into 2,3-dihydro-3-(3-hydroxypropyl)-7-isopropyl-3,4-dimethylnaphtho[2,3-b]furan-2-one (16). The alcohol 16 was further characterized as its acetate (17). After several attempts, the above C(1)–C(10) bond cleavage and B ring aromatization reaction were improved by use of concentrated sulfuric acid in refluxing acetic acid. Under these conditions, 2 gave 17 in 47% yield. Hydrolysis of 17 with hydrochloric
6-羟基-5βH-abieta-6,8,11,13-tetraen-18-oic acid 18,6-lactone (2) 与
硫酸氢钾在 220 °C 下融合得到双 [3-(2,3-dihydro -7-异丙基-3,
4-二甲基-2-氧代
萘并[2,3-b]
呋喃-3-基)丙基]醚(12),产率为37%,连同两种次要产物,产率为12%:2, 3-二氢-7-异丙基-3,4-二甲基-3-丙基
萘[2,3-b]
呋喃-2-酮和3-烯丙基-2,3-二氢-7-异丙基-3,4-
二甲基萘[ 2,3-b]
呋喃-2-一。在 160 °C 下用
对甲苯磺酸处理 12 得到 2,3-二氢-7-异丙基-3,4-二甲基-3-(3-
甲苯磺酰氧基丙基)
萘并[2,3-b]
呋喃-2-酮,将其转化为 2,3-二氢-3-(3-羟丙基)-7-异丙基-3,4-
二甲基萘并[2,3-b]
呋喃-2-酮 (16)。醇16进一步表征为其
乙酸酯(17)