CRYSTAL STRUCTURE OF NEW BRIARAN DITERPENES FROM THE FORMOSAN GOGRONIAN BRIAREUM SPECIMEN

Tsong-Jen Lee

X-Ray Lab. National Tsing Hua University, Hsinchu, Taiwan e-mail: tjlee@phys.nthu.edu.tw

Three new briaran diterpenes, 2Beta-acetoxy-2-(debutyryloxy)stecholide E, 9-deacetylstylatulide lactone, and 4Beta-acetoxy-9-deacetylstylatulide lactone, and two known diterpenes, brianthein W and 9-deacetylbriareolide H, have been isolated from a Briareum sp. of gorgonian. Their ctystal structures have been determined by X-Ray method. The structures and relative stereochimistry of these compounds were determinded by spectroscopic and chemical methods. Diterpenes 2-4 and the corresponding 9-acetyl derivatives 6, 7, and 12 exhibited cytotoxicity toward various cancer cell lines.