(1'S,6'R)-7-Chloro-2',4,6-trimethoxy-6'-methyl-spiro[benzofuran-2(3H),1'-[2]cyclohexene]-3,4'-dione; Spiro[benzofuran-2(3H),1'-[2]cyclohexene]-3,4'-dione, 7-chloro-2',4,6-trimethoxy-6'-methyl-, (1'S-trans)-; 7-Chloro-2′,4,6-trimethoxy-6′β-methylspiro[benzofuran-2(3H),1′-[2]cyclohexene]-3,4′-dione (USP)