An efficient one-pot synthesis of substituted 2-arylbenzo[b]thiophene derivatives

This communication describes an efficient one-pot procedure for the synthesis of 2-arylbenzo[b]thiophene derivatives via reaction of o-halo or nitro aryl carbonyl compounds with benzyl mercaptans in the presence of an excess of anhydrous K₂CO₃ at elevated temperature.     

Glutaraldehyde activated eggshell membrane for immobilization of tyrosinase from Amorphophallus companulatus: application in construction of electrochemical biosensor for dopamine

Tyrosinase from a plant source Amorphophallus companulatus was immobilized on eggshell membrane using glutaraldehyde. Among the three different approaches used for immobilization, activation of eggshell membrane by glutaraldehyde followed by enzyme adsorption on activated support could stabilize the enzyme tyrosinase and was found to be effective. K_m and V_max values for dopamine hydrochloride calculated from Lineweaver-Burk plot were 0.67 mM and 0.08 mM min⁻¹, respectively. Studies on effect of pH showed retention of more than 90% activity over a pH range 5.0-6.5. Membrane bound enzyme exhibited consistent activity in the temperature range 20-45 °C. Shelf life of immobilized tyrosinase system was found to be more than 6 months when stored in phosphate buffer at 4 °C. An electrochemical biosensor for dopamine was developed by mounting the tyrosinase immobilized eggshell membrane on the surface of glassy carbon electrode. Dopamine concentrations were determined by the direct reduction of biocatalytically liberated quinone species at −0.19 V versus Ag/AgCl (3 M KCl). Linearity was observed within the range of 50-250 μM with a detection limit of 25 μM.     

Manganese(II) complexes of biological relevance: Synthesis and spectroscopic characterization of novel manganese(II) complexes with monobasic bidentate ligands derived from halo-substituted 1H-indole-2,3-diones

Russian Journal of General Chemistry - Novel biologically significant manganese(II) complexes with four monobasic bidentate ligands L1H...     

Group algebras of Lie nilpotency index 12 and 13

Let G be a group and let K be a field of characteristic p>0. Lie nilpotent group algebras of strong Lie nilpotency index up to 11 have already been classified. In this paper, our aim is to classify the group algebras KG which are strongly Lie nilpotent of index 12 or 13.     

Charge transfer interaction and nonlinear optical properties of barium chloride and thiourea complexes: a vibrational spectroscopic study

The nonlinear optical (NLO) semiorganic crystals barium thiourea chloride (BTC), bis(thiourea)barium chloride (BTBC) and barium(tetrakisthiourea) chloride (BTTC) were grown by the slow evaporation technique. FT‐Raman and IR spectra of the crystallized NLO materials were recorded and analyzed. The equilibrium geometry, bonding features and harmonic vibrational wavenumbers were investigated with the help of B3LYP density functional theory (DFT) method. From the optimized geometry, the decrease in C N bond length indicates the charge delocalization over the region of the molecules. Lengthening of CS bond and the deviation of CS···Cl angles clearly show the coplanarity of the amide planes of the complexes. The lowering of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy gap appears to be the cause for its enhanced charge transfer interactions. Copyright © 2011 John Wiley & Sons, Ltd.     

Glycol modified titanosiloxane as molecular precursor for homogenous titania–silica material: synthesis and characterization

Ti(OPrⁱ)₄ reacts with HOSi(O^tBu)₃ in anhydrous benzene in 1:1 and 1:2 molar ratios to afford alkoxy titanosiloxane precursors, [Ti(OPrⁱ)₃{OSi(O^tBu)₃}] (A) and [Ti(OPrⁱ)₂{OSi(O^tBu)₃}₂] (B), respectively. Further reactions of (A) or (B) with glycols in 1:1 molar ratio afforded six complexes of the types [Ti(OPrⁱ)(O–G–O){OSi(O^tBu)₃}] (1A–3A) and [Ti(O–G–O){OSi(O^tBu)₃}₂] (1B–3B), respectively [where G = (CH₂)₂ (1A, 1B); (CH₂)₃ (2A, 2B) and {CH₂CH₂CH(CH₃)} (3A, 3B)]. Both (A) and (B) are liquids while all the other products are viscous liquids which get solidified on ageing. Cryoscopic molecular weight measurements of the fresh products indicate their monomeric nature. FAB mass studies of (A) and (B) also indicate monomeric nature. However, FAB mass spectra of the two representative solids (1A) and (2B) suggest dimeric behavior of the glycolato derivatives. (A) distills at 85 °C/5 mm while other products get decomposed even under reduced pressure. TG analyses of (A), (B), (1A), and (1B) suggest formation of titania–silica materials at 200 °C for (A) and (B) and 350 °C for (1A) and (1B). The products have been characterized by elemental analyses, FTIR and ¹H, ¹³C & ²⁹Si-NMR techniques. All these products are soluble in common organic solvents indicating a homogenous distribution of the components on the molecular scale. The Si/Ti ratio of the oxide may be controlled easily by the composition of the starting precursors. Hydrolysis of the glycol modified derivative, (1A) by the Sol–Gel technique affords the desired homogenous titania–silica material, TiO₂·SiO₂ in nano-size while, the precursor (A) yields a non-stiochiometric silica doped titania material. However, pyrolysis of (A) yields nano-sized crystallites of TiO₂·SiO₂. All these materials were characterized by FTIR, powder XRD patterns, SEM images, and EDX analyses.     

Rapid In Vitro Production of Cloned Plants of <Emphasis Type="Italic">Uraria picta</Emphasis> (Jacq.) DC—A Rare Medicinal Herb in Long-Term Culture

An efficient in vitro process for rapid production of cloned plants of Uraria picta has been developed employing nodal stem segments taken from field-grown plants. Explants showed bud-break followed by regeneration of shoots with restricted growth within 12 days on modified Murashige and Skoog’s medium supplemented with 0.25 mg l^–1 each of 6-benzylaminopurine and indole-3-acetic acid and 25 mg l^-1 adenine sulfate. Normal growth of shoots with good proliferation rate was achieved by reducing the concentrations of 6-benzylaminopurine and indole-3-acetic acid to 0.1 mg l^-1 each and incorporating 0.5 mg l^-1 gibberellic acid in the medium in which, on an average, 19.6 shoots per explant were produced. Further, during successive subcultures, increased concentrations of adenine sulfate (50 mg l^-l) and gibberellic acid (2 mg l^-l) along with the addition of 20 mg l^-l  dl-tryptophan were found conducive to control the problem of necrosis of shoots. In this treatment, several “crops” of shoots were obtained from single culture by repeated subculturing of basal portion of stalk in long-term. Isolated shoots rooted 100% in 0.25 mg l^-1 indole-3-butyric acid. In vitro-raised plants after hardening in inorganic salt solution grew normally in soil and came to flowering. Genetic fidelity of in vitro-raised plants was ascertained by rapid amplified polymorphic DNA (RAPD) markers. Also, quantitative estimation of two isoflavonones in their root extracts further confirmed true-to-type nature of plantlets.     

Synthesis and characterization of glycol-modified vanadium(V) oxoisopropoxide and their oximato derivatives: sol–gel transformations of [VO(OPr i )3], [VO{OCH2CH2OCH2CH2O}{OPr i }] and [VO{OCH2CH2OCH2CH2O}{ON=C(CH3)(C4H3S-2)}] to vanadia

Reaction of [VO(OPr ⁱ )₃] (1) with [O(CH₂CH₂OH)₂] in 1:1 molar ratio in anhydrous benzene yield glycol-modified precursor, [VO{OCH₂CH₂OCH₂CH₂O}{OPr ⁱ }] (2). Further reactions of (2) with internally functionalized oximes in anhydrous benzene yield heteroleptic complexes of the type [VO{OCH₂CH₂OCH₂CH₂O}{ON=C(R)(Ar)}] (3–8) {where R=CH₃, Ar=C₄H₃O-2 (3), C₄H₃S-2 (4), C₅H₄N-2 (5); and when R=H, Ar=C₄H₃O-2 (6), C₄H₃S-2 (7), C₅H₄N-2 (8)}. All these derivatives have been characterized by elemental analyses, molecular weight measurements and spectroscopic techniques. The crysoscopic molecular weight measurement as well as FAB mass study suggests dimeric nature of (2). However, FAB mass spectrum of (4), and the crysoscopic molecular weight measurements of (3), (4), (5) and (6) indicate the monomeric behavior of the oximato derivatives (3–8). Hexa-coordination around vanadium(V) has been proposed for both monomeric and dimeric derivatives. Sol–gel transformations of (1), (2) or (4) to vanadia [(a), (b) or (c), respectively] have been carried out at low sintering temperature (600 °C). The XRD patterns of (a), (b) or (c) indicate formation of a single orthorhombic phase in all the three cases. The SEM images suggest grain like [for (a) and (b)] and rod like [for (c)] morphology of the crystallites. IR, Raman spectra as well as EDX analyses indicate formation of pure vanadia. Absorption spectra of the vanadia (b) and (c) suggest energy band gaps of 2.53 and 2.65 eV, respectively.     

Poly(β‐cyclodextrin)/Curcumin Self‐Assembly: A Novel Approach to Improve Curcumin Delivery and its Therapeutic Efficacy in Prostate Cancer Cells

A novel PCD/CUR self‐assembly approach for improved curcumin delivery to prostate cancer cells is described. The formation of PCD/CUR was confirmed using FTIR, DSC, TGA, and SEM/TEM, and their stability and solubility under physiological conditions was demonstrated. A mechanism for self‐assembly is proposed. Intracellular uptake of the self‐assemblies was studied by flow cytometry and immunofluorescence microscopy. The therapeutic efficacy was determined by cell proliferation and colony formation assays using C4‐2, DU145 and PC3 prostate cancer cells. The results suggest that the PCD/CUR formulation could be a useful system for improving curcumin delivery and its therapeutic efficacy in prostate cancer.