Synthetic Studies on Vitamin D Analogues VI. A New Synthesis of 25-Hydroxycholesterol from Lithocholic Acid

Miyamoto, K.; Kubodera, Noboru; Murayama, Eigoro; Ochi, Kiyoshige; Mori, Takashi; Matsunaga, Isao

doi:10.1080/00397918608078765

Cited by 24 publications

(8 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Compound 5 was obtained by reduction of the a,b-unsaturated ester described above with diisobutylaluminum hydride, followed by aqueous acid treatment. Compound 10 44,45) was obtained by esterification of cholenic acid 16 (purchased from Steraloids Inc. Wilton, NH, U.S.A., Chart 2) with trimethylsilyldiazomethane. 46) Compound 4 47) was prepared by LiAlH 4 reduction of compound 10.…”

Section: Methodsmentioning

confidence: 99%

Coordination of Sodium Cation to an Oxygen Function and Olefinic Double Bond to Form Molecular Adduct Ion in Fast Atom Bombardment Mass Spectrometry.

Morisaki

Kobayashi

Yamamura

et al. 2002

CHEMICAL & PHARMACEUTICAL BULLETIN

View full text Add to dashboard Cite

One of the most important uses of mass spectrometry in organic chemistry is in the determination of molecular weight (MW: M). In fast atom bombardment (FAB) mass spectrometry, 1-3) molecular-related ion peaks of organic compounds are generally observed as [MϩH] ϩ , [M] ϩ , [MϪH] ϩ or [Mϩ2H] ϩ (for positive ion), depending on the structures. However, compounds which decompose during the analyses show only very weak or no molecular-related ion peaks. In such cases, addition of an alkali metal salt to the compounds sometimes helps to induce adduct ion peaks [MϩA] ϩ (A: atomic weight of alkali metal), and these peaks have also been used for molecular weight determination in FAB mass spectrometry. 4-7)Alkali metal adduct ions of organic compounds are observed in FAB mass analyses of various compounds, especially polyoxygenated compounds such as saccharides [8][9][10][11] and polyethers, [12][13][14][15] and polyfunctional compounds such as peptides. [16][17][18][19] We previously reported the structural requirements of oxygen functional groups for stabilization of the adduct ions in FAB mass spectra of a variety of diols and related compounds with the addition of NaCl. 7) Compounds with two proximal oxygens efficiently coordinated to Na ϩ , and afforded the adduct ion peaks [MϩNa] ϩ [Chart 1a]. However, compounds with an isolated hydroxyl group or ether oxygen hardly formed a complex with Na ϩ , and the intensities of the Na ϩ adduct ion peaks were negligible compared to those of diols, including n-hexadecane-1,2-diol (12), which formed stable Na ϩ adduct ions.7)The affinity of alkali metal cations to p-electrons has been extensively investigated on the basis of cation p-interactions. [20][21][22][23][24][25][26][27][28] Experiments to determine the binding energies of alkali metal cations with benzene and ethylene in the gas phase have been carried out by mass analyses of ion-molecule binding under solvent-free conditions and without counter ion influence. [22][23][24] Theoretical studies have also been carried out to calculate the binding energies of alkali metal cations to aromatic compounds.25-27) As described above, our previous studies showed that compounds with an isolated hydroxyl group hardly formed a complex with Na ϩ under FAB mass spectrometric conditions. 7) However, if an olefinic double bond and Na ϩ could interact, allylic alcohols might form a complex with Na ϩ by the participation of both the hydroxyl group and the olefinic double bond to yield [MϩNa] ϩ ion peaks effectively [Chart 1b]. Allylic alcohols are susceptible to dehydroxylation (protonation followed by dehydration to form the allylic cation) under FAB mass spectrometric conditions, but if the hydroxyl group and olefinic double bond were coordinated to Na ϩ , the complex might not readily undergo dehydroxylation, as in the case of 1,2-diols. 7)This paper reports the interactions of Na ϩ with allylic alcohols in FAB mass spectrometry. Steroidal allylic alcohols, in which a,b-unsaturated hydroxyl groups were located in ring A ...

show abstract

Section: Methodsmentioning

confidence: 99%

Coordination of Sodium Cation to an Oxygen Function and Olefinic Double Bond to Form Molecular Adduct Ion in Fast Atom Bombardment Mass Spectrometry.

Morisaki

Kobayashi

Yamamura

et al. 2002

CHEMICAL & PHARMACEUTICAL BULLETIN

View full text Add to dashboard Cite

show abstract

“…Although the formation of ( E )/( Z )-diastereomers was expected, the 1 H and 13 C NMR spectra reveal only one set of signals, indicating a single diastereomer, presumably ( E) - 16 . LiBr and Li 2 CO 3 were used to induce dehydrobromination (β-elimination), resulting in the formation of completely conjugated compound 15 , which was isolated in a 88% yield [ 40 ]. The 1 H NMR spectrum of 15 reveals two distinct sets of signals, indicating the presence of ( E )- and ( Z )-configured esters 15 in the ratio 9:1.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Antioxidative Properties of 1,2,3,4-Tetrahydropyridine Derivatives with Different Substituents in 4-Position

et al. 2022

View full text Add to dashboard Cite

Natural products are an excellent source of inspiration for the development of new drugs. Among them, betalains have been extensively studied for their antioxidant properties and potential application as natural food dyes. Herein, we describe the seven-step synthesis of new betalamic acid analogs without carboxy groups in the 2- and 6-position with an overall yield of ~70%. The Folin–Ciocalteu assay was used to determine the antioxidant properties of protected intermediate 21. Additionally, the five-step synthesis of betalamic acid analog 35 with three ester moieties was performed. Using NMR techniques, the stability of the obtained compounds towards oxygen was analyzed.

show abstract

“…The nucleophiric reaction of (17) with alkoxides, derived from glycols and potassium tert-butoxide (t-BuOK), resulted in regio-and stereoselective introduction of the hydroxyl-ether group at the 2b-position of (25), which was then irradiated and thermally isomerized to (26). The method was then extended to 1,2a-epoxide (29) with a hydroxyl group at C-25, prepared from lithocholic acid (27) via 25-hydroxycholesterol (28) by 24-step [30]. Eldecalcitol (3), which possesses a hydroxypropoxy group at the 2b-position, was finally selected as an analog with potent calcemic actions [5] (Fig.…”

Section: Exploratory Research For Eldecalcitolmentioning

confidence: 99%

Analogs for the Treatment of Osteoporosis ∗

Kubodera¹,

Takahashi²

2011

Vitamin D

Self Cite

View full text Add to dashboard Cite

Synthetic Studies on Vitamin D Analogues VI. A New Synthesis of 25-Hydroxycholesterol from Lithocholic Acid

Cited by 24 publications

References 9 publications

Coordination of Sodium Cation to an Oxygen Function and Olefinic Double Bond to Form Molecular Adduct Ion in Fast Atom Bombardment Mass Spectrometry.

Coordination of Sodium Cation to an Oxygen Function and Olefinic Double Bond to Form Molecular Adduct Ion in Fast Atom Bombardment Mass Spectrometry.

Synthesis and Antioxidative Properties of 1,2,3,4-Tetrahydropyridine Derivatives with Different Substituents in 4-Position

Analogs for the Treatment of Osteoporosis ∗

Contact Info

Product

Resources

About