The synthesis and chemistry of a simplified, functional analogue of neocarzinostatin chromophore: identification of an intramolecular 1,5-hydrogen atom

Efficient asymmetric synthesis of the vasopeptidase inhibitor BMS-189921

[reaction: see text] An efficient asymmetric synthesis of the vasopeptidase inhibitor BMS-189921 was accomplished. Two short enantioselective syntheses of the common key intermediate (S)-alpha-aminoazepinone 6b were developed. Olefin 3 was converted to 6b via asymmetric hydrogenation. Alternatively, enyne 12 was converted to racemic alpha-aminoazepinone 15b, which was transformed to 6b by a practical dynamic resolution.

Organometallic photonucleases: a novel class of DNA-cleaving agents

The first demonstration of DNA cleavage by an organic radical generated via homolysis of a metal-alkyl bond in a Cp-metal complex is presented. Irradiation of CpW(CO)3CH3 (1.5 molecules/base pair) produced methyl radical, giving single-strand cleavage of pBR322 DNA. This process was inhibited by the general radical trap cysteine and by TEMPO, which traps carbon radicals but not oxygen-centered radicals.