Impact of mono- and disubstitution on the colorimetric dynamic covalent switching chalcone/flavanone scaffold

The impact of substitution on a novel colorimetric dynamic covalent switching scaffold was investigated using UV/Vis and NMR spectroscopy.

Palladium-catalyzed ortho-CH-bond oxygenation of aromatic ketones

A palladium-catalyzed C((sp2))-H bond oxygenation reaction is described. This protocol represents the first example of a C-H bond cleavage/C-O bond formation sequence, by employing a ketone moiety as the directing group. With this new catalytic method, a variety of ortho-acylphenols can be easily accessed from arylketones.

A two step synthesis of BzR/GABAergic active flavones via a Wacker-related oxidation

A general route for the synthesis of biologically important flavones is reported via a two step sequence employing a catalytic Wacker-Cook oxidation4b as the key step.

Structural characterization and isomer differentiation of chalcones by electrospray ionization tandem mass spectrometry

A series of chalcones were characterized by electrospray ionization tandem mass spectrometry (MS(n)). Several ionization modes were evaluated, including protonation, deprotonation and metal complexation, with metal complexation being the most efficient. Collision-activated dissociation (CAD) was used to characterize the structures, and losses commonly observed include H(2), H(2)O, CO and CO(2), in addition to methyl radicals for the methoxy-containing chalcones. CAD of the metal complexes, especially [Co(II) (chalcone-H) 2,2'-bipyridine](+), allowed the most effective differentiation of the isomeric chalcones with several diagnostic fragment ions appearing upon activation of the metal complexes. MS(n) experiments were performed to support identification of some fragment ions and to verify the proposed fragmentation pathways. In several cases, MS(n) indicated that specific neutral losses occurred by stepwise pathways, such as the neutral loss of 44 u as CH3* and HCO*, or CH(4) and CO, in addition to CO(2).