Decolorizing charcoal

In a 500-cc. round-bottom flask fitted with a reflux condenser are placed 68 g. of phenylurea (0.5 mole) (Note i) and 120 cc. (i mole) of 42 per cent hydrazine hydrate solution (Note 2). The flask is heated on a steam bath for about twelve hours. The hot mixture is treated with a small amount of decolorizing charcoal (Norite) and filtered. The charcoal is washed with two 15-CC. portions of warm water and the filtrate and washings are then concentrated on a steam bath to about 100 cc. On coolipg in an ice bath a crop of crystals separates and is collected on a filter and washed with two 15-cc. portions of cold water. The filtrate and washings are concentrated to about 25 cc. and another crop of crystals is obtained as before. The total yield of crude compound is 47-52 g. It is white at first but sometimes turns brown on drying. It usually melts below 115° because of some unchanged phenylurea. 

The crude acid is dissolved in 300 cc. of hot water, boiled with 4-5 g. of decolorizing charcoal for a few minutes, and the solution filtered. After cooling thoroughly under the tap the purified product is filtered with suction and washed with 10-15 c. of cold water. The purified acid weighs 35-40 g. (70-80 per cent of the theoretical amount) and melts at 211-212°. 

Benzyltrimethylammonium hydroxide (Triton B) [100-85-6] M 167.3, d 0.91. A 38% soln (as supplied) was decolorized (charcoal), then evaporated under reduced pressure to a syrup, with final drying at 75° and 1 mm pressure. Prepared anhydrous by prolonged drying over P2O5 in a vacuum desiccator. 

Propenyl)aniline (1, 1.0 g, 7.52 mmol), PdCl2(CH3CN)2 (0.195 g, 0.75 mmol), benzoquinone (0.812 g, 7.52 mmol), and LiCl (3.158 g, 75.2 mmol) were combined in THF (95 mL). After 5 h at reflux, the solvent was removed and the residue was stirred with ether and decolorizing charcoal for approximately 20 min and filtered. The filtrate was washed five times with 50-mL portions of 1 M NaOH. The solvent was removed by vacuum, and the residue was placed on a silica gel column and eluted with 3 1 petroleum ether/ether. 2-Methylindole (2, 0.818 g, 86%) was collected as a white, crystalline solid, identical with authentic material. ... 

However the acid is prepared, the sodium salt may be prepared as described in U.S. Patent 3,503,967 Five liters of methylene chloride were added to a clean dry vessel equipped with stirrer. 7-[a(4-pyridylthio)acetamido] cephalosporanic acid (1,000 g) was added to the vessel, followed by 350 ml of triethylamine. The resultant solution was treated with decolorizing charcoal for 15 minutes and filtered. A solution of sodium-3-ethyl-hexanoate (27.3%) in butanol-methylene chloride was added to the filtrate with stirring. Seven thousand five hundred milliliters of acetone was added. Crystallization occurred while stirring was continued several hours under dry conditions. The crystals were collected by filtration, washed with large volumes of acetone, and then dried in vacuo at 50°C to yield about 950 g of the title compound. 

The pale yellow product was dissolved in warm, absolute methanol, and the solution after mixing with decolorizing charcoal was filtered through a bed of filter aid. The filter bed was washed with warm absolute methanol, and the combined methanolic filtrate and... 

The crude product separates as a solid from the reaction medium and is recovered by filtration, and it is then washed thoroughly with ether and dissolved in 350 ml 1 N HCI. Then, approximately 250 ml of the aqueous solvent is removed with a rotary evaporator and the evaporation residue combined with 125 ml methanol and filtered through decolorizing charcoal. The product is precipitated as the HCI salt by the addition of 7 parts of acetone. The resulting crystalline material is removed by filtration dried at 40°C with vacuum, and has a melting point of about 242°C and Is used without further purification. 

The 2,3-dichlorophenoxyacetic acid and n-butyryl chloride are placed in the reaction vessel and stirred while the aluminum chloride is added portionwise over a 45-minute period. The mixture then is heated on the steam bath for 3 hours and allowed to cool to room temperature. The gummy product obtained is added to a mixture of 300 ml of crushed ice and 30 ml concentrated hydrochloric acid. The resulting mixture is extracted with ether and the extract evaporated at reduced pressure. The residue Is suspended in boiling water and dissolved by addition of a minimum quantity of 40% sodium hydroxide. After treatment with decolorizing charcoal and filtering, the hot filtrate is made acid to Congo red paper and chilled in ice. 

The oil that separates is extracted with ether, the extract dried over anhydrous sodium sulfate and then evaporated at reduced pressure. The residue is dissolved in boiling benzene (75 ml) treated with decolorizing charcoal, filtered, treated with boiling cyclohexane (275 milliliters) and cooled to give 22.3 grams of 2,3-dichloro-4-butyrylphenoxyacetic acid. After several recrystallizations from a mixture of benzene and cyclohexane, then from methyl-cyclohexane, next from a mixture of acetic acid and water, and finally from methylcyclo-hexane, the product melts at 110° to 111°C (corr). 

After 2 hours the mixture is cooled to about 0°C and the crude product Is collected by filtration, washed with diethyl ether and dried in a vacuum oven. After treatment with decolorizing charcoal and recrystallization from an equivolume mixture of isopropanol and methanol, the product, 2,5-bis(2,2,2-trifluoroethoxy)-N-(2-piperidylmethyl)benzamide hydrochloride has a MP of 228°C to 229°C. 

Preparation of oi-Acetylamino-cx-Carboxy- -(S-Benzyloxy-lndolyl-3j-Propionic Acid 18 grams ethyl o -acetylamino-0 -carbethoxy-/3-(5-benzyloxy-lndolyl-3)-propionate was suspended in 85 ml water containing 8.5 grams sodium charcoal. The suspension was refluxed for 4 hours, decolorizing charcoal added, and the solution filtered hot through Hyflo Super-cel. 

Hydroxycyclopentyl-(o-chlorophenyl)-ketone N-methylimine (2.0 g) Is dissolved in 15 ml of Decalin and refluxed for Th hours. After evaporation of the Decalin under reduced pressure, the residue is extracted with dilute hydrochloric acid, the solution treated with decolorizing charcoal, and the resulting acidic solution is made basic. The liberated product, 2-methylamino-2-(o-chlorophenyl)-cyclohexanone, after crystallization from pentane-ether, has MP 92° to 93°C. The hydrochloride of this compound has MP 262° to 263°C. 

In the final production preparation, a mixture of ethyl methyl(3-benzoylphenyl)cyano-acetate (48 g), concentrated sulfuric acid (125 cc) and water (125 cc) is heated under reflux under nitrogen for 4 hours, and water (180 cc) is then added. The reaction mixture is extracted with diethyl ether (300 cc) and the ethereal solution is extracted with N sodium hydroxide (300 cc). The alkaline solution is treated with decolorizing charcoal (2 g) and then acidified with concentrated hydrochloric acid (40 cc). An oil separates out, which is extracted with methylene chloride (450 cc), washed with water (100 cc) and dried over anhydrous sodium sulfate. The product is concentrated to dryness under reduced pressure (20 mm Hg) to give a brown oil (33.8 g). 

The aqueous acid solution is rendered alkaline by adding 2 N sodium hydroxide solution. After extracting with diethyl ether (3 times 100 cc), drying the extracts over potassium carbonate, treating them with decolorizing charcoal, filtering and evaporating the ether, a yellowish oil (0.9 g), identified as 5-methyl-10-methylamino-10,11 -dihydro-dibenzo[b,f] azepine, is obtained in a yield of 37.5%. 

The reaction mixture is acidified with N hydrochloric acid (200 cc) and the oil formed is extracted with methylene chloride (200 cc). The methylene chloride solution is washed with water (210 cc), treated with decolorizing charcoal (5 grams), dried over anhydrous sodium sulfate and concentrated to dryness under reduced pressure (20 mm Hg) giving an oil (77 grams) which is crystallized from methanol (300 cc) to yield methyl ethyl (7-meth-oxy-10-methyl-3-phenthiazinyl)-malonate (62.4 grams) melting at 80°-82°C. 

The crude 2-(p-nitrobenzenesulfonamido)-pyrimidine from the preceding step was suspended in 130 parts alcohol and 1.5 parts of concentrated hydrochloric acid were added. The suspension was then heated to reflux and 30 parts of iron powder were added with mechanical stirring. The mixture was refluxed and stirred for 24 hours with r"-asional addition of concentrated hydrochloric acid. The reaction mixture was then made slightly basic and filtered hot and the residues were extracted with several portions of boiling alcohol. The filtrate and wash solutions were combined and evaporated. The 2-(sulfanilamido)-pyr-imidine was recrystallized from boiling water with decolorizing charcoal added, according to U.S. Patent 2,410,793. 

The reaction mixture was then poured into 1,650 parts of hot water, the pH adjusted to 8 to 9, decolorizing charcoal was added and the whole was heated on the steam for 15 minutes. The charcoal was filtered off and the hot filtrate neutralized and cooled. The2-(sulfanilamido)-5-ethyl-1,3,4-thiadiazole was purified by repeated crystallization from boiling water. 

The resulting white solid is collected on a filter, air dried, redissolved in 2,500 parts water at 95°C and the resulting solution treated with decolorizing charcoal and clarified by filtration. The cooled filtrate is made alkaline with ammonia and the product, crude 3-(1-piperidyl)-Tcyclohexyl-1-phenyl-1-propanol is collected. The hydrochloride melts with decomposition in ten seconds in a bath held at 258.5°C. The alcohol melts at 114.3° to 115.0°C, according to U.S. Patent 2,716,121. 

Diethyl malonate or a derivative (0.25 mol) and benzene-1,2-diamine (27 g, 0.25 mol) were added to a solution of NaOEt prepared from sodium (11.5 g. 0.5 g-atom) and EtOH (300 mL). The EtOH was distilled off, finally under reduced pressure, and the residue was heated at 180-200 C under N2 for 4 h and then stirred with ice. The mixture was acidified with coned HC1 and the resulting solid was collected, washed with H20 and recrystallized (EtOH) with the addition of decolorizing charcoal if necessary. 

Place about 8 mL of coffee in the unlabeled test tube and add 0.2 g of decolorizing charcoal to the coffee. Put a stopper in the test tube and shake its contents for 2 min. 

This was significant in the preparation of l,2-dimethyl-3-hydroxy-4-pyridone, employed clinically as an iron chelating agent. The aminoreductone is obtained by reaction of methylamine with maltol. Traces of metal within the system readily form highly colored complexes with reactant or product and these are difficult to remove. With the CMR, the preparation was achieved in 65 % yield without the need for decolorizing charcoal and the product was crystallized by collecting the effluent in acetone (Scheme 2.10) [22]. 

The solution is allowed to stand for three days at room temperature, and is then concentrated on the steam bath under reduced pressure (water pump) until spattering makes further evaporation impossible. Two hundred cubic centimeters of water is added to the residue, and the contents of the flask are washed into a small beaker where they are stirred to a smooth slurry. The product is filtered, washed thoroughly on the funnel with cold water, and dried in an oven at 80 90°. The crude material melts at 204-206° and weighs 47-57 g. (80-96 per cent of the theoretical amount). It is purified by recrystallization from 650 cc. of boiling methyl alcohol using 5 g. of decolorizing charcoal. The recrystallized, pale yellow needles of 5-nitroinda-zole melt at 208-209°. The yield is 42-47 g. (72-80 per cent of... 

Methylphenobarbitone. 1 mole of phenobarbitone (232.23 g) is dissolved in 2.5 liters of 95% (not dry) ethanol. To this is added a solution of 45 g NaOH (sodium hydroxide) in 500 ml of 95% ethanol. This mixture is heated, with stirring, until reflux is achieved. 70 g of dimethyl sulphate is added dropwise and refluxing is continued for 3 hours after this addition. Change the reflux condenser into a distillation condenser and distill the ethanol from the mixture. Add water and pour into an ice-hydrochloric acid mixture at 0°. Recrystallize the resulting precipitation, after collection by filtration, from boiling water using decolorizing charcoal. Yield 70% of theoretical, mp 178-181°. 

To a flask equipped with a reflux condenser are added 68 gm (0.5 mole) of phenylurea and 120 ml (1.0 mole) of 42 % hydrazine hydrate solution. The mixture is refluxed for 12 hr, filtered hot using decolorizing charcoal, and then concentrated to 100 ml. On cooling, the crystalline product separates and it is washed with the minimum amount of water. The filtrate is concentrated to 25 ml and another crop of crystals is collected. The total yield of the crude... 

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