Steroids neutral

Steroids (neutral or conjugated) and their dansylhydrazine derivatives Polyacrylic gel-based macroporous particles Acetonitrile-water-240 mM ammonium formate buffer, pH 3 (55 40 5) (also gradient elution) 350 mm x 100 pm i.d. 250 mm active length, laser induced fluorescence detection or coupling with electrospray-ion-trap mass spectrometry... 

Figure 5.13 Column Kinetex CIS 2.6 p,m (150 x 3.0 mm) mobile [iiase acetonitrile-water 47-53 (v/v%) flow 1.8 ml/min (p = 516 bar) column temperature 60°C injection volume l xl detection 215 nm analytes steroids (neutral polar API) swabbed from stainless steel model surface. From Olah, E., et al. J. Chwmatogr. A. 2010, with permission.

Allyl aryl ethers are used for allylation under basic conditionsfh], but they can be cleaved under neutral conditions. Formation of the five-membered ring compound 284 based on the cyclization of 283 has been applied to the syntheses of methyl jasmonate (285)[15], and sarkomycin[169]. The trisannulation reagent 286 for steroid synthesis undergoes Pd-catalyzed cyclization and aldol condensation to afford CD rings 287 of steroids with a functionalized 18-methyl group 170]. The 3-vinylcyclopentanonecarboxylate 289, formed from 288, is useful for the synthesis of 18-hydroxyestrone (290)[I7I]. 

The tetrahydrothiopyranyl ether was prepared from a 3-hydroxy steroid and dihy-drothiopyran (CF3COOH, CHCI3, 35% yield) it can be cleaved under neutral conditions (AgN03, aq. acetone, 85% yield). ... 

Steroids The applied steroids are reduced by means of a mixture of 10% ethanolic sodium borohydnde solution and 0 1 N sodium hydroxide solution (1-1-1) The excess reagent is neutralized with aad after 30 min [3]... 

Protonation of the a-carbanion (50), which is formed both in the reduction of enones and ketol acetates, probably first affords the neutral enol and is followed by its ketonization. Zimmerman has discussed the stereochemistry of the ketonization of enols and has shown that in eertain cases steric factors may lead to kinetically controlled formation of the thermodynamically less stable ketone isomer. Steroidal unsaturated ketones and ketol acetates that could form epimeric products at the a-carbon atom appear to yield the thermodynamically stable isomers. In most of the cases reported, however, equilibration might have occurred during isolation of the products so that definitive conclusions are not possible. 

In a 250 ml Erlenmeyer flask covered with aluminum foil, 14.3 g (0.0381 mole) of 17a-acetoxy-3j5-hydroxypregn-5-en-20-one is mixed with 50 ml of tetra-hydrofuran, 7 ml ca. 0.076 mole) of dihydropyran, and 0.15 g of p-toluene-sulfonic acid monohydrate. The mixture is warmed to 40 + 5° where upon the steroid dissolves rapidly. The mixture is kept for 45 min and 1 ml of tetra-methylguanidine is added to neutralize the catalyst. Water (100 ml) is added and the organic solvent is removed using a rotary vacuum evaporator. The solid is taken up in ether, the solution is washed with water and saturated salt solution, dried over sodium sulfate, and then treated with Darco and filtered. Removal of the solvent followed by drying at 0.2 mm for 1 hr affords 18.4 g (theory is 17.5 g) of solid having an odor of dihydropyran. The infrared spectrum contains no hydroxyl bands and the crude material is not further purified. This compound has not been described in the literature. 

The reactions are generally run at room temperature or below. With steroids the product is usually isolated by addition of the reaction mixture to water followed by filtration or extraction. The inorganic product of the reaction, chromium III, is soluble in neutral or aqueous acid solutions and can be removed by washing. When steroidal amines are oxidized, the work-up is usually modified such that the steroid may be extracted from the insoluble basic chromium III salts. °... 

A total of 3 g (0.13 moles) of sodium hydride is added to a solution consisting of 10 g of 17 -hydroxy-5a-androstan-3-one (36 mmoles) in 200 ml of benzene and 10 ml of ethyl formate. The reaction mixture is allowed to stand under nitrogen for 3 days followed by dropwise addition of 10 ml of methanol to decompose the excess of sodium hydride. The solution is then diluted with 300 ml water and the layers are separated. The basic aqueous solution is extracted with ether to remove neutral material. The aqueous layer is acidified with 80 ml of 3 A hydrochloric acid and the hydroxymethylene steroid is extracted with benzene and ether. The combined organic extracts are washed with water and saturated sodium chloride solution and then dried over magnesium sulfate and concentrated. The residue, a reddish-yellow oil, crystallized from 10 ml of ether to yield 9.12 g (83%) of 17 -hydroxy-2-hydroxymethylene-5a-androstan-3-one mp 162-162.5°. Recrystallization from chloroform-ether gives an analytical sample mp 165-165.5° [a]o 53° (ethanol) 2 ° 252 mjj. (g 11,500), 307 m u (e 5,800). 

The homolysis of tertiary hypochlorites for the production of oxy radicals is well known." The ease with which secondary hypohalites decompose to ketones has hampered the application of hypohalites for transannular reactions. However the tendency for the base-catalyzed heterolytic decomposition decreases as one passes from hypochlorites to hypobromites tohypoidites. Therefore the suitability of hypohalites for functionalization at the angular positions in steroids should increase in the same order. Since hypoidites (or iodine) do not react readily with ketones or carbon-carbon double bonds under neutral conditions hypoiodite reactions are more generally applicable than hypochlorite or hypobromite decompositions. 

Hydrolysis of 6p,l9-Oxido-3a,5a-cyclo steroids.A solution of 0.1 g of 3a,5a-cyclo-6)5,19-oxidocholestane in 20 ml of acetone is treated with 1.0 ml of water and 0.5 ml of 1 N sulfuric acid. After standing for 2 hr at room temperature, the solution is neutralized with saturated sodium bicarbonate solution and extracted with ether. The combined ether extracts are washed with water and concentrated to dryness under reduced pressure. Recrystallization of the crude product from methanol yields 85 mg choIest-5-ene-3, 19-diol mp 147-149° [aj —30°. 

Preparation of A -Pregnadiene-9a-Fluoro-11, 16a,17a,2l-Tetrol-3,20-Dione A solution of 100 mg of A -pregnadiene-9a-fluoro-11, 16a,17a,21-tetrol-3,20-dione 16,21-diacetate was dissolved in 10 ml of methanol and cooled to 0°C. After flushing with nitrogen, a solution of 35 mg of potassium hydroxide in 2 ml of methanol was added to the steroid solution. After standing at room temperature for 1 hour, the solution was neutralized... 

DDQ had been used extensively in the dehydrogenation of 3-keto steroids under neutral or... 

Longevialle, P. Better, R. Electron Impact Mass Spectra of Bifunctional Steroids. The Interaction Between Ionic and Neutral Fragments Derived From die Same Parent Ion. Org. Mass Spectrom. 1983,18, 1-8. 

Numerous workers have demonstrated the applicability of electrospray ionization mass spectrometry (ESI/MS) for the detection and analysis of biomolecules with highly electronegative groups (reviewed by Wood et al., 2003, and for neutral steroids by Higashi and Shimada, 2004). The sensitivity of detection of neurosteroids can also be enhanced by derivatization when they are analyzed by nano-electrospray/mass spectrometry procedures. Neurosteroid sulfates can be easily prepared in a single-step reaction in pyridine with the N,N-dimethylformamide complex of sulfur trioxide (Chatman et al., 1999). Another elegant... 

Higashi T, Shimada K. 2004. Derivatization of neutral steroids to enhance their detection characteristics in liquid chro-matography-mass spectrometry. Anal Bioanal Chem 378 ... 

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