抄録
The molecular structure of spathulin (1a), a highly oxygenated pseudoguaianolide isolated from Gaillardia grandiflora has been established by a three dimensional X-ray crystallographic analysis of diacetylspathulin (1b). The space group of the crystal of 1b is P212121 and the dimensions of the cell with z=4 are a=9.6976 (3), b=26.968 (2), c=8.9288 (3) Å. The structure of the crystal was refined to R=0.05. The conformation of spathulin (1a) was estimated to be similar to that of pulchellin (2a), namely bis-deacetoxyspathulin except some differences particularly at C (6) and C (9), when the conformation of the pseudoguaianolide skeleton in 1b is compared with that in 11, 13-dibromopulchellin (2b).
