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organic compounds
The present crystal structure determination established spiro[{3a,4,5,6,7,8,11,12,13,14,15,15a-dodecahydro-6,10,14-trimethyl-2-oxo-5,15-epoxy3H-cyclotetradeca[b]furan}]-3,3'-1'-pyrazoline]-6-yl acetate, C23H34N2O5, as a pyrazoline derivative of eunicin acetate. The spiro substitution of the pyrazoline ring causes elongation of the bonds within the lactone ring and also shortening of the carbonyl bond. The cembranolide skeleton is slightly more bent than that observed in the parent eunicin molecule.