A new series of sodium cobalt oxyhydrates

We report a new series of sodium cobalt oxyhydrates that contains the same two dimensional building blocks as superconducting NaxCoO2.yH2O. The absence of superconductivity emphasises the importance of the CoO2 stacking arrangement on the resultant electronic properties.     

Autocatalytic formation of green heme: evidence for H2O2-dependent formation of a covalent methionine-heme linkage in ascorbate peroxidase

The mammalian heme peroxidases are distinguished from their plant and fungal counterparts by the fact that the heme group is covalently bound to the protein through ester links from glutamate and aspartate residues to the heme 1- and 5-methyl groups and, in the case of myeloperoxidase, through an additional sulfonium link from the Cbeta of the 2-vinyl group to a methionine residue. To duplicate the sulfonium link in myeloperoxidase and to obtain information on its mechanism of formation, we have engineered a methionine residue close to the 2-vinyl group in recombinant pea cytosolic ascorbate peroxidase (rpAPX) by replacement of Ser160 by Met (S160M variant). The S160M variant is isolated from Escherichia coli as apo-protein. Reconstitution of apo-S160M with exogenous heme gives a red protein (S160M(R)) which has UV-visible (lambda(max)/nm = 407, 511, 633) and steady-state kinetic (kcat = 156 +/- 7 s(-1), KM = 102 +/- 15 microM) properties that are analogous to those of rpAPX. The reaction of S160M(R) with H2O2 gives a green protein (S160M(G)). Electronic spectroscopy, mass spectrometry, and HPLC analyses are consistent with the formation of a covalent linkage between the methionine residue and the heme vinyl group in S160M(G). Single-wavelength and photodiode array stopped-flow kinetic analyses identify a transient Compound I species as a reaction intermediate. The results provide the first direct evidence that covalent heme linkage formation occurs as an H2O2-dependent process that involves Compound I formation. A mechanism that is consistent with the data is presented.     

Measurement of the relative branching fraction of upsilon(4S) to charged and neutral B-meson pairs

We analyze 9.7x10(6) B_B pairs recorded with the CLEO detector to determine the production ratio of charged to neutral B-meson pairs produced at the Upsilon(4S) resonance. We measure the rates for B0-->J/psiK((*)0) and B+-->J/psiK((*)+) decays and use the world-average B-meson lifetime ratio to extract the relative widths f(+-) / f(00) = gamma(Upsilon(4S)-->B+B-) / gamma(Upsilon(4S)-->B0 B-0)) = 1.04+/-0.07(stat)+/-0.04(syst). With the assumption that f(+-)+f(00) = 1, we obtain f(00) = 0.49+/-0.02(stat)+/-0.01(syst) and f(+-) = 0.51+/-0.02(stat)+/-0.01(syst). This production ratio and its uncertainty apply to all exclusive B-meson branching fractions measured at the Upsilon(4S) resonance.     

Trapping of radical intermediate in reaction of sulphonates with sodium iodide/zinc/dme. Total frontier orbital control of stereoselectivity in ring closure.

Reductive cyclization has been shown to accompany reduction on NaI/Zn/DME treatment of sulphonates of γ,δ- unsaturated alcohols. Stereoselectivity is due to FMO control with axial extension of SOMO of cyclohexyl radical playing a crucial role.     

SYNTHESIS OF NOVEL SULPHONAMIDES AND EVALUATION OF THEIR ANTIBACTERIAL EFFICACY

4-(4′-sulphanilyl)-1-phenyl pipearzine (2) has been prepared by ther reaction of N-acetyl sulphanilyl chloride (ASC) with 1-phenyl piperazine followed by the hydrolysis of the product by ethanolic HCl. The hydrolyze product on facile condensation reaction with aromatic aldehydes yields Schiff bases/anils/azomethines (3a–h). These anils on cyclo condensation reaction with chloro acetyl chloride and thio glycolic acid (mercapto acetic acid) yields 2-azetidinones and 4-thiazolidinones respectively. Biological screening of the prepared compounds have been screened on some strains of bacteria.