31501-48-1 Antibiotic PA-132 Arenaemycin E Arenemycine NSC 136036 PA-132 Pentalenolactone Spiro(oxirane-2,1'(2H)-pentaleno(1,6a-c)pyran)-5'-carboxylic acid, 4',4'a,6'a,7'-tetrahydro-7',8'-dimethyl-2'-oxo-, (1'R-(1'-alpha,4'a-alpha,6'a-beta,7'-alpha,9'aS*))-