Oxidation of 8-oxoerythrinan and 8-oxo-1, 7-cycloerythrinan derivatives with 2 mol eq of ceric ammonium nitrate in alcohols or acetic acid gave the corresponding 11β-alkoxy or acetoxy compounds in moderate yield. Thus, (±)-3, 3, 15, 16-tetramethoxy-1, 7-cycloerythrinan-2, 8-dione and (+)-erysotramidine gave the corresoponding 11β-methoxy and 11β-acetoxy derivatives on oxidation in methanol and in acetic acid, respectively. Those compounds were respectively converted into (±)-erythristemine and (+)-erythrartine in several steps, thus achieving the total synthesis of these alkaloids.
在醇或
乙酸中,使用2摩尔当量的
硝酸铈铵对8-氧代赤藓烷和8-氧代-1,7-环赤藓烷衍
生物进行氧化反应,以中等产率得到了相应的11β-烷氧基或
乙酸氧基化合物。因此,(±)-3,3,15,16-四甲氧基-1,7-环赤藓烷-2,8-二酮和(+)-赤藓酰胺分别在
甲醇和
乙酸中氧化,得到了相应的11β-甲氧基和11β-
乙酸氧基衍
生物。这些化合物分别经过几步反应,转化为(±)-赤藓碱和(+)-赤藓
石碱,从而实现了这些
生物碱的全合成。