201210-25-5Relevant articles and documents
Total Synthesis and Structural Establishment/Revision of Antibiotics A54145
Chen, Delin,Chow, Hoi Yee,Po, Kathy Hiu Laam,Ma, Wenjie,Leung, Emily Lok Yee,Sun, Zhenquan,Liu, Ming,Chen, Sheng,Li, Xuechen
, p. 5639 - 5644 (2019)
A54145 is a family of antibacterial cyclic lipodepsipeptides structurally resembling daptomycin. Since its discovery in 1990, only the ambiguous structures of the methoxy-aspartic acid (MeO-Asp) and the hydroxy-asparagine (HO-Asn) have been reported. We have developed efficient routes to obtain the fully protected l-MeO-Asp and l-HO-Asn building blocks compatible with Fmoc-SPPS, and a total synthesis of A54145 that enabled us to establish its structure, consisting of l-3S-HO-Asn and l-3R-MeO-Asp, revising the wrongly proposed structure of l-3S-MeO-Asp.
The role of phosphopeptides in the mineralisation of silica
Daus, Fabian,Geyer, Armin,Hampp, Norbert,Pfeifer, Erik,Seipp, Kevin
supporting information, p. 700 - 706 (2020/02/11)
We investigated the silicification activity of hyperphosphorylated peptides in combination with long-chain polyamines (LCPA). The bioinspired in vitro silicification experiments with peptides containing different amounts of phosphorylated serines showed structure-activity dependence by altering the amount and morphology of the silica precipitate. Our study provides an explanation for the considerable metabolic role of diatoms in the synthesis of hyperphosphorylated poly-cationic peptides such as natSil-1A1. The efficient late-stage phosphorylation of peptides yielded a synthetic heptaphosphopeptide whose silicification properties resemble those of natSil-1A1. As opposed to this, unphosphorylated poly-cationic peptides or LCPA require concentrations above 1 mM for silicification. Hyperphosphorylated peptides showed a linear dependence between the amount of dissolved peptides and the amount of precipitated silica in the concentration range below 1 mM. Under mildly acidic conditions and short precipitation times, the concentration of the added LCPA determined the size of the silica spheres.
Sterically biased 3,3-sigmatropic rearrangement of azides: Efficient preparation of nonracemic α-amino acids and heterocycles
Gagnon, David,Lauzon, Sophie,Godbout, Cedrickx,Spino, Claude
, p. 4769 - 4771 (2007/10/03)
(Chemical Equation Presented) Homochiral α-amino acids, heterocycles, and carbocycles are efficiently constructed via a short sequence of reactions starting from the chiral auxiliary p-menthane-3-carboxaldehyde. The key feature of the sequence is a highly selective tandem Mitsunobu/3,3-sigmatropic rearrangement of hydrazoic acid that procures enantiomerically enriched allylic azides. The sequence is either terminated by oxidative cleavage to provide amino acids or by ring-closing metathesis to provide heterocycles or carbocycles bearing nitrogen.