Eluates

Concentrate each of the two solutions (or eluates) to about 20 ml, by distilling off the greater part of the benzene, the distilling-flask being immersed in the boiling water-bath. Then pour the concentrated solution into an evaporating-basin, and evaporate the remaining benzene (preferably in a fume-cupboard) in the absence of free flames, i.e., on an electrically heated water-bath, or on a steam-bath directly connected to a steam-pipe. Wash the dry residue from the first eluate with petrol and then dry it in a desiccator pure o-nitroaniline, m.p. 72°, is obtained. Wash the second residue similarly with a small quantity of benzene and dry pure />--nitroaniline, m.p. 148" , is obtained. Record the yield and m.p. of each component. 

Benzyloxy-6-bromo-4-nitro-JV-(2-propeny])aniline (5.82 g, 16 mmol), tetra-ii-butylammonium bromide (5.16 g, 16 mmol) and titjN (4.05 g, 40 mmol) were dissolved in DMF (15 ml). Palladium acetate (72 mg, 2 mol%) was added and the reaction mixture was stirred for 24 h. The reaction mixture was diluted with EtOAc, filtered through Cclite, washed with water, 5"/o HCl and brine, dried and evaporated in vacuo. The residue was dissolved in CHjClj and filtered through silica to remove colloidal palladium. Evaporation of the eluate gave the product (4.32 g) in 96% yield. 

Intelligent inspection of the relevant distribution coefficients will show whether a separation is feasible and what the most favorable eluant concentration is likely to be. In the columnar mode, an ion, even if not eluted, may move down the column a considerable distance and with the next eluant may appear in the eluate much earlier than indicated by the coefficient in the first eluant alone. A... 

Research has shown that ascorbic acid can be produced from hulls of immature walnuts by extracting the hull with 0.2% sulfur dioxide solutions, and purifyiag the extract by adsorption on and elution from anion-exchange resias (see Ion exchange). Eluates from the anion-exchange step are concentrated, purified by organic solvent fractionations, decolorized, and crystallized (35). 

To eluate an antibiotic from chromatographic columns as a mobile phase such solvents as methanol, ethanol, propanol, acetone, acetonitrile are usually used. Influence of these solvents on ions Eu(III) in a complex with OxTC and Cit has been investigated. It is established, that the used solvents do not reduce I Eu(III) ions, and sometimes they increase I by 16-45 %. 

Dibutylcarbitol [di(ethyleneglycol)dibutyl ether] [112-73-2] M 218.3, b 125-130 /0.1mm, d 0.883, n 1.424. Freed from peroxides by slow passage through a column of activated alumina. The eluate was shaken with Na2C03 (to remove any remaining acidic impurities), washed with water, and stored with CaCl2 in a dark bottle [Tuck J Chem Soc 3202 1957]. 

Hydroxynaphthol Blue tri-Na salt [63451-35-4] M 620.5, m dec on heating, pKE,t <0. Crude material was treated with hot EtOH to remove soluble impurities, then dissolved in 20% aqueous MeOH and chromatographed on a cellulose powder column with propanol EtOH water (5 5 4) as eluent. The upper of three zones was eluted to give the pure dye which was ppted as the monosodium salt trihydrate by adding cone HCl to the concentrated eluate [Ito and Ueno zfna/ysr 95 583 1970. ... 

Sodium 2-mercaptoethanesulfonate (MESNA) [19767-45-4] M 164.2, pKj <0 (SOj ), pK 9.53 (SH). It can be recrystd from H2O and does not melt below 250°. It can be purified further by converting to the free acid by passing a 2M soln through an ion exchange (Amberlite IR-120) column in the acid form, evaporating the eluate in a vacuum to give the acid as a viscous oil (readily dec) which can be checked by acid and SH titration. It is then dissolved in H2O, carefully neutralised with aqueous NaOH, evaporated and recrystd from H2O [7 Am Chem Soc 77 6231 1955]. 

Phospholipids. For the removal of ionic contaminants from raw zwitterionic phospholipids, most lipids were purified twice by mixed-bed ionic exchange (Amberlite AB-2) of methanolic solutions. (About Ig of lipid in lOmL of MeOH). With both runs the first ImL of the eluate was discarded. The main fraction of the solution was evaporated at 40°C under dry N2 and recryst three times from n-pentane. The resulting white powder was dried for about 4h at 50° under reduced pressure and stored at 3°. Some samples were purified by mixed-bed ion exchange of aqueous suspensions of the crystal/liquid crystal phase. [Kaatze et al. J Phys Chem 89 2565 7955.]... 

Phospho-L-threonine (L-threonine-O-phosphate) [1114-81-4] M 199.1, m 194 (dec), [a]p -7.37 (c 2.8, H2O) (pK as above). Dissolve in the minimum volume of H2O, add charcoal, stir for a few min, filter and apply onto a Dowex 50W (H" " form) then elute with 2N HCI. Evaporate the eluates under reduced pressure whereby the desired fraction produced crystals of the phosphate which can be recrystd from H2O-MeOH mixtures and the crystals are then dried in vacuo over P2O5 at 80 . [de Verdier Acta Chem Scand 7 196 7955.]... 

Hydroxy-4-fluoroestr-4-en-3-one is obtained by rechromatography on Florisil of the combined material of the late eluates from the isolation of the 4,4-difIuoride and the mother liquor from the recrystallization of the latter. Elutions with 1 1 methylene dichloride-ether yield 0.41 g of crude monofluoride mp 143-146°. Recrystallization from hexane-acetone affords 0.29 g of pure monofluoride mp 147-148° [aJo 49° (CHCI3) X 248 m i ( , 15,000). 

To a solution of 0.5 g of lithium aluminum hydride in 35 ml of ether is added 0.2 g of the A -cyanoaziridine. The mixture is heated at reflux temperature for 3.5 hr, cooled, and treated with excess saturated sodium sulfate in water. Filtration and evaporation of the ethereal filtrate gives 0.18 g of a glass which is chromatographed on 10 g of basic alumina (activity III). The benzene-petroleum ether (1 3) eluate gives 0.12 g of 2a,3a-imino-5a-choles-tane, mp 117.5-118.5°, after crystallization from methanol. 

To a mixture of ethyl 5a-cholestan-3-one 2a-xanthate (2 g, 3.95 mmol) and 100 ml methanol is added sufficient ether to completely dissolve the solids. Sodium borohydride (90 mg, 2.36 mmol) is added directly to the reaction flask and the solution is stirred at room temperature for 4 hr. (The use of an excess of sodium borohydride and an extended reaction time produces 5oc-cholestan-2a,3a-thiirane.) The reaction is diluted with 200 ml ether and washed several times with ca. 100 ml water, dried (MgS04) and the solvent is removed under vacuum. The crude sticky gum is chromatographed on a column of 85 g silicic acid. The hexane eluates contain 5a-cholest-2-ene. Ethyl 5a-cholestan-3a-ol 2a-xanthate is obtained in ca. 30% yield by subsequent elution with benzene hexane (1 7) and the desired ethyl 5a-cholestan-3 -ol 2a-xanthate is eluted with ether hexane (1 3) in ca. 30% yield. 

Methoxy-cis-19-norpregna-l,3,5(10),17(20)-tetraene A solution of 31 g (109 mmolesi of estrone methyl ether in 600 ml of benzene is added rapidly to a solution of 469 mmoles of ethylidenetriphenylphosphorane in 1.2 liters of DMSO. After heating under nitrogen at 60° overnight, the reaction is cooled, poured into ice water, and extracted with three portions of hexane, backwashed with three portions of water and the hexane removed. The crude product, dissolved in petroleum ether (bp, 30-60°), is filtered through 225 g of alumina (activity I). The residue from the eluate consists of 95 % cis- and 5 % tran5-isomers, as determined by vpc analysis. After recrystallization from ether-methanol, 26.3 g (82%) of cw-isomer is obtained mp 76.5-77.5° [a]o 60°. 

Rechromatography of the residue from the first benzene eluates (1.57 g) gives an additional 0.37 g of crude (20 R)- and 0.91 g of crude (20S)-18, 20-cyclo-5a-pregnane-3/5,20-diol 3-acetate. 

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