Acidification, dry

If nitric acid has been used for acidification, dry the dry residue for 3 hours at 105 °C in a drying cabinet. 

Acidification, dry 16, 794 Acidium salts s. Carbonate-acidium salts, Thio-phosphateacidium —... 

Cool the flask in ice, acidify with 10 ml. of cold 1 1-hydro-chloric acid and distil under reduced pressure (water pump) until most of the alcohol is removed. Add water to the residue, extract several times with ether, wash the combined ethereal extracts with N ammonia solution until a test portion gives no precipitate upon acidification. Extract the combined alkahne solutions once with a fresh portion of ether, and add the aqueous solution to an excess of dilute hydrochloric acid the final mixture should still be acidic to Congo red. Collect the crystalhne half-ester by filtration at the pump, wash it with water and dry at 100°. The yield is 14-5 g., m.p. 122-125°. Recrystallise by dissolving in about 40 ml. of warm benzene and adding an equal volume of petroleum ether (b.p. 40- 60°) 13 -5 g. of the colourless half-ester, m.p. 125-126°, are obtained. 

The starting amino acid for nylon-11 is produced from methyl ricinoleate [141 -24-2] which is obtained from castor oil (qv). The methyl ricinoleate is pyrolized to methyl 10-undecylenate [25339-67-7] and heptanal [111-71-7]. The unsaturated ester is hydroly2ed and then converted to the amino acid by hydrobromination, followed by ammoniation and acidification. The CO-amino acid product is a soft paste containing water, which is dried in the first step of the polymeri2ation process. 

Diacetone-L-sorbose (DAS) is oxidized at elevated temperatures in dilute sodium hydroxide in the presence of a catalyst (nickel chloride for bleach or palladium on carbon for air) or by electrolytic methods. After completion of the reaction, the mixture is worked up by acidification to 2,3 4,6-bis-0-isoptopyhdene-2-oxo-L-gulonic acid (2,3 4,6-diacetone-2-keto-L-gulonic acid) (DAG), which is isolated through filtration, washing, and drying. With sodium hypochlorite/nickel chloride, the reported DAG yields ate >90% (65). The oxidation with air has been reported, and a practical process was developed with palladium—carbon or platinum—carbon as catalyst (66,67). The electrolytic oxidation with nickel salts as the catalyst has also... 

On digestion of this solid mass with 1 1. of ice and water, the sodium salt of the enol dissolves in the water, and the unreacted ester is removed by extracting the aqueous layer with two 200-ml. portions of ether (Note 5). The foimyl derivative settles out as an oil upon acidification of the aqueous layer with dilute sulfuric acid. The oil is extracted with three 200-ml. portions of ether, and the ethereal extract is washed several times with water and dried over anhydrous sodium sulfate. The ether is distilled, and, to remove traces of ethyl formate, the oil is heated on a steam bath under a pressure of 20-30 mm. for 1 hour. The remaining yellow formyl derivative weighs 27-29 g. (Note 6). 

Hydrolysis of the ester is achieved by refluxing in aqueous N or 2N NaOH solution until the insoluble ester dissolves. The solution is then cooled, and the alcohol is extracted into a suitable solvent, e.g. ether, toluene or alcohol-free chloroform. The extract is dried (CaS04, MgS04) and distilled, then fractionally distilled if liquid or recrystallised if solid. (The p-nitrobenzoic acid can be recovered by acidification of the aqueous layer.) In most cases where the alcohol to be purified can be readily extracted fi-om ethanol, the hydrolysis of the ester is best achieved with N or 2N ethanolic NaOH or 85% aqueous ethanolic N NaOH. The former is prepared by dissolving the necessary alkali in a minimum volume of water and diluting with absolute alcohol. The ethanolic solution is refluxed for one to two hours and hydrolysis is complete when an aliquot gives a clear solution on dilution with four or five times its volume of water. The bulk of the ethanol is distilled off and the residue is... 

Alternatively, the acid (5g) is refluxed for 2h with 15mL of MeOH and 2mL of 98% H2SO4 (cool when mixing this soln). Pour into 10 volumes of H2O and extract with the minimum volume of CHCI3 to give clear separation of phases. The extract is washed with H2O and dried (CaCl2) and distd. The methyl ester is collected at 77-79°/ mm, m 38-39°. The ester is hydrolysed with the calculated amount of N KOH and refluxed until clear. Acidification with HCl provides the pure acid with 90% recovery. [Org Synth 4 1 1964.] The amide crysts from cyclohexane, m 189°. [Chem Ber 62 1629 1959.]... 

If the condensation product is used before it is dry, a large amount of carbon dioxide is evolved later in the course of the acidification, indicating incomplete utilization of the ethyl acetoacetate. 

According to the submitter, acidification of the combined sodium bicarbonate washings with 10% hydrochloric acid yields a colorless precipitate of 6,7-dimethoxy-3-methylindene-2-car-boxylic acid, which is collected by filtration, washed, and dried yield, 3.4-3.Q g. (14-16%) m.p. 216-218°. 

Estrone methyl ether (100 g, 0.35 mole) is mixed with 100 ml of absolute ethanol, 100 ml of benzene and 200 ml of triethyl orthoformate. Concentrated sulfuric acid (1.55 ml) is added and the mixture is stirred at room temperature for 2 hr. The mixture is then made alkaline by the addition of excess tetra-methylguanidine (ca. 4 ml) and the organic solvents are removed. The residue is dissolved in heptane and the solution is filtered through Celite to prevent emulsions in the following extraction. The solution is then washed threetimes with 500 ml of 10 % sodium hydroxide solution in methanol to remove excess triethyl orthoformate, which would interfere with the Birch reduction solvent system. The heptane solution is dried over sodium sulfate and the solvent is removed. The residue is satisfactory for the Birch reduction step. Infrared analysis shows that the material contains 1.3-1.5% of estrone methyl ether. The pure ketal may be obtained by crystallization from anhydrous ethanol, mp 99-100°. Acidification of the methanolic sodium hydroxide washes affords 10-12 g of recovered estrone methyl ether. 

To a well stirred suspension of 9 g of sodium phenyl acetate and 2.4 g of magnesium turnings in 25 cc of anhydrous ether, a solution of 9.4 cc of isopropyl bromide in 50 cc of anhydrous ether are added. The mixture is refluxed for one hour (during which time propane is evolved) and then 5 cc of cyclopentanone in 25 cc of anhydrous ether are added dropwise. The mixture is then refluxed for one hour and poured over ice water containing some hydrochloric acid. The ether solution is separated and extracted with 200 cc of 5% sodium hydroxide. The alkaline solution on acidification gives the free acid which is filtered off, dried in a desiccator and recrystallized from a mixture of ethylene dichloride and petroleum ether. 

Phenoxyphenyl)Propionic Acid A mixture of 223 grams of 2-(3-phenoxyphenyl)-propionitrile and 400 grams of sodium hydroxide in 1,600 ml of 50% ethanol was refluxed with stirring for 72 hours. After cooling to room temperature, the reaction mixture was poured into ice water. The resulting solution was washed with ether, acidifed with concentrated HCI, and extracted with ether. The ether extract was washed with water, dried over anhydrous sodium sulfate, and evaporated to dryness in vacuo. The residual oil was distilled to yield 203.5 grams (84%) of 2-(3-phenoxyphenyl)propionic acid as a viscous oil BP 168° to 171°C (0.11 mm), no = 1,5742. 

Preparation of Intermediate Compound 2-Methyl-3-o-Tolyl-6-Sulfamyl-7-Chloro-4(3H)-Quinazoiinone Set up a 5-liter 3-necked flask fitted with a stirrer, condenser and a drying tube. To a stirred mixture of 100 g (0.342 mol) of powdered 4-chloro-5-sulfamyl-N-acetylanthranilic acid, 40.2 g (0.376 mol) of o-toluidine and 2.0 liters of dry toluene was added dropwise, over a period of 15 minutes, 21.7 ml (34.1 g) (0.248 mol) of phosphorus trichloride. The mixture was then refluxed for 10 hours. The solid turned somewhat gummy towards the latter part of the first hour. The mixture then became more free flowing as heating was continued. Let stand overnight. The yellow solid was filtered, washed with toluene and dried. The toluene filtrate was discarded. The dried solid was triturated with 1.5 liters of 10% sodium bicarbonate, filtered and the cake washed with water. The filtrate on acidification yielded 11.5 g of the starting acid. The damp product was dissolved in 4,5 liters of 95% ethanol and the solution treated with charcoal and filtered. On cooling filtrate yielded 69.5 g (55.5%) of the title compound, MP 271.5° to 274°C. 

B) A solution of (SM) (330 mg) in trifluoroacetic acid (7 ml) was kept under nitrogen at room temperature for 15 minutes. Ether (100 ml) was added and the precipitate was filtered, washed thoroughly with ether and dried. This material (300 mg) was added in portions to concentrated sulfuric acid (18 ml) cooled at -20°C with vigorous stirring. After 15 minutes a solution of potassium bisulfate in concentrated sulfuric acid (408 mg in 3 ml) was added. The reaction mixture was stirred for 75 minutes at -15°Cand then stored at -7°Cfor 285 minutes. The sulfuric acid solution was poured into cold ether (400 ml) precipitate was filtered, washed with cold ether, and suspended in cold water. Complete solution was then achieved by careful addition of 2N sodium hydroxide. Acidification with N hydrochloric acid led to the precipitation of the desired octapeptide sulfate ester. Yield 200 mg. 

The acid chloride obtained as described above was dissolved in dry acetone (10 ml) and added in a steady stream to a stirred solution of 6-aminopenicillanic acid (1.08 g, 5 mmol) in a mixture of N sodium bicarbonate (15 ml) and acetone (5 ml). After the initial reaction the reaction mixture was stirred at room temperature for 45 minutes, then washed with ether (3 X 25 ml). Acidification of the aqueous solution with N hydrochloric acid (11 ml) to pH 2 and extraction with ether (3 x 15 ml) gave an ethereal extract which was decolorized with a mixture of activated charcoal and magnesium sulfate for 5 minutes. 

To a solution of 516 nig (1 mmol) of the stannane 17 (R = C.H3, 95% ee) in 10 ml of dry DME is added, at — 78 C, 0.62 nlL of 1.6 M BuLi (1 mmol) in hexane. After 5 min gaseous carbon dioxide is bubbled into ihe yellow solution. The reaction mixture decolorizes immediately. After a further 10 min the reaction is quenched with sat. aq NH4C1. The organic layer is extracted with 2N aq NaOll. Acidification of the aqueous layer with 2N aq IICI is followed by extraction with F.t,o, drying over Na,SC)4 and concentration in vacuo yield 193 mg (92%) 95% ec [determined by HPLC-analysis of the amide obtained by derivati/alion with (S)-x-phenylelhylaminc] [a]20 — 37 (r = 1,6, CI1C1,). 

A7M aqueous solution of LiOII-H20 is added to a 0.35 M solution of the sultam 11 in THF and vigorously stirred at 65 "C for 3 — 5d. Evaporation in vacuo, trituration of the residue with CH2CI2 and evaporation of the dried extracts gave sultam R NH. Acidification of the CH2C12 insoluble residue with 2N aq HC1, saturation with NaCl, extraction with CU2C12 and evaporation of the dried (MgS04) extracts gave the crude carboxylic acid 12 which is purified by distillation. 

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