10.1248/cpb.24.2629
The research focused on the synthesis and antibacterial activities of 7a-methoxy-7-[2-(substituted thio)acetamido]cephalosporin derivatives. The purpose was to develop more active cephalosporin derivatives by nucleophilic displacement of the halogen atom of 7β-(2-halogenoacetamido)-7-methoxy cephalosporanic acid derivatives with various mercapto compounds. The study concluded that the synthesized compounds, particularly those with a five-membered heterocyclic ring in the acylamido group, exhibited potent antibacterial activities, with compound (6) showing activities comparable to the semi-synthetic antibiotic cefoxitin and superior to cephalothin against gram-negative bacteria. Key chemicals used in the process included cephamycin C, tert-butoxycarbonyl azide, diphenyldiazomethane, chloroacetyl chloride, bis(trimethylsilyl)trifluoroacetamide, and various mercapto compounds for the nucleophilic displacement reaction.
10.1016/j.tetlet.2013.03.022
The research focuses on the synthesis of the naphthoquinone core of novel ansamycins, such as hygrocins A–B and divergolides C–D, which are biologically important macrolides derived from actinomycetes and exhibit antimicrobial and anti-cancer activities. The study aims to develop a facile and cost-effective synthetic route starting from the inexpensive 2-hydroxy-3-methylbenzoic acid, utilizing naphthalenic synthon for further elaboration of the ansabridge via C5–C6 bond formation. The researchers employed a commercially available sterically demanding organomagnesium reagent as a model ansa chain and successfully converted the resulting alcohol to the naphthoquinone fragment in one pot. The synthesis route is amenable to large-scale production and sets the stage for the total synthesis of these biologically important novel ansamycins.
Xn
