spectral features of the complexes when considering the complexes as a whole, wherein the four protons on the pyridine ring of the coordinated isoniazid molecules resonate at different chemical shifts. All the three complexes exhibit similar XRD pattern suggesting similar geometry.

The reaction of py2Te2 or (3-MeC5H3N)2Te2 with Na2PdCl4 in methanol yields an insoluble brown complex, [PdCI(TeNC5H3R)]n (R=H or Me). Several reactions of pyTe-, (3-MeC5H3N)Te-, or (6-MeC5H3N)Te- with various palladium(II) and platinum(II) complexes have been carried out. Complexes of the types [MCl(Te-N)(PR3)], [Pt(Te-N)2(dppe)], [Pt(Te-N)2(PPh3)2], and [Pt2(?-Te-N)2(dppe)2] [BPh4]2 [M=Pd or Pt; Te-N = pyTe, (3- or 6-MeC5H3N)Te] have been prepared and characterized by elemental analyses, UV/Vis, IR, and NMR (1H, 31p, 195Pt) spectroscopy. The complexes [MCl(Te-N)(PR3)] show irreversible oxidation and reduction by CV in DMF. The molecular structure of [PdCl{Te(3MeC5H3N)}(PPh3)] (2c) has been established by single-crystal X-ray diffraction analysis. The palladium atom is bound to the chelating 3-methylpyridinetellurolate ligand, a chlorine atom and a PPh3 ligand. The pyrolysis of [PdClTe(3MeC5H3N)}(PR3)] (PR3=PEt3 or PPh3) at 340 �C yields PdTe. ? Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.

The interaction of H2S gas with aqueous ammonium heptamolybdate solution in the presence of diethylenetriamine (dien) led to the formation of diethylenetriammonium tetrathiomolybdate crystals. The elemental analyses, UV-Visible, IR, and 1H NMR spectra suggested the presence of organic cation and (MoS4)2- moiety. The 1H NMR revealed the presence of two sets of symmetrical A2X2 multiple patterns. The compound crystallizes in the monoclinic system with space group Pn, a = 7.196(6), b = 7.532(3), c = 11.525(10) �, � = 90�, ? = 90.17(3)�, ? = 90�, V = 624.78(8) �3, and Z = 2, wR1 = 0.0261 and wR2 = 0.0698. The structure consists of tetrahedral tetrathiomolybdate anions, which form an extended three-dimensional network in the solid state with Mo-S?H-N hydrogen bonding with the organic cation.

The present work reports the synthesis of an octaester porphyrin and its Zn(II) complex which shows an unusual two-dimensional supramolecular coordination network structure. ? 2002 Elsevier Science Ltd. All rights reserved.

Three new nicotinamide coordinated group VI B metal carbonyl complexes fac-[M(CO)3(nicotinamide)3] (M = Cr, Mo, and W; 4, 5, and 6) (nicotinamide = 3-H2NOCC5H4N) have been synthesized. Reaction of the 'in situ' generated complex precursors fac-[M(CO)3(CH3CN)3] (M = Cr, Mo, and W: 1, 2, and 3) with three equivalents of nicotinamide in methanol at room temperature give nicotinamide coordinated metal carbonyl complexes 4, 5, and 6 in good yields. The complexes exhibit two bands corresponding to v(C�O) of metal carbonyl groups and v(C=O) of nicotinamide ligands. All the complexes exhibit a very strong stretching band corresponding to v(C=O) of coordinated nicotinamide ligands at 1684 (Cr, 4); 1669 (Mo, 5); and 1683 cm.1 (W, 6). The occurrence of single v(C=O) band suggests the coordination of three nicotinamide molecules that are arranged cis to each other and representing a C3v configuration of ligands around the metal atom in the facial geometry of the complexes. The 1H NMR spectra of the complexes shows signals at four different chemical shift regions, corresponding to the four protons on the pyridine ring of the nicotinamide ligand. The calculated integral value of each signal is present in the ratio 1:1:2:2. The powder X-ray diffractogram of the complexes exhibit similar pattern suggesting the similar arrangements of atoms in the crystal lattice and geometry.

Two novel chiral rhodium complexes were successfully synthesized from the reaction of chiral bidentate nitrogen ligands with RhCl3-3H2O in ethanol under reflux. Their unusual crystal structures were unambiguously obtained by X-ray analysis. Copyright ? 2001 John Wiley & Sons, Ltd.

The design, synthesis, and characterization of binuclear copper(I) complexes and investigations of their dioxygen reactivities are of interest in understanding fundamental aspects of copper/O2 reactivity and in modeling copper enzyme active-site chemistry. In the latter regard, unsymmetrical binuclear systems are of interest. Here, we describe the chemistry of new unsymmetrical binuclear copper complexes, starting with the binucleating ligand UN2-H, possessing a m-xylyl moiety linking a bis[2-(2-pyridyl)ethyl]amine (PY2) tridentate chelator and a 2-[2-(methylamino)ethyl]pyridine bidentate group. Dicopper(I) complexes of UN2-H, [Cu2(UN2-H)]2+ (1), as PF6- and ClO4- salts, are synthesized. These react with O2 (Cu:O2 = 2:1, manometry) resulting in the hydroxylation of the xylyl moiety, producing the phenoxohydroxodicopper(II) complex [Cu2(UN2-O-)(OH-)(CH3CN)]2+ (2). Compound 2(PF6)2 is characterized by X-ray crystallography, which reveals features similar to those of a structure described previously (Karlin, K. D.; et al. J. Am. Chem. Soc. 1984, 106, 2121-2128) for a symmetrical binucleating analogue having two tridentate PY2 moieties; here a CH3CN ligand replaces one pyridylethyl arm. Isotope labeling from a reaction of 1 using 18O2 shows that the ligand UN2-OH, extracted from 2, possesses an 18O-labeled phenol oxygen atom. Thus, the transformation 1 + O2--2 represents a monooxygenase model system. [CuI2(UN2-OH)(CH3CN)]2+ (3), a new binuclear dicopper(I) complex with an unsymmetrical coordination environment is generated either by reduction of 2 with diphenylhydrazine or in reactions of cuprous salts with UN2-OH. Complex 3 reacts with O2 at -80 degrees C, producing the (mu-1,1-hydroperoxo)dicopper(II) complex [CuII2(UN2-O-)(OOH-)]2+ (4) (lambda max 390 nm (epsilon 4200 M-1 cm-1), formulated on the basis of the stoichiometry of O2 uptake by 3 (Cu:O2 = 2:1, manometry), its reaction with PPh3 giving O=PPh3 (85%), and comparison to previously studied close analogues. Discussions include the relevance and comparison to other copper bioinorganic chemistry.

Di-O-isopropylidene sugar derivatives (1a-9a) on treatment with a solution of Zn(NO3)2�6H2O in acetonitrile, undergo regioselective hydrolysis to furnish the corresponding diols (1b-9b) in excellent yields.

A systematic study of alkylation of cyclic-1,3-diones with 2-bromo-6-methoxybenzofuran-3-one was undertaken. Upon condensation in acetic acid with p-substituted aniline the O-alkylated product 3a gave condensed ?-lactam heterocycle 4. In contrast, the condensation of analogous O-alkylated derivatives 3b and 3c with p-substituted anilines furnished the substituted xanthone derivatives 6 and 7a. The probable mechanism of formation of 4, 6 and 7a was discussed. (C) 2000 Elsevier Science Ltd.

Complexes of types [Pd(CH3COO)(na)])xH2O, Hna=adenine (Hade) or guanosine (Hguo), x=2 � or 3; [Pd(CH3COO)2 (0.5 Hado)]2H2O, Hado=adenosine; [Pd(NH3)(na)(aa)3H2O, Hna=Hguo or inosine (Hino), Haa=glycine or alanine and [Pd(NH3)(gly)(0.5 ade)]2NO3H2O have been synthesised and characterized by elemental and thermal analyses, electronic, infrared, 1H NMR spectral and XPS studies. In acetato complexes, adeninate and guanosinate act as bridging ligand through the ring nitrogens N3 or N1 and N9, and N1 and N7 respectively giving polymeric structure while adenosine bridges the Pd(II) centers through N1 and N7. In amino acidato complexes, nucleosides coordinate through N1 to Pd(II) and adeninate bridges the two adjacent Pd(II) through N1 or N3 and N9.

1 H, 13 C and ATR-FTIR spectroscopic studies reveal that the asymmetric cyclization of prochiral triones 1 and 2 in the presence of S -proline is a template reaction.

Treatment of 3,4-dihydro-2H-pyran 1 with various alcohols 2 - 10 furnished the tetrahydropyranyl ethers 11 - 19 in the presence of lithium tetrafluoroborate in acetonitrile (LTAN).

Treatment of 3,4-dihydro-2H-pyran 1 with various alcohols 2 - 10 furnished the tetrahydropyranyl ethers 11 - 19 in the presence of 5M lithium perchlorate in diethyl ether (5M LPDE), which is essentially a neutral medium.