Methanol preparation

Tetra-n-butylammonium hydroxide (0.1 M solution in methanol). Prepare an anion exchange column using an anion exchange resin such as Duolite A113 or Amberlite IRA-400, convert to the hydroxide form and after washing with water, pass 300-400 mL of methanol through the column to remove water (see Section 7.2). 

C. (Z)-[2-(Fluoromethylene)cyclohexyl]benzene (3). To a solution of (fluorovinyl)stannane 2 (26.0 g, 0.054 mol) in dry THF (150 mL) is added 65 mL of 1 M sodium methoxide in methanol (prepared by the addition of 1.50 g (0.065 g-atom) of sodium to 65 mL of methanol). The solution is refluxed for 18 hr under nitrogen (Note 14), cooled to ambient temperature and concentrated on a rotary evaporator. The residue is partitioned between water (200 mL) and hexane (200 mL). The aqueous layer is separated and extracted with hexane (100 mL). The combined organic layers are dried (magnesium sulfate) and concentrated on a rotary evaporator to give a colorless oil (30 g). Kugelrohr distillation gives 10.0-10.2 g (97-100%) of fluoro olefin 3 (bp 85-90°C, 0.4 mm) as a colorless oil (Note 15). 

Dimethylxylaramide 1- To a 250 mL round-bottom flask equipped with a magnetic stirrer was added methanol (50 mL) and the xylaric acid - methanol esterification product (6.7 mmol in 10 mL of methanol) prepared as described above. Triethylamine (6.5 mL, 46 mmol) and methylammonium chloride (1.0 g, 14.7 mmol) were then added to the methanol solution and the reaction mixture was refluxed with stirring overnight. The mixture was concentrated and the residue was washed several times with methanol. The... 

Reagents for Enzyme-Immunoassay. Tris buffer contained 0.05 M Tris (hydroxymethyl) aminomethane, pH 7.5 0.05, with 0.1% human serum albumin and 0.01% sodium azide. The H O -methanol fixative contained 0.3% in absolute methanol prepared just before use... 

Methanolic potassium hydroxide solution, 1.0 M Dissolve 11.2 g KOH in 2 ml water Add 100 ml methanol Prepare fresh... 

Aminoacetonitrile. Stir a suspension of 88 g (0.4 mol) of the nitrile sulphate in 100 ml of dry methanol in a 500-ml three-necked flask cooled in crushed ice. Add a few crystals of phenolphthalein as an indicator, pass a slow stream of nitrogen through the flask and run in during 1 hour a solution of sodium methoxide in methanol prepared from 17 g (0.75 mol) of sodium and 350 ml of dry methanol the suspension should at no time be allowed to become permanently alkaline to phenolphthalein. Filter, and remove the methanol and distil the residue under reduced pressure under nitrogen. The yield of aminoacetonitrile, b.p. 73.5°C/15mmHg, is 35 g (83% based on sodium). Store the product at 0 °C under nitrogen. 

Bis[4-methylphenyl] Tellurium Bis[2-(4 -methylbenzylidenamino)phenoxide]4 A solution of sodium methoxi-de in 30 ml absolute methanol, prepared by the addition of 0.95 g (40 mmol) sodium to methanol, is added to a stirred solution of 9.40 g (20 mmol) of bis [4-methylphenyl] tellurium dibromide in 50 ml dry toluene. Methanol is distilled from the reaction mixture until the temperature of the vapors reach 110°. Sodium bromide is removed by filtration, The filtrate, containing his[4-methylphenyl] tellurium dimethoxide, is added to a stirred solution of 8.44 g (40 mmol) of 2-(4-methylbenzylidenamino)phenol in 50 ml dry toluene. Most of the toluene is distilled under vacuum from the reaction mixture. The concentrate ( 30 ml) is mixed with an equal volume of absolute diethyl ether. The mixture is cooled to — 5°. The crystals are collected by filtration and recrystallized from hexane m.p. 135°. 

Methanol Prepare a Sample Solution by diluting 10 mL of sample to 100 mL with water. Prepare a Standard Solution in water containing 40 p.g of methanol in each milliliter. Add 0.2 mL of 10% phosphoric acid and 0.25 mL of 1 20 potassium permanganate solution to 1 mL of each solution. Allow the mixtures to stand for 15 min, then add 0.3 mL of 1 10 sodium bisulfite solution to each, and shake until colorless. Slowly add 5 mL of ice-cold 80% sulfuric acid, keeping the mixtures cold during the addition. Add 0.1 mL of 1 100 chromotropic acid solution, mix, and digest on a steam bath for 20 min. 

Procedure Prepare a series of THI-DNPH Standard Solutions serially diluted from the Stock THI-DNPH Solution. Pipet 1, 2, and 5 mL, respectively, of the Stock THI-DNPH Solution, into separate 10-mL volumetric flasks, and dilute to volume with absolute, carbonyl-free methanol. Prepare a standard curve by injecting 5 p-L of the Stock THI-DNPH Solution, and the serially diluted THI-DNPH Standard Solutions into a 250-mm x 4-mm (id), 10-lm LiChrosorb RP-8 HPLC column (Alltech Associates, Inc., or equivalent) fitted with an ultraviolet detector set at 385 nm. The mobile phase is 50 50 (v/v) methanohO.l M phosphoric acid. Inject 5 pL of sample into the column. Adjustments in the mobile phase composition may be needed as column characteristics vary among manufacturers. At a mobile phase flow rate of 2 mL/ min and column dimensions of 250 x 4.6 mm, elute THI-DNPH at about 6.3 0.1 min. Measure the peak areas. Calculate the amount of THI in the sample from the standard curve. (For THI limits greater than 25 mg/kg, prepare a series of Standard THI-DNPH Solutions in a range encompassing the expected THI concentration in the sample.)... 

Phenylmethysulphonylfluoride (PMSF) PMSF (5%, w/v) in methanol (prepared fresh each day)... 

Primary and secondary allylic alcohols and saturated secondary alcohols are oxidized to the corresponding carbonyl compounds quickly and in high yield at room temperature in DMF. There is no appreciable overoxidation of allylic alcohols in DMF, but primary saturated alcohols are readily oxidized to their corresponding acids. Recently, it has been reported that aldehydes may be converted to methyl esters by oxidation with PDC in the presence of methanol. Preparation of other esters, or methyl esters direct from the alcohol, proved to be less efficient. 

Ferric perchlorate reagent. Stock 8.5 g of ferric perchlorate is dissolved in 20 ml of water and then made up to 250 ml with 72-73% perchloric acid. Working 45 ml of stock solution is added to 755 ml of absolute methanol prepare just before use... 

Although 1.2 g of AsPhj does not dissolve in 20 mL of MeOH at room temperature, it dissolves in boiling methanol. One may add instead a AsPh, slurry in methanol prepared at room temperature to the warm concentrated reaction mixtiTre. It will have practically no effect on the yield of the complex. 

Transfer buffer 10 mM CAPS in 10% methanol. Prepare 2 liters by mixing 200 ml of the CAPS stock solution with 200 ml of methanol and 1600 ml... 

Triacetyl-4-thio-6-azauridine added to a soln. of hydroxylamine in methanol prepared from hydroxylamine hydrochloride and Na-methoxide, refluxed 3.5 hrs., and allowed to stand overnight at room temp. -> N -hydroxy-6-azacytidine. Y 84%. V. Cerneckij et al.. Coll. 27, 87 (1962). 

Sulfuric acid-methanol Prepare a 50% solution of H2SO4 in methanol spray and heat plates for several minutes at 100°C Brown-black spots on a colorless background... 

Reconstitution solution 90 10 water methanol. Prepare with Type 1 water. 

Mobile Phase A (MP-A) 5 mM ammonium formate buffer, pH 4.5 + 2% methanol. Prepare this stock using the lOx buffer listed above in LC-MS grade water. Use LC-MS grade methanol. Check pH of this reagent before use decant a small amount into a beaker, and then discard after testing pH. Do not insert the pH meter into the main buffer container as this may result in contamination of the mobile phase with salts that can interfere with MS detection. 

Acyl lipids are transesterified very rapidly in anhydrous methanol in the presence of a basic catalyst. Free fatty acids are not normally esterified, however, and care must be taken to exclude water from the reaction medium to prevent their formation as a result of hydrolysis of lipids. 0.5 M Sodium methoxide in anhydrous methanol, prepared simply by dissolving fresh clean sodium in dry methanol, is the most popular reagent, but potassium methoxide or hydroxide have also been used as catalysts. The reagent is stable for some months at room temperature, especially if oxygen-free methanol is used in its preparation. The reaction is very rapid phosphoglycerides, for example, are completely transesterified in a few minutes at room temperature. It is commonly performed as follows ... 

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