Synonyms: Pentanedioicacid,3-[1'-(3-furanyl)-3',6',7',7'a-tetrahydro-2,5,7'a-trimethyl-3,3'-dioxospiro[4-cyclopentene-1,5'(1'H)-cyclopenta[c]pyran]-2-yl]-2,2-dimethyl-,dimethyl ester (9CI); Spiro[cyclopentane-1,5'(1'H)-cyclopenta[c]pyran],pentanedioic acid deriv.; Guyanin