Approaches to the Synthesis of Some Tyrosine-Derived Marine Sponge Metabolites: Synthesis of Verongamine and Purealidin N
作者:Todd R. Boehlow、J. Jonathan Harburn、Christopher D. Spilling
DOI:10.1021/jo010015v
日期:2001.5.1
oxime (8) in high yield. Controlled bromination of the aromatic ring gave the monobromo oxime (9), the dibromo oxime (10), or the spiroisoxazoline (11) depending upon reaction conditions. Synthesis of the known metabolite verongamine (15) was achieved by oxidation of O-methyl bromotyrosine methyl ester and amidation of the resulting oxime ester (14) with histamine. The mono- and di-bromotyrosine oxime derivatives
用乙醇中的Na(2)WO(4)/ H(2)O(2),丙酮中的二甲基二环氧乙烷或乙醇中的甲基三氧tri / H(2)O(2)氧化酪氨酸乙酯(7)得到相应的酪氨酸肟(8)高产。根据反应条件,芳香环的受控溴化得到一溴肟(9),二溴肟(10)或螺异恶唑啉(11)。通过氧化O-甲基溴酪氨酸甲酯并用组胺酰胺化所得肟酯(14),可以合成已知的代谢产物verongamine(15)。通过酯的碱水解和酸催化的脱羧作用,将单和二溴酪氨酸肟衍生物(9和10)进一步转化为天然腈(16和17)。二溴苯甲醛(20b)与膦酸酯(18)的Wadsworth-Emmons烯烃化反应得到丙酮酸甲硅烷基醚(21b)。脱保护并原位生成肟,得到肟酯(23b)。尝试纯化丙酮酸酯会导致高醛缩合,生成丁烯内酯(22)。肟酯(23b)与组胺的酰胺化反应,然后MOM醚的脱保护反应,首次合成了Purealidin N(28)。用与聚合物结合的