Synthesis of biological precursors of cholic acid

This paper describes a new and convenient procedure for the synthesis of 5β-cholestane-3α,7α,12α,24-tetrol(24R and 24 S) and 5β-cholestane-3α, 7α, 12α, 26-tetrol starting from 5β-cholestane-3α,7α,12α,25-tetrol. Dehydration of the 25-hydroxytetrol with glacial acetic acid and acetic anhydride yielded a mixture of 5β-cholest-24-ene-3α,7α,12α-triol and the corresponding Δ²⁵ compound. Hydroboration and oxidation of the mixture of Δ²⁴ and Δ²⁵ unsaturated bile alcohols resulted in the formation of 5β-cholestane-3α,7α,12α,24ξ-tetrol and 5β-cholestane-3α,7α,12α,26-tetrol. In addition, smaller amounts of 5β-cholestane-3α, 7α, 12α, 23ξ-tetrol and 5β-cholestane-3α, 7α, 12α-triol were also obtained.The bile alcohols epimeric at C-24 were resolved by analytical and preparative TLC, characterized by gas-liquid chromatography and mass-spectrometry. Tentative assignments of the 24R and 24S configuration was made on the basis of molecular rotation differences. These compounds will be useful for biological studies of cholic acid biosynthesis.     

24xi-Methyl 5 alpha-cholestane-3 alpha,6 beta,9 alpha,25-tetrol 24-monoacetate, a novel polyhydroxylated steroid from the soft coral Sarcophyton tortuosum

A novel polyhydroxylated steroid, named sartortuosterol A, with rare 3 alpha- and 6-hydroxyl groups, was isolated from the South China Sea soft coral Sarcophyton tortuosum Tixier-Durivault, and its structure was established as 24xi-methyl 5 alpha-cholestane-3 alpha, 6 beta, 9 alpha,25-tetrol 25-monoacetate from spectroscopic data and chemical conversions.     

Synthesis and anti-glioma activity of 25(R)-spirostan-3β,5α,6β,19-tetrol

Malignant gliomas are common and aggressive brain tumours in adults. The rapid proliferation and diffuse brain migration are the main obstacles to successful treatment. Here, we show 25(R)-spirostan-3β,5α,6β,19-tetrol, a polyhydroxy steroid, is capable of suppressing proliferation and migration of C6 malignant glioma cells in a concentration-dependent manner. The compound 25(R)-spirostan-3β,5α,6β,19-tetrol was synthesised by seven steps starting from diosgenin in 8.55% overall yield. The structures of the synthetic compounds were characterised by infrared (IR), ¹H nuclear magnetic resonance (NMR), ¹³C NMR spectra and EA.     

Minor and trace sterols in marine invertebrates 39.1 24ξ,25ξ-24,26-cyclocholest-5-en-3β-ol,a novel cyclopropyl sterol.

The novel cyclopropyl sterol, 24ξ, 25ξ-24, 26-cyclocholest-5-en-3β-ol (24, 26-cyclocholesterol), has been isolated from the sponge $\text{Spheciospongia sp}$. ($\text{Spirastrella vagabunda}$ Ridley) and its structure established by spectral analysis and by correlation with papakusterol.     

Steroids in newborns and infants identification by combined gas chromatography-mass spectrometry of the major steroids excreted by a newborn chimpanzee (Pan troglodytes)

The following steroids have been identified by combined gas chromatography-mass spectrometry in a urine specimen collected from a newborn chimpanzee; 5-androstene-3β, 17α-diol, 3β,16α (and 16β)-dihydroxy-5-androsten-17-one, 5-androstene-3β, 16α, 17β-triol, 5-androstene-3β, 16β, 17α-triol, 5-pregnene-3β, 20α-diol, 5-pregnene-3β, 20α, 21-triol, 3β,21-dihydroxy-5-pregnen-20-one, 3β, 16α-dihydroxy-5-pregnen-20-one, 5-Piegnene-3β, 16α,20α, 21-tetrol, 5-pregnene-3β,17α, 20ξ, 21-tetrol androstenetriolones and androstenetetrols.     

Synthesis of 5beta-cholestane-3alpha, 7alpha, 12alpha, 25-tetrol and 5beta-cholestane-3alpha, 7alpha, 245, 25-pentol.

This paper describes syntheses of 5beta-cholestane-3alpha, 7alpha, 12alpha, 25-tetrol and 5beta-cholestane-3alpha, 7alpha, 12alpha, 24xi, 25-pentol which give higher yields than previously published methods. In addition, 5beta-cholestane-3alpha, 7alpha, 12alpha, 24xi, 25-pentol was synthesized by a different procedure, namely via performic acid oxidation of the correspinding unsaturated triol, which gave a lower yield but avoided the formation of 5beta-cholestane-3alpha, 7alpha, 12alpha, 25, 26-pentol, which normally tends to contaminate the final product. Structures were confirmed by gas-liquid chromatography, infrared-, proton magnetic resonance- and mass spectrometry, 5beta-Cholestane-3alpha, 7alpha, 12alpha, 25-tetrol and 5beta-cholestane-3alpha, 7alpha, 12alpha, 24xi, 25-pentol were required for in vivo and in vitro studies of the (hypothetical) 25-hydroxylation pathway of cholic acid biosynthesis.     

C26-analogs of naturally occurring bile alcohols-II. Preparation of 24-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,23-tetrols (23R and 23S) and 24-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,26-tetrols (25R and 25S) by a hydroboration procedure

A convenient procedure for the synthesis of 24-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,23-tetrol (23R and 23S) and 24-nor-5 beta-cholestane-3 alpha,7 alpha,12alpha,26-tetrol (25R and 25S) starting from 24-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,25-tetrol was developed. Dehydration of 24-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha, 25-tetrol with glacial acetic acid and acetic anhydride yielded a mixture of 24-nor-5 beta-cholest-23-ene-3 alpha,7 alpha,12 alpha-triol and the corresponding delta 25 compound. Hydroboration and oxidation of the mixture of unsaturated nor-triols resulted in the formation of 24-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,23-tetrols (23R and 23S) and 24-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,26-tetrols (25R and 25S). In addition, smaller amounts of 24-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,22 xi-tetrol and 24-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol were also obtained. The C26 bile alcohols epimeric at C-23 and C-25 were resolved by analytical and preparative TLC and characterized by gas-liquid chromatography and mass spectrometry. Provisional assignment of the configurations of the C-23 and C-25 hydroxyl groups were made on the basis of molecular rotation differences. These C26 alcohols will be used to test the stereospecificity of the hepatic enzymes that promote oxidation of the cholesterol side chain.     

24xi-Methylcholestane-3beta, 5alpha, 6beta, 12beta, 25-pentol 25-monoacetate, a novel polyoxygenated marine sterol.

24xi--Methylcholestane-3beta, 5alpha, 6beta, 12beta, 25-pentol 25-monoacetate has been isolated from an Alyconarian and its structure was established in part through extensive high resolution mass spectral and nmr studies and partly through the nonidentity of one of its degradation products with 24xi-methylcholestane-3beta, 5alpha, 6beta, 12alpha-tetrol synthesized from deoxycholic acid.     

Steroidal constituents of Solanum xanthocarpum

From the extract of the fruits of Solanum xanthocarpum (Solanaceae), five new steroidal compounds were isolated and characterized: 4α-methyl-24ξ-ethyl-5α-cholest-7-en-3β,22ξ-diol (1), 3β,22ξ-dihydroxy-4α-methyl-24ξ-ethyl-5α-cholest-7-en-6-one (2), 3β-benzoxy-14β,22ξ-dihydroxy-4α-methyl-24ξ-ethyl-5α-cholest-7-en-6-one (3), 3β-benzoxy-14α,22ξ-dihydroxy-4α-methyl-24ξ-ethyl-5α-cholest-7-en-6-one (4) and 3β-(p-hydroxy)-benzoxy-22ξ-hydroxy-4α-methyl-24ξ-ethyl-5α-cholest-7-en-6-one (5).     

Synthesis and structure of 26 (or 27)-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24S,25 xi-pentol isolated from the urine and feces of a patient with sitosterolemia and xanthomatosis

The urine and feces of a patient with the rare inherited lipid storage disease, sitosterolemia and xanthomatosis, were analyzed. Substantial quantities of C26-bile alcohol, 26 (or 27)-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24S,25 xi-pentol along with 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24-tetrol, 5 beta-cholestane-3 alpha,7 alpha,12 alpha,25-tetrol, 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24R,25-pentol, and 5 beta-cholestane-3 alpha,7 alpha,12 alpha,25,26-pentol were found. The structure of the C26-bile alcohol was confirmed by direct comparison (gas-liquid chromatography-mass spectrometry and thin-layer chromatography) with a standard sample synthesized from cholic acid. The configurational assignment at C-24 was determined by lanthanide-induced circular dichroism Cotton effect measurements. The increased excretion of these C26- and C27-bile alcohols suggests an abnormality of bile acid biosynthesis in this disease.     

Isolation of 20 alpha and 20 beta 5 beta-pregnane-3 alpha,17 alpha,20,21-tetrol (hexahydro-Reichstein's compound-S) in a case of congenital adrenal hyperplasia

5β-Pregnane-3α, 17α, 20α, 21-tetrol (l) and 5β-pregnane-3α, 17α 20β, 21-tetrol (II) have been isolated and identified from the urine of a girl with congenital adrenal hyperplasia. The total 5β-pregnane-3α, 17α, 20(α+β),21-tetrol consisted of 60% of I and 40% of II. The final identity of the compounds was established by gas chromatography — mass spectrometry. The mass spectra of the two trimethylsilyl isomers were closely related to each other in contrast to the spectra of five other pairs of C₂₁-C-20(α and β)-hydroxy steroid-trimethylsilyl-ethers. The mass spectra of free I and II also exhibited many common features, but were less similar to each other than their trimethylsilyl derivatives.     

Marine sterols. IX. Occurrence of 24 xi-methylcholestane-1 beta, 3 beta, 5 alpha, 6 beta, 25-pentol 25-monoacetate in the soft coral, Sarcophyton glaucum.

The southern Japan's soft coral, Sarcophyton glaucum, was found to contain several polyhydroxylates steroids. One of the minor components was isolated and its structure was established as 24 xi-methylcholestane-1 beta, 3 beta, 5 alpha, 6 beta, 25-pentol 25-monoacetate from spectral evidence and from comparison with a reference compound, 5 alpha-spirostan-1 beta, 3 beta, 5 alpha, 6 beta-tetrol, which was synthesized from ruscogenin. A mixture of 1 beta, 3 beta, 5 alpha, 6 beta-tetra hydroxy C27- and C28-sterols was also isolated.     

Marine natural products: 5alpha-cholestane-3beta,5,6beta,9-tetrol: a polyhydroxylated steroid from the gorgonian Pseudopterogorgia elisabethae.

A tetrahydroxylated steroid isolated from a gorgonian, $\text{Pseudopterogorgia elisabethae}$, has been shown by spectral analyses and degradative studies to be 5α-cholestane-3β,5,6β,9-tetrol.     

Metabolism of 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 26-tetrol and 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 25-tetrol into cholic acid in normal human subjects.

Side chain oxidation and cleavage of precursors in cholic acid synthesis is thought to involve initial hydroxylation at either position 25 or 26 of the side chain. Therefore, the conversion of 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 26-tetrol and 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 25-tetrol into cholic acid was studied in normal subjects after single intravenous injections of these labeled alcohols. Eighty-six percent and 82% of 5 beta-cholestane, 3 alpha, 7 alpha, 12 alpha, 26-tetrol was converted into cholic acid in two subjects, respectively. However, only 14 and 16% of the injected 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 25-tetrol was converted into cholic acid in two subjects, respectively. Thus, this study indicates that 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 25-tetrol is an inefficient substrate for cholic acid biosynthesis in man and that the major route of cholic acid synthesis probably involves the 26-hydroxylated intermediate.     

Structural elucidation of some orange juice carotenoids

The structure of some carotenoids of Valencia orange juice were elucidated by chemical tests and MS of the free pigments and their derivatives. A new apocarotenal was shown to be 3-hydroxy-5,8-epoxy-5,8-dihydro-8′-apo-β-caroten-8′-al. Two UV-fluorescent apocarotenols found recently in avocado were also present. For the pigments previously designated trollixanthin and trollichrome, the new structures 5,6-dihydro-β,β-carotene-3-3′,5,6-tetrol and 5,8-epoxy-5,8,5′,6′-tetrahydro-β,β-carotene-3,3′,5′,6′-tetrol are assigned, both containing a trihydroxylated ring as in heteroxanthin.     

Identification of bile alcohols in human bile

Human gallbladder bile was examined for bile alcohols. Following isolation and hydrolysis, the bile alcohols were analyzed by capillary gas-liquid chromatography-mass spectrometry. The following bile alcohols were identified with certainty by direct comparison with reference standards: 5 beta-cholane-3 alpha,-7 alpha,23,24-tetrol; 5 beta-cholane-3 alpha,7 alpha,12 alpha,24-tetrol; 24-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,25-tetrol; 27-nor-5 beta-cholest-25-ene-3 alpha,7 alpha,-12 alpha,24-tetrol; 3 alpha,7 alpha,12 alpha-trihydroxy-27-nor-5 beta-cholestan-24-one; 27-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25-pentol; 27-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25,26-hexol; 5 beta-cholestane-3 alpha,7 alpha,24-triol; 5 beta-cholestane-3 alpha,7 alpha,25-triol; 5 beta-cholestane-3 alpha,7 alpha,26-triol; 5 alpha-cholestane-3 alpha,7 alpha,12 alpha,24-tetrol; 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24-tetrol; 5 beta-cholestane-3 alpha,7 alpha,12 alpha,25-tetrol; 5 beta-cholestane-3 alpha,7 alpha,12 alpha,26-tetrol; (24R)- and (24S)-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25-pentols; 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,26-pentol; 5 beta-cholestane-3 alpha,7 alpha,12 alpha,-25,26-pentol; 5 beta-cholestane-3 alpha,7 alpha,12 alpha,26,27-pentol; 26-methoxy-5 beta-cholestane-3 alpha,7 alpha,12 alpha,25-tetrol. There also existed two norcholestanetetrols and three cholestanetetrols with two hydroxyl substituents on the nucleus and two in the side chain. The human biliary bile alcohols occurred mainly as sulfate esters and in lesser amounts as glucuronoconjugated and unconjugated forms. The amount of total bile alcohols was about 0.9 mg (0.7-1.2 mg) in 1 g of bile solid, or 0.16 mumol (0.07-0.24 mumol) in 1 ml of gallbladder bile.     

Chemical synthesis of 5beta-cholestane-3alpha, 7alpha, 24, 25-tetrol and its metabolism in the perfused rabbit liver

5beta-[G-3H]Cholestane-3alpha, 7alpha, 24xi, 25-tetrol (IV) was synthesized via dehydration and peroxidation of 5beta-[G-3H]cholestane-3alpha, 7alpha, 25-triol. Following perfusion of the labeled compound in the isolated rabbit liver, the bile alcohol and bile acid metabolites secreted into the bile were identified by a combination of thin layer chromatography, gas-liquid chromatography, and gas-liquid chromatography/mass spectrometry. The following bile alcohols were tentatively identified: 5beta-cholest-23-ene-3alpha, 7alpha, 25-triol, 5beta-cholest-25-ene-3alpha, 7alpha, 12alpha, 24xi-tetrol, and 5beta-cholestane-3alpha, 7alpha, 12alpha, 24xi, 25-pentol. The amount of administered tetrol recovered unchanged ranged from 1 to 88%. Cholic acid was the major product, but limited amounts of chemodeoxycholic acid were also formed. The 24-hydroxyl group in the steroid side chain did not prevent 12alpha-hydroxylation.     

A new triterpene glucoside from Cymbidium giganteum

A new triterpene glucoside, cymbidoside, has been isolated from Cymbidium giganteum. Its structure is shown to be 4ξ-(β-d-glucopyranosyloxymethyl)-14α-methyl-22ξ, 24ξ, 25,28-tetrahydroxy-9,19-cyclo-5α,9β-ergostan-3-one.     

Structural and biosynthetic studies of a principal bile alcohol, 27-nor-5beta-cholestane-3alpha,7alpha,12alpha,24,25-pentol, in human urine

The stereochemistry at C-24 and C-25 of 27-nor-5beta-cholestane-3alpha,7alpha,12alpha,24 ,25-pentol, a principal bile alcohol in human urine, and its biosynthesis are studied. Four stereoisomers of the C(26)-24,25-pentols were synthesized by reduction with LiAlH(4) of the corresponding epoxides prepared from (24S)- or (24R)-27-nor-5beta-cholest-25-ene-3alpha, 7alpha,12alpha,24-tetrol. The stereochemistries at C-25 were deduced by comparison of the C(26)-24,25-pentols with the oxidation products of (24Z)-27-nor-5beta-cholest-24-ene-3alpha,7alpha, 12alpha-triol with osmium tetraoxide. On the basis of this assignment, the principal bile alcohol excreted into human and rat urine was determined to be (24S,25R)-27-nor-5beta-cholestane-3alpha,7alpha, 12alpha,24,25-pentol, accompanied by a lesser amount of (24R, 25R)-isomer. To elucidate the biosynthesis of the C(26)-24,25-pentol, a putative intermediate, 3alpha,7alpha, 12alpha-trihydroxy-27-nor-5beta-cholestan-24-one, derived from 3alpha,7alpha, 12alpha-trihydroxy-24-oxo-5beta-cholestanoic acid by decarboxylation during the side-chain oxidation of 3alpha,7alpha, 12alpha-trihydroxy-5beta-cholestanoic acid, was incubated with rat liver homogenates. The 24-oxo-bile alcohol could be efficiently reduced to yield mainly (24R)-27-nor-5beta-cholestane-3alpha,7alpha, 12alpha,24-tetrol. If a 25R-hydroxylation of the latter steroid occurs, it should lead to formation of (24S,25R)-C(26)-24,25-pentol. Now it has appeared that a major bile alcohol excreted into human urine is (24S,25R)-27-nor-5beta-cholestane-3alpha,7alpha, 12alpha, 24, 25-pentol, which might be derived from 3alpha,7alpha, 12alpha-trihydroxy-27-nor-5beta-cholestan-24-one via (24R)-27-nor-5beta-cholestane-3alpha, 7alpha,12alpha,24-tetrol.     

Dinoflagellate sterols IV: Isolation and structure of 4α,23ξ,24ξ-trimethylcholestanol from the dinoflagellate Glenodiniumhallii

The dinoflagellate $\text{Glenodinium}$$\text{hallii}$ was investigated for its sterol composition. Five of the six sterols were isolated and identified as cholest-5-en-3β-ol, (24ξ)-24-methylcholest-5-en-3β-ol, stigmasta-5,22-dien-3β-ol, (22E,24R)-4α,23,24-trimethyl-5α-cholest-22-en-3β-ol, and 4α,23ξ,24ξ-trimethyl-5α-cholestan-3β-ol.