1,5-(Epoxymethano)cyclopenta(c)pyran-3-carboxamide, 1,4a,5,7a-tetrahydro-5-hydroxy-8-oxo-, (1S-(1-alpha,4a-beta,5-beta,7a-beta))- 79127-35-8 Antibiotic XK 213 Echinosporin Echinosporin (Streptomyces) NSC 357683 XK 213