Steroidal alkaloids synthetic studies

Synthetic studies on the Salamander alkaloids have been reviewed.67 The synthesis of 18-amino-steroids that are related to the alkaloid batrachotoxin has been discussed.68... 

Marine natural products have been extensively reviewed in many monographs and journals (1-17). Kobayashi and Ishibashi have reviewed marine alkaloids in general in this series (16), and our recent review (17) provides an account of toxic alkaloids of marine origin. This chapter is intended to provide the reader a brief description of the isolation, structure elucidation, synthetic studies, and biological screening of important classes of steroidal alkaloids and amines of marine origin. 

The use of anisoles (22) as synthetic equivalents to cyclohex-2-enones (Scheme 3) has been widespread since the original observations of Birch, and the literature is replete with examples over the past five decades, e.g. in the syntheses of steroids, terpenoids and alkaloids. The most thorough studies have been carried out within the context of the conversion of estrone derivatives to 19-norandrostane and pregnane derivatives and are instructive for the selection of reagents and reaction parameters for reductions of this general type. ... 

On closer comparison of these successful routes, several distinct styles are apparent. The early approaches of Gates and Ginsburg are truly "synthetic", effectively working blindfolded due to their reliance upon knowledge gained solely from the extensive, but essentially crude, degradative structural studies in fact, as a result, morphine synthesis has probably offered as much to phenanthrene, and in turn to steroid chemistry, as to actual production of the alkaloid itself ... 

Examples of this technique are described for artificial receptors for the alkaloid yohimbine binding peptides obtained from a phage display library [57], for the steroid libraries related to lla-hydroxyprogesterone [58], corticosterone [58] (reported in Fig. 12), and cortisol [59]. A molecularly imprinted polymer working as a synthetic receptor for a series of chiral benzodiazepines [47], artificial receptors for the tricyclic antidepressant drug nortriptyline—obtained by covalent and noncovalent molecular imprinting and studied by capillary liquid chromatography with a simulated combinatorial library [60,61]—were also examined. 

Non-nucleotide pol inhibitors have been discovered among different classes of namral and synthetic chemical compounds. The main of them are long-chain fatty acids, fatty acid derivatives, bile acid derivatives, steroid derivatives, triterpenoids, cerebrosides, alkaloids, flavonoids, anthocyanins, glycolipids, catechins, coenzyme Qs, isosteviols, dipeptide alcohols, vitamins, etc. [52, 53]. The most well-studied non-nucleotide inhibitors are presented in Table 4.2. 

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