79405-82-6 NSC606843 Sonderianin Spiro[furan-3(2H),1'(2'H)-naphthalene]-5'-carboxylic acid, 5-(3-furanyl)-3',4,4',4'a,5,7',8',8'a-octahydro-2',4'a- dimethyl-2-oxo-, methyl ester, [1'.alpha.(S*),2'.alpha., 4'a.alpha.,8'a.beta.]-(-)-