85416-36-0 Pentalenolactone F Spiro(oxirane-2,1'(2'H)-pentaleno(1,6a-c)pyran)-5'-carboxylic acid, 4',4'a,6'a,7',8',9'-hexahydro-8',8'-dimethyl-2'-oxo-, (1'R-(1'alpha,4'aalpha,6'abeta,9'aR*))-