10.1039/c2ob25685a
The research focuses on the total synthesis of piperidine alkaloids, specifically (+)-241D, isosolenopsin, and isosolenopsin A, which are derived from D-alanine. The study employs a gold-catalyzed cyclization as the key step to access the chiral pyridinone intermediates, which are crucial for the synthesis of these alkaloids. The synthesis involves multiple steps, including the preparation of chiral synthons, gold-catalyzed intramolecular cyclization, and stereoselective reductions. The experiments utilized various reactants such as N-Boc-D-alanine, undecyne, BuLi, PPh3AuCl, and AgSbF6, among others, and employed techniques like Arndt–Eistert homologation and catalytic hydrogenation. The synthesized compounds were analyzed using spectroscopic methods (1H and 13C NMR, IR, and HRMS) and optical rotation measurements to confirm their structures and enantiomeric purity.
10.1021/jm00121a030
The research focuses on the synthesis and evaluation of potential inhibitors targeting D-alanine:D-alanine ligase (ADP forming), an enzyme involved in bacterial peptidoglycan biosynthesis. The purpose was to design novel antibacterial agents by inhibiting this key enzyme, using tabtoxinine, a known inhibitor of glutamine synthetase, as a model. The study synthesized and tested P-lactams 9R and 9S as potential precursors of a D-alanyl phosphate mimic. The conclusions drawn from the research were that lactams 9R and 9S did not inhibit D-alanine:D-alanine ligase or exhibit antibacterial activity, suggesting that the mechanism of the amide-bond-forming step or the binding geometry of the transition state for this step may differ from that of glutamine synthetase. The research also highlighted the need for further investigation into the design and synthesis of more effective inhibitors targeting D-alanyl phosphate.
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