Beilstein J. Org. Chem.2019,15, 2003–2012, doi:10.3762/bjoc.15.196
lower than those of 4ß-hydroxywithanolide E. Our work establishes androwithanolides as a new subclass of withanolides.
Keywords: androstanes; Physalis peruviana; steroids; structure elucidation; withanolides; Introduction
Traditional medicine has long been a source of inspiration for modern drug
).
Irinans represent highly unusual withanolide derivatives, as they lack the side-chain lactone ring that is a common structural feature of virtually all known withanolides [3], but possess an androstane backbone instead. While androstanes such as androsterone (7) are well-known human sex hormones (Figure
characteristic of Physalis species.
The biosynthesis of androstanes in mammals requires three enzymatic steps starting from cholesterol (9, Figure 3B) [27]. Cholesterol (9) is converted to pregnenolone (10) by the cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc), which cleaves the C20–C22 bond
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Graphical Abstract
Figure 1:
Withanolides from Physalis peruviana. A) Structures of the newly characterised truncated withanolid...
Beilstein J. Org. Chem.2018,14, 2589–2596, doi:10.3762/bjoc.14.236
the reference compound, cisplatin.
Keywords: antiproliferative activity; Knorr reaction; microwave; pyrazol-5-ones; steroids; Introduction
17-exo-Heterocyclic androstanes with five or six-membered heterocyclic rings connected directly to C-17 of the sterane core represent a remarkable subclass of
the sterane framework; (iii) a hydroxy or keto group at C-3 and (iv) the presence of a C16–C17 double bond, which facilitates the inhibitory effect but is not an essential requirement. Some 17-heterocycle-substituted androstanes, even those that lack the structural features described above, are also
the sterane skeleton have been published, but not to C-17 [10]. Nevertheless, this heterocyclic scaffold is also an important building block in many clinically relevant drugs, agrochemicals, dyes, pigments and chelating agents [11][12][13], and therefore its introduction to C-17 of androstanes may be
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Graphical Abstract
Scheme 1:
Multistep synthesis of steroidal β-ketoesters 4 and 4' from pregnenolone acetate (1) and pregnadien...