The Na+ ion-assisted recognition of urea derivatives by BPX26C6 has allowed the construction of a redox-controllable [2]rotaxane-type molecular switch based on two originally very weakly interacting host/guest systems. Using NOBF4 to oxidize the triarylamine terminus into a corresponding radical cation attracted the macrocyclic component toward its adjacent carbamate station; subsequent additio...

A highly stereocontrolled, convergent total synthesis of kendomycin [(-)-TAN2162], an ansa-macrocyclic antibiotic, is reported. The key of the strategy is an unprecedented Tsuji-Trost macrocyclic etherification, followed by a transannular Claisen rearrangement to construct the 18-membered carbocyclic framework. The oxa-six- and five-membered rings were also stereoselectively constructed respect...

A couple of enantiomers of novel chiral macrocyclic imines based on R/S-camphor were asymmetrically synthesized. Through the chiral macrocyclic ligands, enantiomers of nickel(II) coordination compounds were obtained. The chirality of the ligand was transferred to the nickel atom upon coordination, leading to predetermined configuration. The chiral ligands and corresponding nickel coordination c...

This study was designated to clarify the influence of activation of porcine matured oocytes by calcium ionophore on in vitro development of the parthenotes. The follicular oocytes were matured, activated and cultured in North Carolina State University-23 (NCSU-23) medium supplemented with 10% porcine follicular fluid (pFF). The in vitro-matured oocytes were exposed to calcium ionophore at conce...

The processes involved in transport of K and Na by the carrier ionophores valinomycin and 18-crown-6 ether across cell membranes have been elucidated using quantum mechanical modelling: 1. Formation of the {ionophore-M} complex: desolvation (ΔGdesolv) of the central cavity of the ionophore, change in configurational energy TΔS, desolvation of the M(H2O)6-7 + 2. Desolvation of the {ionophore-M} ...

Ca2+ has been recently reported to be required for high rates of translational initiation in GH3 pituitary cells (Chin, K.-V., Cade, C., Brostrom, C.O., Galuska, E.M., and Brostrom, M.A. (1987) J. Biol. Chem. 262, 16509-16514). In the present investigation low concentrations of the Ca2+ ionophores, A23187 and ionomycin, were found to rapidly suppress the Ca2+-dependent component of protein synt...

BACKGROUND Due to the increasing industrial use of titanium compounds, its determination is the subject of considerable efforts. The ionophore or membrane active recognition is the most important component of any polymeric membrane sensor. The sensor's response depends on the ionophore and bonding between the ionophore and the target ion. Ionophores with molecule-sized dimensions containing cav...

Pial arterioles on the surface of the mouse brain were observed in vivo under a chamber with a glass window. When placed under the window, calcium ionophore, acetylcholine, and previously acidified sodium nitrite each dilated the arterioles. If the cyclooxygenase inhibitors indomethacin or acetylsalicylic acid were first placed in the chamber, subsequent dilation of the arterioles by calcium io...

synthesis and characterization of 6-(hydroxymethyl)-14, 16-dimethyl-13, 14, 16, 17-tetrahydro-6h-13, 17-epiminodibenzo [e, l] [1, 4] dioxacyclotridecin-15 (7h)-oneabstractnew 6-(hydroxymethyl)-14, 16-dimethyl-13, 14, 16, 17-tetrahydro-6h-13, 17-epiminodibenzo [e, l] [1, 4] dioxacyclotridecin-15 (7h)-one (2a) was synthesized in good yield by the petrenko–kritchenko reaction of 2, 2'-((3-hydroxyp...