Mupirocin is an alpha,beta-unsaturated ester resulting from the formal condensation of the alcoholic hydroxy group of 9-hydroxynonanoic acid with the carboxy group of (2E)-4-[(2S)-tetrahydro-2H-pyran-2-yl]-3-methylbut-2-enoic acid in which the tetrahydropyranyl ring is substituted at positions 3 and 4 by hydroxy groups and at position 5 by a {(2S,3S)-3-[(2S,3S)-3-hydroxybutan-2-yl]oxiran-2-yl}methyl group. Originally isolated from the Gram-negative bacterium Pseudomonas fluorescens, it is used as a topical antibiotic for the treatment of Gram-positive bacterial infections. It has a role as an antibacterial drug, a protein synthesis inhibitor and a bacterial metabolite. It is a monocarboxylic acid, a triol, an epoxide, a secondary alcohol, a member of oxanes and an alpha,beta-unsaturated carboxylic ester. It is a conjugate acid of a mupirocin(1-).
