2857-42-3Relevant articles and documents
Synthesis of estrone via a thallium(III)-mediated fragmentation of a 19-hydroxy-androst-5-ene precursor
Kocovsky,Baines
, p. 6139 - 6140 (1993)
Estrone (6) has been synthesized from 1, an industrial precursor of androstane steroids, in seven steps. Key features of the strategy include the functionalization of C-19 (1 → 2) and a stereoelectronically controlled, Tl(III)-mediated degradation (2 → 3). Oppenauer oxidation of diol 4 then gave the unsaturated hydroxyketone 5, acid treatment of which induced aromatization affording 6.
Facile Access to Bridged Ring Systems via Point-to-Planar Chirality Transfer: Unified Synthesis of Ten Cyclocitrinols
Wang, Yu,Ju, Wei,Tian, Hailong,Sun, Suyun,Li, Xinghui,Tian, Weisheng,Gui, Jinghan
supporting information, p. 5021 - 5033 (2019/03/26)
Bridged ring systems are found in a wide variety of biologically active molecules including pharmaceuticals and natural products. However, the development of practical methods to access such systems with precise control of the planar chirality presents considerable challenges to synthetic chemists. In the context of our work on the synthesis of cyclocitrinols, a family of steroidal natural products, we herein report the development of a point-to-planar chirality transfer strategy for preparing bridged ring systems from readily accessible fused ring systems. Inspired by the proposed pathway for biosynthesis of cyclocitrinols from ergosterol, our strategy involves a bioinspired cascade rearrangement, which enabled the gram-scale synthesis of a common intermediate in nine steps and subsequent unified synthesis of 10 cyclocitrinols in an additional one to three steps. Our work provides experimental support for the proposed biosynthetic pathway and for the possible interrelationships between members of the cyclocitrinol family. In addition to being a convenient route to 5(10→19)abeo-steroids, our strategy also offers a generalized approach to bridged ring systems via point-to-planar chirality transfer. Mechanistic investigations suggest that the key cascade rearrangement involves a regioselective ring scission of a cyclopropylcarbinyl cation rather than a direct Wagner-Meerwein rearrangement.
COMPOUNDS AND METHODS FOR TREATING NEOPLASIA
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Page/Page column 94, (2012/02/13)
The invention features compounds, pharmaceutical compositions and methods useful for the treatment of neoplasia. In particular embodiments, the compounds of the invention are useful for the treatment of multidrug resistant neoplasia.
