Showing papers on "Nonactin published in 2011"

Solvent extraction of some divalent metal cations into nitrobenzene by using a synergistic mixture of strontium dicarbollylcobaltate and nonactin

Abstract: From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M2+(aq) + 1 · Sr2+(nb) ⇔ 1 · M2+(nb) + Sr2+(aq) taking place in the two-phase water–nitrobenzene system (M2+ = Mg2+, Ca2+, Ba2+, Cu2+, Zn2+, Pb2+, Mn2+, Ni2+; 1 = nonactin; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Moreover, the stability constants of the 1 · M2+ complexes in nitrobenzene saturated with water were calculated; they were found to increase in the following order: Mg2+, Mn2+ < Ba2+, Cu2+, Zn2+, Ni2+ < Sr2+ < Ca2+ < Pb2+.

Biotransformation of a biosynthetic intermediate mimic of nonactin by Streptomyces griseus

Abstract: Abstract A mimic of a plausible biosynthetic intermediate of bishomononactic acid, one of the monomers of macrotetrolide antibiotics (polynactin), was synthesized as a thiol ester. FAB-MS analysis showed that fermentation of polynactin producing Streptomyces griseus with the compound, afforded the unnatural polynactins containing bishomononactic acid(s).