A method of preparing (.+-.)-calanolide A, 1, a potent HIV reverse transcriptase inhibitor, from chromene 4 is provided. Useful intermediates for preparing (.+-.)-calanolide A and its derivatives are also provided. According to the disclosed method, chromene 4 intermediate was reacted with acetaldehyde diethyl acetal or paraldehyde in the presence of an acid catalyst with heating, or a two-step reaction including an aldol reaction with acetaldehyde and cyclization either under acidic conditions or neutral Mitsunobu conditions, to produce chromanone 7. Reduction of chromanone 7 with sodium borohydride, in the presence of cerium trichloride, produced (.+-.)-calanolide A. A method for resolving (.+-.)-calanolide A into its optically active forms by a chiral HPLC system or by enzymatic acylation and hydrolysis is also disclosed. Finally, a method for treating or preventing a viral infections using (.+-.)-calanolide or (-)-calanolide is provided.
提供了一种从
香豆素4制备(.+-.)-calanolide A、1,一种有效的HIV
反转录酶抑制剂的方法。还提供了制备(.+-.)-calanolide A及其衍
生物的有用中间体。根据公开的方法,将
香豆素4中间体与
乙二醇醚
乙醛或对
乙醛在酸催化剂存在下加热反应,或者在酸性条件或中性Mitsunobu条件下进行醛缩反应和环化的两步反应,制备出
香豆酮7。在
三氯化铈存在下,用氢化
钠还原
香豆酮7,制备出(.+-.)-calanolide A。还公开了通过手性HPLC系统或酶促酰化和
水解将(.+-.)-calanolide A分离成其光学活性形式的方法。最后,提供了使用(.+-.)-calanolide或(-)-calanolide治疗或预防病毒感染的方法。