Studies on Digitalis Glycosides. XII. Structures of Digipronin and Digiprogenin.
作者:Daisuke Satoh
DOI:10.1248/cpb.10.43
日期:——
Digipronin, a digitanol glycoside, and its aglycone, γ-digiprogenin, were respectively converted to isodigipronin and its aglycone, α-digiprogenin, by treatment with dilute alkali or acid. On refluxing with acid, α-digiprogenin lost an element of water and formed β-digiprogenin. The structure of the ⊿4-3-oxo compound, obtained from β-digiprogenin by reduction with acetic acid and zinc dust followed by Oppenauer oxidation, was established as 14β, 17α-pregn-4-ene-3, 11, 15, 20-tetrone by comparison with the product of isomerization of pregn-4-ene-3, 11, 15, 20-tetrone with alkali or acid. Consequently, the structure of β-digiprogenin was presumed as 3β-hydroxy-14β-pregna-5, 16-diene-11, 15, 20-trione and the tertiary hydroxyl group in α-and γ-digiprogenin would be located at 17-position. In view of the stability of α-digiprogenin to dilute alkali or acid and its negative contribution to optical rotation compared to γ-digiprogenin, it would be appropriate to give the structure of 3β, 17α-dihydroxy-14β-pregn-5-ene-11, 15, 20-trione and 3β, 17α-dihydroxypregn-5-ene-11, 15, 20-trione to α-and γ-digiprogenin, respectively. Digipronin is a monodigitaloside of γ-digiprogenin.
通过稀碱或稀酸的处理,地吉孕宁(地吉孕酚苷)及其苷元--γ-地吉孕宁分别转化为异地吉孕宁及其苷元--α-地吉孕宁。用酸回流时,α-二脂原素失去了水元素,形成了 β-二脂原素。通过与孕-4-烯-3,11,15,20-四酮与碱或酸异构化的产物进行比较,从 β-二脂原素中用乙酸和锌粉还原,再用奥普瑙尔氧化法得到的⊿4-3-氧代化合物的结构被确定为 14β,17α-孕-4-烯-3,11,15,20-四酮。因此,β-二脂原蛋白的结构被推测为 3β-hydroxy-14β-pregna-5, 16-diene-11, 15, 20-triione,而 α 和 γ-二脂原蛋白中的叔羟基将位于 17 位。鉴于α-二降头素对稀碱或稀酸的稳定性,以及与γ-二降头素相比它对光学旋转的负作用,将 3β,17α-二羟基-14β-孕甾-5-烯-11,15,20-三酮和 3β,17α-二羟基孕甾-5-烯-11,15,20-三酮的结构分别赋予α-和γ-二降头素是合适的。地吉孕宁是γ-地吉孕宁的单二萜苷。