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Sulfur substituted 3-vinylpyrrole 10 was prepared from 3-thio-acetylpyrrole 9 by alkylation with alkyl halide in the presence of propylene oxide. Functionalized 4-alkylthioindoles were made by Diels-Alder reaction of the 3-vinylpyrrole 10 with dienophiles. Chuangxinmycin analogues were synthesized by using some of the functionalized 4-alkylthioindoles as key intermediates.

The Stille coupling reaction of stannylindole 12 with 4-iodoimidazole 13 (or 24) in the presence of PdCl2(PPh3)2 gave the corresponding indole–imidazole coupling product 14 (or 25), thereby affording a new synthetic approach to the alkaloid granulatimide (7), isolated from the Brazilian ascidian Didemnum granulatum, as well as its structural analogues, 10-methylgranulatimide (23), 17-methylgranulatimide (30), 10,17-dimethylgranulatimide (31).

4-Pyridone derivatives were identified as potent inhibitors of FabI, the enoyl-acyl carrier protein reductase in Escherichia coli and Staphylococcus aureus. 1-Substituted derivatives of a hit compound exhibited potent antibacterial activities against S. aureus. Target specificity of 4-pyridone derivatives was confirmed by the strong inhibition of lipid synthesis in macromolecular biosynthesis assay and also by the reduced antimicrobial activity against triclosan-resistant S. aureus isolates possessing a point mutation (Ala95Val) in FabI. Two 4-pyridone compounds exhibited strong antibacterial activities against 30 clinical isolates of methicillin-resistant S. aureus (MRSA) with MIC(90) of 0.5 and 2 mug/ml, respectively. Moreover, they retained activity against S. aureus with a mutation affecting FabI residue 204, which was recently found to be associated with triclosan resistance in clinical isolates of S. aureus. In conclusion, we have identified a novel chemical series, 4-pyridone derivatives, as specific inhibitors of FabI with potent antibacterial activity against S. aureus.