Further search for selectivity of positron annihilation in the skin and cancerous systems

Positronium annihilation lifetime (PAL) spectroscopy and Doppler broadening energy spectra (DBES) have been used to search for selectivity and sensitivity for cancerous skin samples with and without cancer. This study is to further explore the melanoma cancerous system and other different types of skin samples. We found that the S parameter in melanoma skin samples cut at 0.39 mm depth from the same patient's skin is smaller than near the skin surface. However in 10 melanoma samples from different patients, the S parameters vary significantly. Similarly, among 10 normal skin samples without cancer, the S parameters also vary largely among different patients. To understand the sensitivity of PAS as a tool to detect cancer formation at the early stage, we propose a controlled and systematic study of in vivo experiments using UV-induced cancer skin from living animals.     

Synthesis and biological evaluation of some new class of benzothiazole–pyrazole ligands containing arene ruthenium,rhodium and iridium complexes

Transition Metal Chemistry - Metal complexes 1–9 have been synthesized by reacting the benzothiazole–pyrazole derivative ligands (L1, L2 and L3) with the metal precursors of ruthenium...     

Preparation of self-assembled porous flower-like nanostructured magnetite (Fe3O4) electrode material for supercapacitor application

Journal of Solid State Electrochemistry - Nanostructured electrode materials for supercapacitors have attracted research interest due to their high power density and long cycle life. Herein, porous...     

Water Soluble Nickel – metformin ternary complexes: Thermal,DNA binding and molecular docking studies

The Nickel (II) complexes [Ni(Cl)₂(metf)(o-phen)] (1), [Ni(Cl)₂(metf)(opda)] (2) , [Ni(Cl)₂(metf)(en)] (3) , [Ni(Cl)₂(metf)(2,2'-bipy)] (4) , (metf = metformin, o-phen = ortho-phenanthroline, opda = ortho-phenylenediamine, en = ethylenediamine, 2–2′ bipy = 2–2′ bipyridyl) were synthesized and characterized using LC–MS, elemental analysis, molar conductance measurements, TGA-DTA, IR spectroscopy, magnetic moment measurements and electronic spectroscopy. The central Ni²⁺ was found to be in octahedral geometry. The DNA interaction of these complexes have been studied by UV–visible absorption studies, fluorescence emission technique and viscosity measurement. The complexes showed absorption hyperchromism in UV–visible spectra with calf thymus DNA. The binding constants from UV–visible absorption studies were 7.42 × 10⁴, 0.74 × 10⁴, 3.19 × 10⁴, 5.9 × 10⁴ M⁻¹ for 1 , 2 , 3 and 4 , respectively and Stern-Volmer quenching constants from fluorescence studies were 0.16, 0.41, 0.23, 0.18, respectively. Viscosity measurements revealed that the binding of the complexes with DNA could be surface binding, mainly due to groove binding. The highest DNA cleavage activity of the complexes is recorded for complex 1 . The complexes were docked in to B-DNA sequence, 5′(D*AP*CP*CP*GP*AP*CP* GP*TP*CP*GP*GP*T)-3′ retrieved from protein data bank (PDB ID: 423D), using Discovery Studio 2.1 software. C Docker Intectraction energy of 1 , 2 , 3 and 4 complexes is 32.027, 31.427, 35.393 and 30.521 respectively. The highest docking score is seen for complex 3 .     

Enantioseparation of DPP-4 Inhibitors on Immobilized Crown Ether-Based Chiral Stationary Phase

A group of DPP-4 inhibitors such as alogliptin, linagliptin and saxagliptin were selected for enantioseparation for this study. Crown ether columns contain a chiral crown ether ring as a chiral selector is suitable for the compounds having primary amino groups. Since the selected compounds contain free amino groups, a crown ether column was selected for enantiomeric separation of dipeptidyl peptidase-4 inhibitors. Dipeptidyl peptidase-4 inhibitors are a class of oral hypoglycemics that block dipeptidyl peptidase-4 enzyme and can be used to treat diabetes mellitus type 2. A sensitive HPLC method was developed to separate the enantiomers of each dipeptidyl peptidase-4 inhibitor. Effects of various parameters such as type of solvents, selection of additives, effect of pH and column temperature on chromatographic results were studied. The optimal conditions for the chiral separation of dipeptidyl peptidase-4 inhibitors without any derivatization were investigated.     

Synthesis and molecular structure analysis of venlafaxine intermediate and its analog

1-(cyano-(4-methoxyphenyl) methyl cyclohexanol(2), C₂₄H₃₂N₂O₂, a Venlafaxine intermediate is found to crystallize in both monoclinic(2a) and orthorhombic(2b) crystal systems. The form2a crystallizes in the space groupC2/c with the cell parametersa = 23.506(3),b = 5.550(3),c = 23.192(3), and β = 115.116(2)^∘.2b crystallizes in space groupP2₁2₁2₁ with cell parametersa = 5.7850(6),b = 11.2680(6), andc = 20.6730(19). The intermolecular hydrogen bonding in the case of the monoclinic polymorph leads to the formation of dimer. The synthesis, characterization, and crystal structure studies of Venlafaxine analog 1-[2-1-(4-dimethylamino-phenyl)-ethylideneamino]-1-(4-methoxy-phenyl)-ethyl]-cyclohexanol(4) is reported.4 crystallizes inP―1 space group with cell parametersa = 10.801(7),b = 12.078(7),c = 9.928(5), α = 96.12(5)^∘, β = 110.49(5)^∘, and γ = 112.42(6)^∘.     

An efficient copper-aluminum hydrotalcite catalyst for asymmetric hydrosilylation of ketones at room temperature

A catalyst system consisting of a copper-aluminum hydrotalcite-chiral diphosphine ligand effects asymmetric hydrosilylation of several ketones, using polymethylhydrosiloxane (PMHS) as the stoichiometric reducing agent at room temperature, with moderate-to-excellent enantioselectivities. The catalyst is recovered by simple centrifugation, and the efficiency of the catalyst remains almost unaltered even after several cycles.     

Chiral ionic liquid-catalyzed Biginelli reaction: stereoselective synthesis of polyfunctionalized perhydropyrimidines

A chiral ionic liquid-catalyzed, efficient and unprecedented version of the Biginelli reaction using new variants of its active methylene component, viz. 2-phenyl-1,3-oxazol-5-one/2-methyl-2-phenyl-1,3-oxathiolan-5-one, with aromatic aldehydes and urea/thiourea enantio- and diastereoselectively, yields 5-amino-/mercaptoperhydropyrimidines. This three-component domino cyclocondensation reaction is effected via ring transformation of an isolable intermediate in a one-pot procedure.     

Direct asymmetric aldol reactions catalyzed by nanocrystalline copper(II) oxide

The direct asymmetric aldol reactions of aromatic and heteroaromatic aldehydes with acetone to afford chiral β-hydroxy carbonyl compounds in good yields and good to moderate enantioselectivities are realized using nanocrystalline copper(II) oxide in the presence of (1S,2S)-(−)-1,2-diphenylethylenediamine at −30 °C. The catalyst can be reused for four cycles with consistent activity and enantioselectivity.