Reactant, recrystallization

Methoxy-D-Homo-estra-l,3,5(10)-trien-17a-one (96)" (/) Acetic acid (6.4 ml) is added to a stirred solution of estrone methyl ether (93 1.1 g) in ethanol (35 ml) containing potassium cyanide (6 g) at 0°. After being stirred for 1 hr at 0° and 2.5 hr at room temperature, the reactants dissolve and potassium acetate preciptates. Water (65 ml) is added to the reaction mixture and the precipitated solid is collected by filtration. The crude product is dissolved in ethyl acetate and the ethyl acetate solution is washed with water, dried over anhydrous magnesium sulfate and evaporated to dryness under reduced pressure. Recrystallization of a portion of the crude product from cyclohexane-acetone gives 3-methoxy-17a-cyano-estra-l, 3,5(10)-trien-17j5-ol (94a) as needles mp 158.5°. 

The formation of quaternary salts from benzyl halides and related compounds occurs readily and has been known for many years. More recently, Krohnke and co-workers, who have studied the reactions of many heterocyclic quaternary salts, reported the formation of 5 from pyridine and benzylidene dibromide on heating the reactants together for 1 hr at 100°. The salt is sufficiently stable to be recrystallized from methanol containing a trace of hydrogen bromide. Isoquinoline gives a similar salt. 

A mixture of o-methoxyphenol (57 g), glycidol (32 g) and pyridine (1 g) is warmed to 95°C at which temperature a vigorous reaction takes place. The reaction mixture is cooled to prevent the temperature rising above 110°C. When the exothermic reaction has subsided the reactants are heated at 95°C for one hour longer and then distilled under low pressure. The main fraction boils in the range 176°C to 180°C/0.5 mm. It crystallizes on cooling. Recrystallization from benzene gives the pure product, MP 78.5°C to 79.0°C. 

Preparation of J-Sulfanilamido-S-Methylisoxazole 2 grams of 3-acetylsulfanilamido-5-methylisoxazole was heated with 10 cc of an aqueous sodium hydroxide solution on a water-bath for one hour and after cooling the reactant was acidified by addition of acetic acid. The precipitate thus formed was recrystallized from dilute alcohol to give 15 grams of colorless prisms of 3-sulfanilamido-5-methylisoxazole, melting point 167°C. 

The kinetic behaviour of metal salts of oxyacids may be influenced by water of crystallization. Where complete-dehydration precedes decomposition, the anhydrous material is the product of a previous rate process and may have undergone recrystallization. If water is not effectively removed, there may at higher temperature be the transient formation of a melt prior to decomposition. The usual problems attend the identification of partial or transient liquefaction of the reactant in the mechanistic interpretation of kinetic data. 

Otsuka et al. (107) describe [Ni(CNBu )2], as a reddish brown microcrystalline substance, which is extremely air-sensitive. It can be recrystallized from ether at —78°C, and is soluble in benzene in the latter solution the infrared spectrum (2020s, br, 1603m, 1210m) and proton NMR (three peaks of equal intensity at t8.17, 8.81, and 8.94) were obtained. Neither analytical data nor molecular weight is available on this complex. The metal-ligand stoichiometry is presumably established by virtue of the molar ratio of reactants and by the stoichiometries of various reaction products. 

To a mixture of 138.1 g. (1 mole) of salicyclic acid and 128.6 g. (1 mole) of -chlorophenol in a 2-1. round-bottomed flask fitted with a thermometer reaching to the bottom of the flask and a reflux condenser with a drying tube (Note 1) is added 58.3 g. (0.38 mole) of phosphorus oxychloride. The mixture is heated with occasional swirling, and the temperature is maintained at 75-80°. At the end of 4 hours the reactants have been reduced to a molten mass, and this is poured slowly, with vigorous stirring, into a solution of 120 g. of sodium carbonate in 800 ml. of water. The precipitated ester is collected on a filter and washed with four 200-ml. portions of water. The yield of crude, air-dried, p-chloro-phenyl salicylate is 174-189 g. (70-76%) m.p. 65-66°. Recrystallization from absolute ethanol yields 136-154 g. (55-62%) of pure product m.p. 69.5-70.5°. A second crop may be obtained by concentration of the filtrate from the first crop or by the addition of water (Note 2). 

To a solution of 13 g 2,5-dimethoxy-4-(n)-propylbenzaldehyde in 100 mL nitromethane, there was added 1.3 g anhydrous ammonium acetate and the mixture held at reflux for 1 h. Removal of the solvent/reactant under vacuum yielded a spontaneously crystallizing mass of orange solids that was removed with the help of a little MeOH. After filtering and air drying there was obtained 7.5 g 2,5-dimethoxy-B-nitro-4-(n)-propylstyrene with a mp of 118-122 °C. Recrystallization from CH3CN gave an analytical sample with a mp 123-124 °C. Anal. (C13Hl7N04) N. 

Basic alumina (13 g) was added to a mixture of methyl 4-formylbenzoate Id (1.00 g, 6 mmol) and acetophenone 2 (0.48 g, 4 mmol) at room temperature. (When the reactants were solid, a minimum amount (2x3 mL) of dichloro-metliane was used to dissolve them prior to the addition of the alumina.) The reaction mixture was then agitated at room temperature for 2.5 h using a Fisher vortex mixer. The product was extracted into dichloromethane (5x15 mL). Removal of the solvent, under reduced pressure, yielded the solid product. Further purification (removal of traces of benzyl alcohol and aldehyde) was carried out by recrystallization from a petroleum ether-ether mixture to afford l-phenyl-3-[4-(carbomethoxy)phenyl]-2-propen-1-one 3d (4-carbomethoxychalcone), mp 119— 120 °C (81%). 

To a solution of aldimine 1 (0.01 mol) in acetone, added ethyl-a-mercapto/a-cya-noacetate (0.01 mol) followed by basic alumina (20 g) with constant stirring. The reaction mixture taken in a beaker, was thoroughly mixed and the adsorbed material was dried in air. The adsorbed reactant in the beaker was placed in an alumina bath and subjected to microwave irradiation for 1-2 min. On completion of the reaction as followed by TLC examination, the mixture was cooled to room temperature and the product was extracted into acetone (3x15 mL). Recovering of solvent under reduced pressure yielded the product, which was purified by recrystallization from the mixture of ethanol-acetone. 

Basic alumina (18 g) was added to the solution of ethyl bromoacetate 2 (0.01 mol) in dichloromethane (20 mL) and to the solution of potassium thiocarbamate 1 (0.01 mol) in hot acetone (5 mL) at room temperature in two separate beakers. Adsorbed material was dried and the two reactants mixed properly using a mortar and pestle. The reaction mixture was kept inside an alumina bath and irradiated in a microwave oven for 100-110 s. The mixture was cooled and the product was extracted into CH2C12 (5x4 mL). The product was collected by evaporating the solvent and recrystallizing from a mixture of methanol and CH2C12. 

In a Pyrex cylindrical reactor adapted to the Synthewave system, 10 mmol of FDM (1.28 g) were mixed with 25 mmol of alkyl halide, 2 mmol of Aliquat 336 (0.8080 g) and 25 mmol of powdered KOH (1.6 g, containing about 15% of water). The mixture was then homogenized and submitted to monomode micro-waves with mechanical stirring for the adequate time. At the end of the reaction, the mixture was cooled down to room temperature and diluted with 20 mL of methylene chloride or diethyl ether. The solution was filtered (KOH in excess, generated salts). The filtrate was then concentrated and poured dropwise into 300 mL of methanol under intense stirring. The diethers 2 precipitate, therefore free from excess of reactants, catalyst and monoethers which are all soluble in methanol. After filtration and drying under vacuum, the product was recrystallized from adequate solvent. 

Realizing that protonation steps are important, reductions of 69 were performed in diglyme-0.5% H20. Like in DMF, in the absence of catalyst the potential was —3.10 V and the simple alcohol 71 was the only product (86%). The DMP+ mediated reduction, however, was different in this solvent. It took place at the same potential —2.70 V (SCE), but the reactant was consumed after only 1 F mol-1 and the correspoonding pinacol 72 was the only product (60% after repeated recrystallizations). 

N-o-Bromobenzyl-N,N-dimethylamine (lOOg) and ethyl p-toluenesulfonate (94 g) were mixed and warmed to 50°-60°C after standing for either (a) a minimum of 96 hours at 15°-20°C or (b) a minimum of 18 hours at 50°-60°C and cooling to room temperature, a hard, crystalline mass was formed. Recrystallization of this product from acetone (2.0 ml/g of crude solid), followed by filtration and drying to 60°C gave N-o-bromobenzyl-N-ethyl-N,N-dimethylammonium p-toluenesulfonate as a white, crystalline solid, MP 97°-99°C. For this procedure it was necessary that the reactants were substantially colorless and of a high purity. 

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