TiCl 催化（25R）-22-氧代-23-螺缩酮裂解。在侧链上具有呋甾烷醇和吡喃酮 E 环的甾体皂甙元的合成。
TiCl catalyzed cleavage of (25R)-22-oxo-23-spiroketals. Synthesis of sapogenins with furostanol and pyranone E rings on the side chain.
机构信息
Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Ed.B-1, C.U., Morelia, Michoacán 58030, Mexico.
Departamento de Química, CINVESTAV-IPN, Apdo. Postal 14-740, México, D.F., 07000, Mexico.
出版信息
Steroids. 2019 Dec;152:108488. doi: 10.1016/j.steroids.2019.108488. Epub 2019 Sep 6.
The regioselective opening of the F ring of 22-oxo-23-spiroketals 7a-d using TiCl in acetic anhydride yielded the novel furostanols 11a-d along with cholestanic derivatives 8a-d with pyranone E ring. The structures of the new derivatives thus obtained were established using one- (DEPT) and two-dimensional H, C NMR experiments (COSY, HSQC, HMBC, NOESY). The 22α-hydroxyl orientation in compounds 11a-d was proposed by comparison of the C chemical shifts with those of other aglycone members of this family, and confirmed by combined NOESY and X-ray diffraction analysis of compound 11a.
用 TiCl 在醋酸酐中打开 22-氧代-23-螺缩酮 7a-d 的 F 环，得到了新型呋甾醇 11a-d 以及带有吡喃酮 E 环的胆甾烷衍生物 8a-d。使用一维（DEPT）和二维 H、C NMR 实验（COSY、HSQC、HMBC、NOESY）确定了新衍生物的结构。通过与该家族其他糖苷配基的 C 化学位移比较，提出了化合物 11a-d 中 22α-羟基的取向，并通过化合物 11a 的综合 NOESY 和 X 射线衍射分析得到了证实。
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