Direct macrolactonization of 3, 5-O-(3, 4-dimethoxybenzylidene)-9, 11-O-(2, 4, 6-trimethylbenzylidene)-(9S)-9-dihy-droeythronolide A seco-acid (3) with several reagents was examined under various conditions, and the Yamaguchi reagent (8) was found to be the most reactive and effective; treatment of 3 with 8 in the presence of a small amount of 4-dimethylaminopyridine and a large excess of triethylamine at room temperature gave almost quantitatively the corresponding 14-membered erythronolide A derivative (5).
在各种条件下,对3,5-O-(3,4-二甲氧基苄亚基)-9,11-O-(2,4,6-三甲基苄亚基)-(9S)-9-
二氢赤松素内酯 A 仲酸 (3) 与多种试剂的直接大环缩合进行了研究,发现山口试剂 (8) 反应性最强、效果最好;在室温下,在少量 4-二甲基
氨基吡啶和大量
三乙胺的存在下,用 8 处理 3,几乎可以定量得到相应的 14 成员
赤松素内酯 A 衍
生物 (5)。