We report the design and synthesis of a series of new cyclometalated iridium hydrides derived from the C-H bond activation of aromatic nitrones and the biological evaluation of these iridium hydrides as antitumor agents. The nitrone ligands are based on the structure of a popular antioxidant, α-phenyl-N-tert-butylnitrone (PBN). Compared to cisplatin, the iridium hydrides exhibit excellent antit...

Some new metal(II) dichloride complexes with the ligands substituted nitrones of the general formula [ML2Cl2], where M= Co(II), Ni(II), Cu(II), Zn(II) and Cd(II), L=OCH=CHCH=C-CH=N(O)C6H4X (X=H,p-CH3,CH3O,CH3CO,F,Cl,and Br) have been prepared and characterized by elemental analysis, IR,H,C NMR and Vis/Uv spectroscopy. The IR spectral data showed that the nitrone ligands coordinated with the met...

Strain-promoted alkyne-nitrone cycloadditon (SPANC) was optimized as a versatile strategy for dual functionalization of peptides and proteins. The usefulness of the dual labeling protocol is first exemplified by the simultaneous introduction of a chloroquine and a stearyl moiety, two endosomal escape-improving functional groups, into the cell-penetrating peptide hLF (human lactoferrin). Additio...

An approach to enantiopure hydroxylated 2H-1,2-oxazine derivatives is presented utilizing the [3 + 3] cyclisation of lithiated alkoxyallenes and an L-erythrose-derived N-glycosyl nitrone as precursors. This key step proceeded only with moderate diastereoselectivity, but allowed entry into both enantiomeric series of the resulting 3,6-dihydro-2H-1,2-oxazines. Their enol ether double bond was the...

It has been hypothesized that hyperthermia promotes oxygen-centered free radical formation in cells; however, to date there is no direct evidence of this heat-induced increase in oxygen free radical flux. Using electron paramagnetic resonance (EPR) spin trapping, we sought direct evidence for free radical generation during hyperthermia in intact, functioning cells. Rat intestinal epithelial cel...

The metal-catalyzed addition of aromatic substrates to electron deficient σand π-systems, commonly known as Friedel-Crafts alkylation,1 has long been established as a powerful strategy for C-C bond formation.2 Surprisingly, however, relatively few asymmetric catalytic protocols have been reported that exploit this venerable reaction manifold,3 despite the widespread availability of electron-ric...