93361-68-3 Pentalenolactone P Spiro(4H-cyclopropa(4,5)pentaleno(1,6a-c)pyran-1(2H),2'-oxirane)-5-carboxylic acid, 4a,6a,6b,7,7a,8-hexahydro-7a-methyl-2-oxo-, (1R-(1alpha,4aalpha,6abeta,6bbeta,7abeta,8aR*))-