Franzyk H, Jensen SR, Thale Z, Olsen CE
Department of Organic Chemistry, The Technical University of Denmark, DK-2800 Lyngby, Denmark, and Department of Chemistry, The Royal Agricultural and Veterinary University, DK-1871 Frederiksberg C, Denmark.
J Nat Prod. 1999 Feb;62(2):275-8. doi: 10.1021/np980358x.
Treatment of the iridoid glucoside antirrhinoside (1) with pyridinium chloride in dimethylformamide gave rise to the two possible trans-halohydrins, linarioside (4) and isolinarioside (5). Pyridinium bromide gave the two analogous bromohydrins. It is shown that the iridoid glucosides 8-epi-muralioside from Linaria arcusangeli and 7,8-epi-antirrhinoside from Linaria dalmatica are both identical with isolinarioside, and therefore, these names are redundant. The structure of muralioside isolated from Cymbalaria muralis is revised to that of its 8-epimer (8), while the structure of an isomeric, new iridoid glucoside from Paulownia tomentosa has been elucidated to be 7beta-hydroxyharpagide (3), the structure originally assigned to 8. In addition, 7alpha-hydroxyharpagide (2), the known product from the base-catalyzed hydrolytic opening of 1, has been isolated from Antirrhinum majus and thus shown to be a natural product.
在二甲基甲酰胺中用氯化吡啶处理环烯醚萜苷抗坏血酸苷（1），得到两种可能的反式卤代醇，即亚麻苷（4）和异亚麻苷（5）。溴化吡啶得到两种类似的溴代醇。结果表明，来自弧花柳穿鱼的环烯醚萜苷8-表-穆拉苷和来自达尔马提亚柳穿鱼的7,8-表-抗坏血酸苷都与异亚麻苷相同，因此，这些名称是多余的。从墙藓中分离出的穆拉苷的结构修订为其8-表异构体（8）的结构，而从毛泡桐中分离出的一种异构的新环烯醚萜苷的结构已被阐明为7β-羟基哈帕苷（3），该结构最初被指定为8。此外，7α-羟基哈帕苷（2），即1经碱催化水解开环得到的已知产物，已从金鱼草中分离出来，因此表明它是一种天然产物。
