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Query: UMLS:C0338671 (Steroids)
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The chemical synthesis of 24,25-dihydro[32-14C]lanosterol is described. The incubation of this material with a cell-free system from Saccharomyces cerevisiae or with a microsomal preparation from rat liver resulted in both cases in the release of [14C]formic acid. This result suggests that in the biosynthesis of ergosterol in yeast, as well as in that of cholesterol in higher animals, the 14alpha-methyl group of lanosterol is removed as formic acid. In both systems, the measurement of the rate of release of [14C]formic acid from 24,25-dihydro[32-14C]lanosterol provides a simple and direct assay of lanosterol 14alpha-demethylase. Carbon monoxide inhibited both yeast and liver 14alpha-demethylase.
Steroids 1976 Jun
PMID:Lanosterol 14alpha-demethylase. Similarity of the enzyme system from yeast and rat liver. 78 18

Pure performylated bile acids are obtained in quantitative yield by a new formylation procedure. The procedure involves heating the bile acids in 90% formic acid containing catalytic amount of perchloric acid and then adding acetic anhydride slowly until effervescence occurs. Pure performylated bile acids are then isolated simply by diluting the reaction mixture with water. Contrary to what was believed by past investigations, the formyl groups on these compounds are quite stable to various reaction conditions. The stability and ready availability of these compounds make them more suitable candidates than their counterpart--bile acid acetates for use as starting material in various synthetic schemes, such as C-24 labeled bile acids, etc. The partial deformylation of these formates can be effected by using methanolic ammonia, sodium methoxide in methanol, or sodium hydroxide in aqueous acetone. The resultiing 3-hydroxy formyl bile acids are obtained in high yield and are the best starting materials for the synthesis of bile acids with specific modification at 3-hydroxyl group, such as the synthesis of bile acid 3-monosulfates and 3-monoglucuronides.
Steroids 1977 May
PMID:Formylated bile acids: improved synthesis, properties, and partial deformylation. 89 31

5beta-Cholestane-3alpha, 7alpha, 25-triol and 5beta-cholestane-3alpha, 7alpha, 25-24(14-C)-triol were synthesized from 3alpha, 7alpha-dihydroxy-5beta-cholanoic acid (chenodeoxycholic acid). Chenodeoxycholic acid was converted to the diformoxy derivative (II) using formic acid. Reaction of II with thionyl chloride yielded the acid chloride which was treated with diazomethane (CH-2-N-2 or 14-CH-2-N-2) to produce 3alpha, 7alpha-diformoxy-24-oxo-25-diazo-25-homocholane (III, A or B). 25-Homochenodeoxycholic acid (IV, A or B) was formed from III by means of the Wolff rearrangement of the Arndt-Eistert synthesis. The methyl ester of V (A or B) was treated with methyl magnesium iodidi in ether to provide the desired triol, VI (A and B). The triol was identified by mass spectrometry and elemental analysis and was characterized by thin-layer and gas-liquid chromatography. The 3alpha, 7alpha, 25-triol is of possible significance as an intermediate in the pathway of bile acid formation from cholesterol.
Steroids 1975 Mar
PMID:New bile alcohols--synthesis of 5beta-cholestane-3alpha, 7alpha, 25-triol and 5beta-cholestane-3alpha, 7alpha, 25-24 (14C)-triol. 114 73

The conversion of a molecule of 19-oxoandrost-4-ene-3,17-dione [1a] to estrone [2a] by human placental aromatase requires a molecule of oxygen and of NADPH. An atom of this molecule of oxygen is incorporated into the extruded formic acid derived from C-19 of [1a]. It was proposed that the O2 is utilized for the enzymatic 2 beta-hydroxylation of [1a] and the released intermediate 2 beta-hydroxy-19-oxoandrost-4-ene-3,17-dione [5a] aromatized nonenzymatically. Should [5a] be an obligatory intermediate of estrogen biosynthesis, then all the oxygen of its 2 beta-hydroxyl must be incorporated into the extruded formic acid. We have previously synthesized [2 beta-18O; 19-3H] [5c] and proved that none of its 2 beta-18O was incorporated in the formic acid extruded in the aromatization. On this basis we concluded that [5a] can not be an obligatory precursor of estrogen biosynthesis. The trapping of radioactive androst-4-ene-2 beta,3 beta,17 beta,19-tetrol in a reductively terminated incubation of a mixture of radioactive androst-4-ene-3,17-dione and [5a] with crude placental aromatase was interpreted as evidence in support of the intermediacy of [5a]. We confirmed that the tetrol can indeed be trapped in the reductively terminated incubations. However, considering that the crude placental enzyme preparation very likely contains numerous activated oxygen species capable of a variety of oxidation reactions, most of which may not be related to estrogen elaboration, and in view of our results quoted above, the origin and the eventual biosynthetic role of the parent compound of the tetrol remains to be determined.
Steroids
PMID:Concerning the pathway from 19-oxoandrost-4-ene-3,17-dione to estrone. 350 12

Homoursodeoxycholic acid and [11,12-3H]homoursodeoxycholic acid were synthesized from ursodeoxycholic acid and homocholic acid, respectively. Ursodeoxycholic acid (Ia) was converted to 3 alpha, 7 beta-diformoxy-5 beta-cholan-24-oic acid (Ib) using formic acid. Reaction of the diformoxy derivative (Ib) with thionyl chloride yielded the acid chloride (II) which was treated with diazomethane to produce 3 alpha, 7 beta-diformoxy-25-diazo-25-homo-5 beta-cholan-24-one (III). Homoursodeoxycholic acid (IV) was formed from the diazoketone (III) by means of the Wolff rearrangement of the Arndt-Eistert synthesis. N-Bromosuccinimide oxidation of homocholic acid (V), which was prepared from cholic acid by the same procedure described above, afforded 3 alpha, 12 alpha-dihydroxy-7-oxo-25-homo-5 beta-cholan-25-oic acid (VI). Reduction of the 7-ketohomodeoxycholic acid (VI) with sodium in 1-propanol gave 3 alpha, 7 beta, 12 alpha-trihydroxy-25-homo-5 beta-cholan-25-oic acid (VII). The methyl ester of 7-epihomocholic acid (VII) was partially acetylated to give methyl 3 alpha, 7 beta-diacetoxy-12 alpha-hydroxy-25-homo-5 beta-cholan-25-oate (VIII) using a mixture of acetic anhydride, pyridine and benzene. Dehydration of the diacetoxy derivative (VIII) with phosphorus oxychloride yielded methyl 3 alpha, 7 beta-diacetoxy-25-homo-5 beta-chol-11-en-25-oate (IX). Reduction of the unsaturated ester (IX) with tritium gas in the presence of platinum oxide catalyst followed by alkaline hydrolysis gave [11,12-3H]homoursodeoxycholic acid.
Steroids 1984 Dec
PMID:Synthesis of homoursodeoxycholic acid and [11,12-3H]homoursodeoxycholic acid. 640 Jan 51

Bile acid amides and oxazolines were synthesized by a sequence of steps involving the reaction of the free bile acid with formic acid to yield the formyloxy derivative, preparation of the formyloxy acid chloride, condensation of the acid chloride with 2-amino-2-methyl-1-propanol to give the amide and, finally, cyclization of the amide with thionyl chloride to give the oxazoline. The oxazolines were characterized by physical constants, thin layer and gas-liquid chromatography and identified by elemental analysis and gas-liquid chromatography-mass spectrometry. Some of the bile acid oxazoline derivatives alter the activity of bacterial 7-dehydroxylases in vitro, and inhibit the growth of certain anaerobic bacteria in pure culture.
Steroids 1982 Dec
PMID:The preparation of bile acid amides and oxazolines. II. The synthesis of the amides and oxazolines of ursodeoxycholic acid, deoxycholic acid, hyodeoxycholic acid and cholic acid. 718 17

The acidic dehydration of 17 alpha-ethynyl-17 beta-hydroxysteroids (1-3) was investigated. On reaction with thionyl chloride, phosphorus oxychloride, and formic acid, the desired dehydration was accompanied by chlorination, Wagner-Meerwein rearrangement, and D-homoaromatic rearrangement. The structure of the product from the transformation of 17 beta-hydroxypregn-20-yne derivative (3) on reaction with formic acid was misjudged. It was regarded as a pregn-16-en-20-yne (10) instead of the actually rearranged D-homoaromatic compound (11). As a consequence, physical data corresponding to this latter structure have been cited in the literature as those of pregn-16-en-20-yne derivative (10). This confusion prompted us to prepare compounds of both types (4, 9, 10, and 11), the characterization of which is here described.
Steroids 1993 May
PMID:Steroids 49. Investigations on the dehydration of 17 alpha-ethynyl-17 beta-hydroxysteroids. 835 74

3-O-Carboxymethylcoumestrol was prepared as the hapten for immunoassay by a partial alkylation of coumestrol with ethyl chloroacetate in acetone alkalized with potassium carbonate. 3-O-Ethoxycarbonylmethylcoumestrol was separated by column chromatography and finally was hydrolyzed with formic acid. 1H and 13C NMR data (APT, COSY, HMQC, and HMBC) revealed that the reaction was regioselective, as 3-O-ethoxycarboxymethylcoumestrol was the only monosubstituted derivative. The hapten was then conjugated to bovine serum albumin and used for immunization of rabbits. A radioimmunoassay (RIA) system was established based on the polyclonal antiserum and a 125I-labeled hapten-tyrosine methyl ester conjugate as the radioligand. Parameters of the RIA: sensitivity: 12 pg per tube, 50% intercept: 140 pg per tube, working range: 20-4000 pg per tube. The cross-reactivity of a panel isoflavonoid and lignan phytoestrogens was either negligible (e.g. formononetin 0.07%; biochanin A 0.06%) or not detectable at all. The major immunoreactive peak in HPLC fractions from an alfalfa extract had the same retention time as coumestrol standard and represented 94.8% of the signal. The remaining 5.2% of immunoreactivity was distributed between five minor peaks. We conclude that after the validation for particular matrices, the method will be a useful tool for analysis of coumestrol, especially in low volume and low concentration samples.
Steroids 2003 Dec
PMID:Synthesis of hapten and conjugates of coumestrol and development of immunoassay. 1464 76

A rapid, sensitive, and specific method using liquid chromatography tandem mass spectrometry (LC/MS/MS) has been developed for simultaneous determination of testosterone (T), dihydrotestosterone (DHT), estradiol (E2), and 5alpha-androstan-3alpha, -17beta-diol (3alpha-Diol) within human testicular fluid. Sample pretreatment involved a one-step extraction with diethyl ether. The analytes were separated on a Waters X-Terra C18 (150 mm x 2.1 mm i.d., 3.5 microm) analytical column with acetonitrile/water mobile phase (70:30, v/v) containing 0.1% formic acid using isocratic flow at 0.15 ml/min for 8 min. The column effluent was monitored by tandem mass spectrometry with electrospray positive ionization. Linear calibration curves were generated over the range of 0.1-50 ng/ml for T, 0.02-1 ng/ml for DHT, 0.05-2 ng/ml for E2, and 0.2-10 ng/ml for 3alpha-Diol, with values for the coefficient of determination of >0.99. The overall extraction efficiency was greater than 86% for T, 75% for DHT, 66% for E2, and 60% for 3alpha-Diol. The values for within-day and between-day precision and accuracy were <15%. We measured each of the four steroids in testicular sample volumes of only 20 microl, obtained by percutaneous testicular aspiration. The mean intratesticular testosterone concentration found by LC/MS/MS, 572 +/- 102 ng/ml, was similar to that previously obtained by radioimmunoassay (RIA). The mean intratesticular estradiol concentration was 15.7 +/- 2.3 ng/ml, which also correlated well with RIA measurement. Both DHT and 3alpha-Diol were below the limits of detection by RIA, but could be measured accurately by LC/MS/MS. In conclusion, LC/MS/MS represents a sensitive and accurate means by which to measure four separate steroids within small volume samples of testicular fluid.
Steroids
PMID:Simultaneous determination of steroid composition of human testicular fluid using liquid chromatography tandem mass spectrometry. 1557 24

We present a fast and reproducible method for steroid analysis (corticosterone, deoxycorticosterone, progesterone, 17alpha-hydroxyprogesterone, 11-deoxycortisol, 21-deoxycortisol, androstenedione, testosterone, dihydrotestosterone and cortisol) in small volumes of serum and in dried blood spot samples by LC-MS/MS. No derivatisation was needed. LC separation was achieved by using an Atlantis C18 column and water-methanol-formic acid gradient as a mobile phase and a flow rate of 250 microL/min over a run time of 6 min. Steroids were measured in MRM mode with electrospray interface (positive ion mode). Validation showed excellent precision, sensitivity, recovery and linearity with coefficients of determination r2>0.992.
 ...
PMID:Fast and direct quantification of adrenal steroids by tandem mass spectrometry in serum and dried blood spots. 1805 79


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