Cytosporone E: racemic synthesis and preliminary antibacterial testing

Cytosporone E was synthesized using the Meyers ortho-alkylation of a chiral aromatic oxazoline as the key step to form the phthalide backbone. Antibacterial testing demonstrates activity against Gram-positive bacteria and not Gram-negative bacteria. The antibiotic cytosporone E (isolated from the broth of the endophytic fungi CR 200 ( Cytospora sp.) and CR 146 ( Diaporthe sp.)) was synthesized as a racemic mixture. The key step in the synthesis is the Meyers ortho-alkylation of a chiral aromatic oxazoline. Preliminary antibiotic activity shows antibiosis against Gram-positive bacteria but not Gram-negative bacteria as previously reported.