Stereoselective synthesis and solvolytic behavior of the isomeric 7-dehydrocholesterol 5,6-oxides

Michaud, Dennis P.; Nashed, Nashaat T.; Jerina, Donald M.

doi:10.1021/jo00211a009

Cited by 37 publications

(22 citation statements)

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“…Chemical stability of this epoxide and its 5β,6β-isomer has also been reported (46). Our present demonstration of 1,2-hydrogen migration from C-6 to C-5 position strongly suggests that the 5α,6α-epoxide would produce 5β-ketol via epoxy-carbonyl rearrangement as shown in path "a" of Scheme 8.…”

Section: -Hydroxyecdysone Biosynthesissupporting

confidence: 78%

Biosynthesis of sterols and ecdysteroids in Ajuga hairy roots

Fujimoto¹,

Ohyama²,

Nomura³

et al. 2000

Lipids

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Hairy roots of Ajuga reptans var. atropurpurea produce clerosterol, 22-dehydroclerosterol, and cholesterol as sterol constituents, and 20-hydroxyecdysone, cyasterone, isocyasterone, and 29-norcyasterone as ecdysteroid constituents. To better understand the biosynthesis of these steroidal compounds, we carried out feeding studies of variously 2H- and 13C-labeled sterol substrates with Ajuga hairy roots. In this article, we review our studies in this field. Feeding of labeled desmosterols, 24-methylenecholesterol, and 13C2-acetate established the mechanism of the biosynthesis of the two C29-sterols and a newly accumulated codisterol, including the metabolic correlation of C-26 and C-27 methyl groups. In Ajuga hairy roots, 3alpha-, 4alpha-, and 4beta-hydrogens of cholesterol were all retained at their original positions after conversion into 20-hydroxyecdysone, in contrast to the observations in a fern and an insect. Furthermore, the origin of 5beta-H of 20-hydroxyecdysone was found to be C-6 hydrogen of cholesterol exclusively, which is inconsistent with the results in the fern and the insect. These data strongly support the intermediacy of 7-dehydrocholesterol 5alpha,6alpha-epoxide. Moreover, 7-dehydrocholesterol, 3beta-hydroxy-5beta-cholest-7-en-6-one (5beta-ketol), and 3beta,14alpha-dihydroxy-5beta-cholest-7-en-6-one (5beta-ketodiol) were converted into 20-hydroxyecdysone. Thus, the pathway cholesterol-->7-dehydrocholesterol-->7-dehydrocholesterol 5alpha,6alpha-epoxide-->5beta-ketol-->5beta-k etodiol is proposed for the early stages of 20-hydroxyecdysone biosynthesis. 3beta-Hydroxy-5beta-cholestan-6-one was also incorporated into 20-hydroxyecdysone, suggesting that the introduction of a 7-ene function is not necessarily next to cholesterol. C-25 Hydroxylation during 20-hydroxyecdysone biosynthesis was found to proceed with ca. 70% retention and 30% inversion. Finally, clerosterol was shown to be a precursor of cyasterone and isocyasterone.

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Section: -Hydroxyecdysone Biosynthesissupporting

confidence: 78%

Biosynthesis of sterols and ecdysteroids in Ajuga hairy roots

Fujimoto¹,

Ohyama²,

Nomura³

et al. 2000

Lipids

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“…To test this proposal for DHCEO formation, 7-DHC 5 ␣ ,6 ␣ -epoxide ( 1 ) was prepared by epoxidation of 7-DHC with peroxyimidic acid generated in situ from acetonitrile and hydrogen peroxide under basic condition (see supplementary data) ( 59 ). The 3 ␤ ,5 ␣ ,6 ␤ -triol ( 2 ) was prepared by hydrolysis of 1 in acidic buffer (see supplementary data) ( 60 ).…”

Section: Dhceo Can Be Formed From 5 ␣ 6 ␣ -Epoxycholest-7-en-3 ␤ -Olmentioning

confidence: 99%

An oxysterol biomarker for 7-dehydrocholesterol oxidation in cell/mouse models for Smith-Lemli-Opitz syndrome

Korade

Rosado

et al. 2011

Journal of Lipid Research

186

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“…These data proposed that 3 was a polyhydroxylated 24-methylcholest-type sterol, similar to 4, 10 5, 11 ergosta-7,22E-diene-3ˇ,5˛,6˛-triols, 17 and other analogs. 18 Comparison of the 1 H and 13 C NMR spectral data of 3 with those of 5 11 revealed that the only obvious difference between them was that one methine was oxygenated to be quaternary carbon, correspondingly the amount of methyl singlets was four instead of two in 3. This suggested that C-25 (υ C 73.4, s) was oxygenated, which was proved by the HMBC spectrum showing correlations of υ H 1.12 (3H, s, Me-26), 1.08 (3H, s, Me-27) with υ C 44.4 (d, C-24), 73.4 (s, C-25), and υ H 1.01 (3H, d, J D 6.9 Hz, Me-28) with υ C 73.4 (s, C-25) (Fig.…”

Section: Resultsmentioning

confidence: 99%

Complete ¹H and ¹³C NMR assignments of three new polyhydroxylated sterols from the South China Sea gorgonian Subergorgia suberosa

Zhang

Wang

et al. 2007

Magnetic Reson in Chemistry

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Three new polyhydroxylated sterols, 3beta,6alpha,11,20beta,24-pentahydroxy- 9,11-seco-5alpha-24-ethylcholest-7,28-diene-9-one (1), 3-(1',2'-ethandiol)-24- methylcholest-8(9),22E-diene-3beta,5alpha,6alpha,7alpha,11alpha-pentaol (2), 24-methylcholest-7,22 E-diene-3beta,5alpha,6beta,25-tetraol (3) together with five known sterols, were isolated from the EtOH/CH2Cl2 extract of the South China Sea gorgonian Subergorgia suberosa. The complete assignments of the 1H and 13C NMR chemical shifts for these new compounds were achieved by means of 1D and 2D NMR techniques, including HSQC, HMBC, 1H--1H COSY, and NOESY spectra.

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Stereoselective synthesis and solvolytic behavior of the isomeric 7-dehydrocholesterol 5,6-oxides

Cited by 37 publications

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Biosynthesis of sterols and ecdysteroids in Ajuga hairy roots

Biosynthesis of sterols and ecdysteroids in Ajuga hairy roots

An oxysterol biomarker for 7-dehydrocholesterol oxidation in cell/mouse models for Smith-Lemli-Opitz syndrome

Complete ¹H and ¹³C NMR assignments of three new polyhydroxylated sterols from the South China Sea gorgonian Subergorgia suberosa

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Stereoselective synthesis and solvolytic behavior of the isomeric 7-dehydrocholesterol 5,6-oxides

Cited by 37 publications

References 0 publications

Biosynthesis of sterols and ecdysteroids in Ajuga hairy roots

Biosynthesis of sterols and ecdysteroids in Ajuga hairy roots

An oxysterol biomarker for 7-dehydrocholesterol oxidation in cell/mouse models for Smith-Lemli-Opitz syndrome

Complete 1H and 13C NMR assignments of three new polyhydroxylated sterols from the South China Sea gorgonian Subergorgia suberosa

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Complete ¹H and ¹³C NMR assignments of three new polyhydroxylated sterols from the South China Sea gorgonian Subergorgia suberosa