Tripartilactam, a Cyclobutane-Bearing Tricyclic Lactam from a Streptomyces sp. in a Dung Beetle’s Brood Ball

Tripartilactam, a structurally unprecedented cyclobutane-bearing tricyclic lactam metabolite, was discovered from Streptomyces sp. isolated from a brood ball of the dung beetle, Copris tripartitus. The structure of this compound was elucidated by the combination of NMR, MS, UV, and IR spectroscopy and multistep chemical derivatization. Tripartilactam was evaluated as a Na(+)/K(+) ATPase inhibitor (IC(50) = 16.6 μg/mL).