Conformational analysis of a model for the trans-fused FGH ether rings in brevetoxin A.
We have applied the Low Mode:Monte Carlo (LM:MC) conformational search method to an investigation of the low energy structures for 3R,4aS,7aR,11aS,12aR)-11a-methyl-3-phenyldecahydro-1H-[1,3]dioxino[5,4-b]pyrano[2,3-g]oxocine, 3, a model for the FGH rings in brevetoxin A, a potent marine toxin. Searches performed using a variety of classical force field-solvent combinations yielded ensembles containing between 30 and 60 structures with the central G-ring adopting the crown, twist-crown, boat-chair, and boat conformations. The lowest energy structure depended on the force field-solvent treatment, and the twist-crown and boat-chair conformers were typically lowest in energy. B3LYP/6-31G** geometry optimizations using the SCRF continuum solvent model confirmed these structures but indicated that the crown was the energetically preferred conformer with the boat-chair lying within 1.4 kcal/mol.
Department of Chemistry, Gottwald Center for the Sciences, University of Richmond, Richmond, Virginia 23173, USA.
Evan B
EB
Wang
Carol A
CA
Parish
D004988:Ethers, Cyclic / Q000737:chemistry*; D008387:Marine Toxins / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D035964:Oxocins / Q000737:chemistry*; D011789:Quantum Theory; D012997:Solvents / Q000737:chemistry; D000095702:Polyether Toxins
D004988:Ethers, Cyclic; D008387:Marine Toxins; D035964:Oxocins; D012997:Solvents; C076262:Brevetoxin A; D000095702:Polyether Toxins