of fluocinolone acetonide with combination of bio-fermentation was developed from 21-acetyloxy-17α-hydroxy-4,9(11)-diene-3,20-dione (1a). Process of the 6α and 9α fluorination steps was studied, and it was observed that the stereoselectivity of 6α fluorination is highly substrate dependent. After an extensive screening on the fluorinating reagents and activation reagents, 6α-F was introduced in 85%
从 21-乙酰氧基-17α-羟基-4,9(11)-二烯-3,20-二酮 (1a) 开发了一种高效、改进的
氟轻松与
生物发酵相结合的合成路线。研究了 6α 和 9α
氟化步骤的过程,观察到 6α
氟化的立体选择性高度依赖于底物。在对
氟化试剂和活化试剂进行广泛筛选后,6α-F 以 85% 的收率和 98.9% 的立体选择性引入。代替 HF 气体,在 9α
氟化步骤中应用 HF
水溶液,以 89% 的收率提供所需的产物。从 1a 开始,
氟轻松分 9 个步骤制备,总产率为 38.5%。