【摘要】 从D-缬氨酸,L-苏氨酸,L-异亮氨酸出发,合成了海洋环肽Ascidiacyclamide,其中D-(缬)噻唑氨基酸由亚胺酯方法合成,最后用DPPA环二聚得最终产物。更多还原

【Abstract】 Ascidia cyclamide,isolated from an unidentified species of ascidian col-lected in Australia,is a cytotoxic cyclopeptide containing thiazole and oxazo-line amino acids.We have Synthesized it from D-valine,L-threoine andL-isoleucine.D-(val)Thiazole amino acid(1)was prepared by imino method from D-valine.2 was obtained by Boc-cleavage of 1.Coupling of Boc-L-Thr with 2 was achieved by DCC/HOBT method to produce the dipeptide (3)·Deprotection of 3 gave 4.Condensation of 4 with imino ether yieled oxazoline intermediate(9)in 74% yield.Deprotection and cyclodimerization of 9 with DPPA produced Ascidiacyclamide.更多还原