Photodetachment of NO−2; experimental evidence for a new isomer

The relative cross section for the gas phase photodetachment of electrons has been determined for nitrite ions in the wavelength region 280–740 nm (4.43-1.68 eV). The vertical detachment energy for ONO^? has been determined to be ≈ 2.8 eV. Evidence is presented for a new isomer of NO^?₂.     

Total synthesis of citrafungin A

The antifungal natural product citrafungin A was synthesized using, as key steps, an asymmetric aldol reaction of a chiral oxazolidinone, diastereoselective alkylation of a chiral 1,3-dioxolan-2-one, semihydrogenation of an enyne, and selective methyl ester deprotection.     

Metal-specific allosteric activation and deactivation of a diamine

The reaction of a potentially tetradentate bis(pyridyl-thiazole) ligand with acetone is allosterically activated upon complexation with Cd(II) but deactivated by reaction with Cu(I), demonstrating metal-specific allosteric controlled reactivity.     

Solid-phase synthesis and stereochemical assignments of tenuecyclamides A-D employing heterocyclic amino acids derived from commercially available Fmoc alpha-amino acids

[reaction: see text] The solid-phase assembly of heterocyclic amino acids enabled the total synthesis of numerous diastereoisomers of tenuecyclamides A-D, establishing or correcting the stereochemistry of each natural product. This strategy provides a very efficient route to synthesize thiazole- and oxazole-containing macrolactams from heterocyclic amino acids that are readily prepared from Fmoc-alpha-amino acids. This methodology appears to be broadly applicable to the synthesis of natural product libraries incorporating unnatural heterocyclic amino acid residues for the purpose of drug discovery.