The Stereochemistry of Oxidation of Some B-Norsteroids

Hanson, James R.; Manickavasagar, Revathy; Thangavelu, Vasuki

doi:10.1039/a805248d

Cited by 5 publications

(7 citation statements)

References 6 publications

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“…Interestingly, the first triterpenoid with a spiranoid-γ-lactone side chain was jaborosalactone P (230), which was collected over 30 years ago in extracts of Jaborosa odonelliana collected in Argentina [216]. Other related metabolites, such as jaborosalactone 12 (231), jaborosalactone 15 (232), and jaborosalactone 31 (233), were isolated from Jaborosa odonelliana, and jaborosalactone P was the major component in all samples collected in both spring and summer. In addition, jaborosalactone 31 (230) was found in extracts of all species studied, J. rotacea, J. odonelliana, J. runcinata, and J. araucana [217][218][219].…”

Section: Miscellaneous Cyclosteroids and Triterpenoids Derived From Marine And Terrestrial Sourcesmentioning

confidence: 99%

Antitumor Profile of Carbon-Bridged Steroids (CBS) and Triterpenoids

2021

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This review focuses on the rare group of carbon-bridged steroids (CBS) and triterpenoids found in various natural sources such as green, yellow-green, and red algae, marine sponges, soft corals, ascidians, starfish, and other marine invertebrates. In addition, this group of rare lipids is found in amoebas, fungi, fungal endophytes, and plants. For convenience, the presented CBS and triterpenoids are divided into four groups, which include: (a) CBS and triterpenoids containing a cyclopropane group; (b) CBS and triterpenoids with cyclopropane ring in the side chain; (c) CBS and triterpenoids containing a cyclobutane group; (d) CBS and triterpenoids containing cyclopentane, cyclohexane or cycloheptane moieties. For the comparative characterization of the antitumor profile, we have added several semi- and synthetic CBS and triterpenoids, with various additional rings, to identify possible promising sources for pharmacologists and the pharmaceutical industry. About 300 CBS and triterpenoids are presented in this review, which demonstrate a wide range of biological activities, but the most pronounced antitumor profile. The review summarizes biological activities both determined experimentally and estimated using the well-known PASS software. According to the data obtained, two-thirds of CBS and triterpenoids show moderate activity levels with a confidence level of 70 to 90%; however, one third of these lipids demonstrate strong antitumor activity with a confidence level exceeding 90%. Several CBS and triterpenoids, from different lipid groups, demonstrate selective action on different types of tumor cells such as renal cancer, sarcoma, pancreatic cancer, prostate cancer, lymphocytic leukemia, myeloid leukemia, liver cancer, and genitourinary cancer with varying degrees of confidence. In addition, the review presents graphical images of the antitumor profile of both individual CBS and triterpenoids groups and individual compounds.

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Section: Miscellaneous Cyclosteroids and Triterpenoids Derived From Marine And Terrestrial Sourcesmentioning

confidence: 99%

Antitumor Profile of Carbon-Bridged Steroids (CBS) and Triterpenoids

2021

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“…27 3β-Hydroxy-B-norandrost-5-en-17-one gave the corresponding B-norandrost-4-ene-3,6,17trione. 28 Reduction of the unsaturated ketone with zinc and acetic acid gave 5β-B-norcholestane-3,6-dione. In the normal cholestane series this reduction gives the trans 5α-isomer.…”

Section: James Hanson Cavit Uyanikmentioning

confidence: 99%

The Chemistry of B-Norsteroidal 6-Ketones and their Relatives

Uyanık

Hanson

2011

Journal of Chemical Research

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His research interests include thechemistry and biosynthesis of natural products particularly terpenoids, steroids and fungal metabolites. Over the past 50 years he has published over 500 papers and reviews and 12 books. Introduction 2 Synthesis 3 Stability of the ring junctions 4 Bromination of the 6-ketones 5 Reduction of the ketones 6 Grignard reactions of 6-ketones 7 Beckmann rearrangement of 6-oximino-Bnorsteroids 8 Conclusion 9 References

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“…In the normal steroid series, it provided a useful means of introducing a 4b-acetoxyl substituent. 14,15 However, treatment of 3b-hydroxy-B-norandrost-5-en-17-one gave the fragmentation product 13 and a mixture of the expected 4b-acetoxy-3b-hydroxyandrost-5-en-17-one and a smaller amount of the isomeric 3b-acetoxy-4b-hydroxy-Bnorandrost-5-en-17-one. When 3b-acetoxy-B-norandrost-5ene was used as a substrate, apart from acetoxylation products and 6-bromo-5-alkene compound, backbone rearrangement products were obtained.…”

Section: Hydrogenationmentioning

confidence: 99%

“…In the case of the B-norsteroids, a greater proportion of the product is the 5a,6a-epoxide. 18,19 Epoxidation with magnesium bis(monoperoxyphthalate) hexahydrate has been reported 20 to be a highly efficient method for producing the 5a,6a-epoxides in the B-norsteroid series. Whereas epoxidation with KMnO 4 :FeSO 4 gives the 5b,6b-epoxide in the normal 6:6 series, in the B-norsteroids the product is the 5a,6a-epoxide.…”

Section: Epoxidationmentioning

confidence: 99%

“…32 Whilst under some conditions cyclosteroid products comparable to those in the 6:6 series such as 6b-hydroxy-3a,5a-cyclo-B-norandrostan-17-one were isolated from these reactions, in the B-norsteroid series a greater proportion of the products arose from attack on ring A at C-3 rather than at C-6. 33 The diminished homoallylic participation of the C-5 : C-6 double bond is also revealed by the products of halogenation at C-3. 34 The major product of halogenation of both 3b-hydroxyandrost-5-en-17-one and the corresponding B-norsteroid with phosphorus pentachloride were the 3b-chlorides.…”

Section: The I-steroid Reactionmentioning

confidence: 99%

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