13C NMR-study of flexibilide,an anti-inflammatory agent from a soft cora

Summary The use of¹³C spin-lattice relaxation measurements as a probe of structure in solution is illustrated for flexibilide. Analysis of quaternary carbon relaxation behaviour indicates that the structure in solution differs from the crystal structure. The effects of lanthanide shift and relaxation reagents on¹³C spectral parameters are also reported.Acknowledgment. We thank R.J. Wells, RRIMP, for helpful discussions.