Ultraviolet irradiation of (1R,3S,4S,5S,10R,11R)-1-acetyloxy-7-oxolongipin-8-ene (6), prepared from longipinene diesters isolated from Stevia salicifolia, afforded the new quirogane (7) and prenopsane (8) derivatives, as the major products, together with the minor secondary photoproduct (1R,3R,5R,8S,11S)-1-acetyloxy-7-oxopatzcuar-9-ene (9), which possesses a novel tricyclic sesquiterpene skeleton. The stereostructures
用从甜叶菊中分离出的长二烯二酯制备的(1R,3S,4S,5S,10R,11R)-1-乙酰氧基-7-氧代隆基-8-烯(6)进行紫外线照射,得到了新的基烷(7)和前
正庚烷(8)作为主要产物的衍
生物,以及次要的次要光产物(1R,3R,5R,8S,11S)-1-乙酰氧基-7-氧杂帕茨酸-9-烯(9),具有新的
三环倍半萜骨架。新化合物7-9的立体结构主要通过NMR技术确定,包括COSY,HSQC,HMBC和NOESY,并结合通过密度泛函理论计算获得的分子模型。提出了解释观察到的转化的反应机理。