commercial macrolide antibiotic fidaxomicin was synthesized in a highly convergent manner. Salient features of this synthesis include a β-selective noviosylation, a β-selective rhamnosylation, a ring-closing metathesis, a Suzuki coupling, and a vinylogous Mukaiyama aldol reaction. Careful choice of protecting groups and fine-tuning of the glycosylation reactions led to the first total synthesis of fidaxomicin
Synthesis and Biological Activity of Enantiomeric Pairs of 5-(Alk-2-enyl)thiolactomycin and 5-[(E)-Cycloalk-2-enylidenemethyl]thiolactomycin Congeners
作者:Kohei Ohata、Shiro Terashima
DOI:10.1248/cpb.57.920
日期:——
The title compounds were synthesized by the efficient route previously explored for the synthesis of enantiomeric pairs of thiolactomycin and its 3-demethyl derivative. These studies were carried out to prove the flexibility of the previously explored synthetic route to natural thiolactomycin (TLM) 1 and to examine the structure–activity relationship on the 5-position of 1. While all of the synthesized congeners lacked in vitro antibacterial activity, these studies led us to find 5-(alk-2-enyl)-TLM (ent-4d) which exhibits mammalian type I fatty acid synthase (FAS) inhibitory activity equal to that of C75, a potent inhibitor reported previously. It was also found that 5-[(E)-cycloalk-2-enylidenemethyl]-TLM (ent-5c) exhibited slightly less potent mammalian type I FAS inhibitory activity than C75.
标题化合物是通过之前探索的合成硫代霉素对映体及其 3-去甲基衍生物的高效路线合成的。虽然所有合成的同系物都缺乏体外抗菌活性,但这些研究使我们发现了 5-(alk-2-enyl)-TLM(ent-4d),它对哺乳动物 I 型脂肪酸合成酶(FAS)的抑制活性与之前报道的强效抑制剂 C75 相当。研究还发现,5-[(E)-环烷-2-亚烯基甲基]-TLM(ent-5c)对哺乳动物 I 型脂肪酸合成酶的抑制活性略低于 C75。
Total Synthesis of the Protected Aglycon of Fidaxomicin (Tiacumicin B, Lipiarmycin A3)
Fidaxomicin, also known as tiacumicinB or lipiarmycin A3, is a novel macrocyclic antibiotic that is used in hospitals for the treatment of Clostridium difficile infections. This natural product has also been shown to have excellent bactericidal activity against multidrug‐resistant Mycobacterium tuberculosis. In spite of its attractive biological activity, no total synthesis has been reported to date