A Metastable Semiquinone Molecular Switch Modulated by Ascorbate/O: A Study from a System Far-From-Equilibrium to Biological Assays in Mitochondria.

A molecular switch based on the metastable radical anion derived from a substituted heteroaryl quinone is described. Pyrrolyl quinone thiocyanate (PQ 9) showed an interaction with the fluoride anion that was visible to the naked eye and quantified by UV/vis and 1H and 13 C NMR. The metastable quinoid species formed by the interaction with F ("ON" state) showed a molecular switching effect autocontrolled by the presence of ascorbate ("OFF" state) and back to the "ON" state by an autooxidation process, measured by visible and UV/vis spectroscopy.

Differential Effect of 4-Benzo[] [1, 3]oxazines on the Proliferation of Breast Cancer Cell Lines.

Background: A family of 4-benzo[][1,3]oxazines were obtained from a group of -(2-alkynyl)aryl benzamides precursors via gold(I) catalysed chemoselective 6--dig C-O cyclization.

Method: The precursors and oxazines obtained were studied in breast cancer cell lines MCF-7, CAMA-1, HCC1954 and SKBR-3 with differential biological activity showing various degrees of inhibition with a notable effect for those that had an aryl substituted at C-2 of the molecules. 4-benzo[][1,3]oxazines showed an IC rating from 0.

Gold(I)-Catalyzed Synthesis of 4-Benzo[][1,3]oxazines and Biological Evaluation of Activity in Breast Cancer Cells.

The first gold(I)-catalyzed cycloisomerization procedure applied to the synthesis of substituted 4-benzo[][1,3]oxazines has been developed starting from -(2-alkynyl)aryl benzamides. The chemoselective oxygen cyclization via the 6--dig pathway yielded the observed heterocycles in modest to good chemical yields under very mild reaction conditions. The obtained oxazines were assayed on the breast cancer (BC)-derived cell lines MCF-7 and HCC1954 with differential biological activity.