(2R)-3-[(2S,6R,8S,11R)-2-[(E,1R)-3-[(2S,2&primeR,4R,4aS,6R,8aR)-4-Hydroxy-2-[(1S,3S)-1-hydroxy-3-[(2S,3R,6S)-3-methyl-1,7-dioxaspiro[5.5]undecan-2-yl]butyl]-3-methylene-spiro[4a,7,8,8a-tetrahydro-4H-pyrano[2,3-e]pyran-6,5'-tetrahydrofuran]-2'-yl]-1-methyl-prop-2-enyl]-11-hydroxy-4-methyl-1,7-dioxaspiro[5.5]undec-4-en-8-yl]-2-hydroxy-2-methyl-propanoic Acid; Spiro[furan-2(3H),2'(3'H)-pyrano[3,2-b]pyran], acanthifolicin deriv.; 35-Demethyl-DTX 1; 35-Demethyldinophysistoxin 1; NSC 677083