Reactions of steroidal 4,5- and 5,6-epoxides with strong bases

Holland, Herbert L.

doi:10.1139/v83-377

Cited by 20 publications

(14 citation statements)

References 19 publications

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“…Further 'The authors are grateful to a referee for drawing attention to this paper. Can 24-Methylenecholesta-3,5-dien-7-one, 13 Hydrolysis of 7 (25 mg) employing 5% ethanolic KOH (5 mL) at reflux for 2 h afforded, after work-up and ptlc purification, compound …”

Section: Extractions and Separationsmentioning

confidence: 99%

Novel sterols from the finger sponge Haliclonaoculata

Findlay¹,

Patil²

1985

Can. J. Chem.

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From the finger sponge, Haliclona oculata (Linnaeus), six new polar sterols have been isolated and their structures determined by chemical and spectroscopic means. These are 3P-hydroxy-cholesta-5,25-dien-24-one (2), 3P-hydroxy-24-methylene-5-cholesten-7-one (6), 24-methylene-5-cholesten-3P,7P-diol (9), 24-methylcholesta-5,22-dien-3P,7P-diol ( l l ) , 24-methylene-5-cholesten-3P,7a-diol (12), and 5~,6-epoxy-24-methylene-cholestan-3~-ol(16). Also shown to be present are the known monohydroxysterols (22E,24S)-24-methylcholesta-5,22-dien-3P-ol (I), (22Z)-24-norcholesta-5,22-dien-3P-ol, 24-methylene-5-cholesten-3p-01, 24-isoethylidene-5-cholesten-3P-01, (22E)-24-norcholesta-5,22-dien-3P-ol and (23E)-cholesta-5.23-dien-3P,25-diol. The structure 14 is tentatively proposed for a novel CZ4 sterol and 8 is suggested for the structure of a compound accompanying 6. JOHN A. FINDLAY et ASHOK D. PATIL. Can. J. Chem. 63, 2406Chem. 63, (1985.On a is016 six nouveaux sttrols polaires de 1'Cponge Haliclona oculata (Linnaeus) et on a determink leurs structures par des mCthodes chimiques et spectroscopiques. I1 s'agit de I'hydroxy-3P cholestadikne-5,25 one-24 (2), de l'hydroxy-3P mCthyl2ne-24 cholesti?ne-5 one-7 (6), du mCthylkne-24 cholestkne-5 diol-3P,7P (9), du mCthyl-24 cholestadi6ne-5,22 diol-3P,7P (11), du mCthylkne-24 cholestkne-5 diol-3P,7a (12) Chemical studies on sponges have shown that they often are a source of novel sterols of biogenetic interest (1, 2). As part of a continuing study of marine natural products from Bay of Fundy organisms, we have examined the sterols of the abundant finger sponge Haliclona oculata (Linnaeus) and now report our findings.Thin-layer chromatography (tlc) of fractions from silica gel column chromatography of a methanol extract of H. oculata showed the presence of substantial amounts of compounds more polar than the monohydroxylated sterol fraction. The five major monohydroxylated sterols were separated and identified by comparison of their spectral characteristics with literature data. The major sterol (85%) of this fraction proved to be (22E,24S)-24-methylcholesta-5,22-dien-3P-ol (22-dehydrocampesterol), 1 (3, 4), while other components were identified as (22Z)-24-norcholesta-5,22-dien-3P-ol(4) (1.5%), 24-methylene-5-cholesten-3P-01 (5) (2.4%), 24-isoethylidene-5-cholesten-3P-01 (isofucosterol) (4) (2.9%), and (22E)-24-norcholesta-5,22-dien-3P-01 (4) (0.8%).Purification of the more polar sterols was achieved by a combination of column chromatography, preparative tlc, and high pressure liquid chromatography (hplc) on silica gel and reverse phase systems. In some cases it was necessary to separate mixtures after acetylation. In this manner we have succeeded in isolating and characterizing the six new sterols 2, 6, 9, 11, 12, and 16, plus the previously reported diene diol4 (6).The novel ketone 2 was purified as its acetate 3 whose ir spectrum (CHCl,) displays strong bands at 1730 and 1670 cm-' attributed to the ester and a,P-unsaturated ketone, respec- For personal use only.

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Section: Extractions and Separationsmentioning

confidence: 99%

Novel sterols from the finger sponge Haliclonaoculata

Findlay¹,

Patil²

1985

Can. J. Chem.

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“…F;~y ' y.q " <(I C reassigned following a consideration of the spectra of the compounds (1 8) and a consideration of the effect of the introduction of unsaturation in the 6,7 position (19). Following the successful use of A'.5 en01 acetates as…”

Section: \ /mentioning

confidence: 99%

Microbial hydroxylation of steroids. 9. Epoxidation of Δ⁶-3-ketosteroids by Rhizopusarrhizus ATCC 11145, and the mechanism of the 6β hydroxylase enzyme

Holland¹,

Chenchaiah²,

Thomas³

et al. 1984

Can. J. Chem.

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A series of A"3-ketosteroids has been incubated with the C-6P hydroxylating fungus Rhizopus arrhizus ATCC 1 1145. Ring A aromatic steroids are not metabolized by this fungus, nor are 3-chloro-and 3-(N-pyrrolideno)-androsta-3,Sdienes.A'.'-3-~etosteroids are epoxidized at the 6.7 position by R. arrhizus with P stereochemistry; in contrast, both 5a-and 5P-A"3-ketosteroids are epoxidized with a stereochemistry by fungal and peracid reagents. The results of this and previous studies now make it possible to define the nature of the hydroxylating/epoxidizing species of the 6P hydroxylase enzyme of R. arrhizrts. Evidence is presented for a stepwise reaction mechanism in both cases. Improved methods of synthesis are described for 6-methylene-testosterone and estra-4,6-dien-l7P-ol-3-one.HERBERT L. HOLLAND, P. CHINNA CHENCHAIAH, EVERTON M. THOMAS, BEATRIX MADER et MICHAEL J. DENNIS. Can. J. Chem. 62, 2740Chem. 62, (1984.On a procede i l'incubation d'une serie de Ah ceto-3 steroi'des en presence du champignon Rhizopus arrhizus ATCC 1 1 145 qui provoque des rtactions d'hydroxylation en C-6P. Les steroi'des comportant un cycle A aromatique ainsi que les chloro-3 ou (N-pyrro1ideno)-3 androstadiknes-3,5 ne sont pas mCtabolisCs par ce champignon. Sous I'influence du R. arrhizus, les A4.6 ctto-3 steroi'des subissent une reaction d'epoxydation en position 6,7 et la sterkochimie de la reaction est P; par opposition, les Ah ctto-3 steroi'des tant de la serie 5 a que de la serie 5P subissent des rkactions d'epoxydation dont la stdrtochimie est a tant sous I'action des champignons que des peracides. Grice aux resultats de la presente etude ainsi que ces obtenus anttrieurement, il est maintenant possible de definir la nature des espkces, presentes dans I'enzyme hydroxylase 6P du R. arrhizus, qui provoquent les reactions d'hydroxylation et d'epoxydation. Dans chacun de ces cas, on presente des donnkes qui suggkrent un micanisme rkactionnel par Ctapes. On decrit des methodes ameliorees de synthkse pour la mCthylkne-6 testosterone ainsi que pour I'estradiene-4,6 01-17P one-3.[Traduit par le journal]

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“…Previous literature data reported the partial characterization of these compounds, [7,10,11] but from these data we were unable to distinguish between the two epoxides due to incoherent NMR results. [10,11] With the techniques now available (NMR spectroscopy and X-ray crystallography) we concluded that several previous NMR assignments are not correct.…”

Section: Oxidation Of 4-cholestene (2)mentioning

confidence: 69%

Oxidation of Δ⁴‐ and Δ⁵‐Steroids with Hydrogen Peroxide Catalyzed by Porphyrin Complexes of Mn^III and Fe^III

et al. 2004

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Reactions of steroidal 4,5- and 5,6-epoxides with strong bases

Cited by 20 publications

References 19 publications

Novel sterols from the finger sponge Haliclonaoculata

Novel sterols from the finger sponge Haliclonaoculata

Microbial hydroxylation of steroids. 9. Epoxidation of Δ⁶-3-ketosteroids by Rhizopusarrhizus ATCC 11145, and the mechanism of the 6β hydroxylase enzyme

Oxidation of Δ⁴‐ and Δ⁵‐Steroids with Hydrogen Peroxide Catalyzed by Porphyrin Complexes of Mn^III and Fe^III

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Reactions of steroidal 4,5- and 5,6-epoxides with strong bases

Cited by 20 publications

References 19 publications

Novel sterols from the finger sponge Haliclonaoculata

Novel sterols from the finger sponge Haliclonaoculata

Microbial hydroxylation of steroids. 9. Epoxidation of Δ6-3-ketosteroids by Rhizopusarrhizus ATCC 11145, and the mechanism of the 6β hydroxylase enzyme

Oxidation of Δ4‐ and Δ5‐Steroids with Hydrogen Peroxide Catalyzed by Porphyrin Complexes of MnIII and FeIII

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Microbial hydroxylation of steroids. 9. Epoxidation of Δ⁶-3-ketosteroids by Rhizopusarrhizus ATCC 11145, and the mechanism of the 6β hydroxylase enzyme

Oxidation of Δ⁴‐ and Δ⁵‐Steroids with Hydrogen Peroxide Catalyzed by Porphyrin Complexes of Mn^III and Fe^III