Evaporator rotatory

To a freshly prepared solution of 11.3 g. (0.10 mole) of hydrox-ylamine-O-sulfonic acid (Note 1) in 64 ml. of cold water there is added 24 ml. (24 g., 0.30 mole) of pyridine (Note 2). The mixture is heated at about 90° on a steam bath for 20 minutes. It is then cooled to room temperature with stirring, and 13.8 g. (0.10 mole) of potassium carbonate is added. The water and excess pyridine are removed from the mixture by heating it at 30-40° in a rotatory evaporator in conjunction with a water aspirator. The residue is treated with 120 ml. of ethanol, and the insoluble precipitate of potassium sulfate is removed by filtration. 

The rotatory evaporator was washed with ethanol and ether. Bromination on a smaller scale can be carried out in a three-necked, round-bottomed flask with a thermometer, argon inlet, and stirring bar. External cooling with a water bath to keep the internal temperature between 15° and 20°C is important. The use of more concentrated solutions should be avoided, since dimerization instead of bromination becomes the dominant reaction. 

The organic layer was separated and the aqueous layer was extracted with ether (3 x 30 mL). The combined organic layer was washed with brine, dried over magnesium sulfate, filtered and concentrated using a rotatory evaporator to give a crude black residue. 

The solvent was removed using a rotatory evaporator, and the resulting residue was diluted with ether (50 mL). The diamine was extracted with 10% phosphoric acid (3 x 15mL), after which the aqueous layer was made alkaline (pH 9) with 10 % sodium hydroxide solution (100 mL). The resulting mixture was extracted with ether (5 x 50 mL). The combined ethereal extracts were dried over anhydrous potassium carbonate, filtered and concentrated in vacuo to afford the pure (f ,i )-l,l -bis [a-(dimethylamino) propyl]ferrocene as an orange solid (11.4 g, 98.0%). 

The dichloromethane was removed by rotatory evaporation and dry ether (30 mL) was added. The mixture was stirred vigorously for 15 minutes and then acidified with IN HC1 (15mL). 

The work-up was done by dropwise addition of ice-cold water (50 mL caution gas evolution ). The reaction mixture was diluted with dichloromethane (lOOmL) and washed with saturated potassium carbonate solution (2 x 50 mL) and brine (2 x 50 mL). The organic layer was dried over magnesium sulfate, filtrated and concentrated using a rotatory evaporator. 

After no further gas evolution could be detected, the reaction mixture was poured into saturated ammonium chloride solution (150 mL) and transferred into a separatory funnel. The aqueous layer was extracted with t-butyl methyl ether (3 x 70 mL), the combined organic layers were washed with water (2 x 100 mL) and brine (100 mL) and dried over magnesium sulfate. After filtration the solvent was removed using a rotatory evaporator (bath temperature <30 °C) to give a yellow oil. 

The reaction was monitored by H-NMR. When complete conversion was obtained, the solvent was removed and the crude reaction was filtered through a short silica gel column using t-butyl methyl ether as eluent. The resulting solution was concentrated using a rotatory evaporator to give N-acetylphenylalanine methyl ester in quantitative yield as a white solid. 

The submitters used the following conditions rotatory evaporator bath temperature 35°C, cooling water temperature -5°C pressure 500 mbar. 

B. 2-Methoxycyclooctanone oxime. In a 500-ml., three-necked, round-bottomed flask, fitted with a mechanical stirrer, a dropping funnel, and a reflux condenser equipped with a calcium chloride tube, is placed a solution of 53.5 g. (0.252 mole) of crude 2-chlorocyclooctanone oxime hydrochloride in 250 ml. of methanol. While cooling the vessel with running water, 60.7 g. of triethyl-amine (0.60 mole) is added dropwise during 40 minutes. The reaction temperature is kept below 50° and the reaction is continued for 30 minutes with stirring. After removal of methanol under reduced pressure using an efiicient rotatory evaporator, a light brown semisolid is obtained it is treated with 200 ml. of ether and 200 ml. of water to effect complete solution. The ether layer is separated and the aqueous layer is further extracted twice with ether. The combined ether solution is washed with saturated sodium chloride and dried over sodium sulfate. Removal of ether affords 42.8 g. of crude 2-methoxycyclooctanone oxime (Note 3) as a brown oil. 

Typical procedure. A mixture of the carbonyl compound (0.01 mol), the active methylene compound (0.01 mol) and tellurium(lV) tetrachloride (0.001 mol) was thoroughly mixed at room temperature. After being stirred for 5 min, the mixture was heated and continuously stirred at 80°C in an oil bath (20-75 min). The reaction was cooled at room temperature and treated with a solution of 1% aqueous alcohol. The product was extracted with methylene chloride, washed with water. After drying over Na2S04 the solvent was removed in vaccuo over rotatory evaporator to obtain the product in high purity. 

Typical procedure. Benzaldehyde (0.53 g, 5 mmol) was dissolved in methanol (15 mL), tellurium powder (1.276 g, 10 mmol) and KOH (1.40 g, 25 mmol) were added and the reaction mixture was stirred. The reaction became vigorous immediately after the addition of KOH. The reaction mixture was filtered to remove the tellurium powder and water (50 mL) was added to the filtrate. A solid precipitated out which was filtered off under pressure. Some of the diol was obtained by extracting the filtrate with CH2CI2 (3x20 mL), drying with anhydrous Na2S04 and then concentrated using a vacuum rotatory evaporator. 

Typical procedure A mixture of the benzyl ether (0.246 g, 1 mmol) and p-phe-noxyphenyltellurium trichloride (0.403 g, 1 mmol) in anhydrous chloroform (15 ml) was stirred for 30 min at room temperature, then the solvent was evaporated and the residue was filtered through a column of silica gel eluting with chloroform. Evaporation of the solvent in a rotatory evaporator followed by recrystallization of the residue from chloro-form/petroleum ether and washing several times with petroleum ether gave 0.50 g (97%) of the product, m.p. 108-110°C. 

Telluraxanthene Bis(2-bromophenyl)methane (3.33 g, 1.02 mmol) is dissolved in 300 tuL of absolute diethyl ether and, under dry nitrogen, 22 mL (36.1 mmol) of a 15% solution of n-butyllithium in hexane are added dropwise. The mixture is heated under reflux for 0.5 h, cooled to 20°C and 1.8 g (14.1 mmol) of finely powdered tellurium are added. The resultant mixture is heated under reflux for 2 h and then poured into ice/water. The mixture is extracted with chloroform, the extract is filtered and the solvent is evaporated in a rotatory evaporator at 20°C under aspirator vacuum. The residue is recrystallized from diethyl ether/petroleum ether after addition of activated charcoal. Yield 1.42 g (47%) m.p. 151°C. 

Oxidation of Elaidic Acid Ozonization Products. Elaidic acid was ozonized in chloroform solution (5.0 grams in 100 ml.) at 0°C., and the solvent was removed by rotatory evaporation at room temperature. Aliquots were oxidized catalytically and noncatalytically as described above. 

The filtrate from the conversion of the [BCS]- salt to the chloride salt contains H[BCS], which is readily recovered as follows The filtrate ( 400mL) is concentrated to a volume of 80 mL in a rotatory evaporator, whereby most of the ethanol is removed. Concentrated ammonia (12 M, 34 mL) is added to the aqueous and strongly acidic solution to give pH 8. Precipitation of NH4[BCS] commences almost immediately and the mixture... 

To a solution of benzaldehyde (1.06g. lOmmol) in CH2CI2 (10ml) were added trimethylsulfonium methyl sulfate (2.17 g, 11.5 mmol) and 50% aqueous NaOH (5 ml). The reaction mixture was magnetically stirred at room temperature for 2.5 h. Water (20-30 ml) was added and the organic phase was decanted. The aqueous phase was extracted twice with ether (2 X 20ml). The combined organic solution was washed twice with water and dried (CaCl2). The solvents were evaporated under vacuum (rotatory evaporator, cold bath) and the epoxide distilled (l-2g, 80%), b.p. 82°C/38 torr. 

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