Potassium hydroxide-water-dioxane

Alternatively, treat a solution of 3 9 g. of the 6is-diazo ketone in 50 ml. of warm dioxan with 15 ml. of 20 per cent, aqueous ammonia and 3 ml. of 10 per cent, aqueous silver nitrate under reflux in a 250 or 500 ml. flask on a water bath. Nitrogen is gently evolved for a few minutes, followed by a violent reaction and the production of a dark brown and opaque mixture. Continue the heating for 30 minutes on the water bath and filter hot the diamide of decane-1 lO dicarboxyhc acid is deposited on cooling. Filter this off and dry the yield is 3 -1 g., m.p. 182-184°, raised to 184-185° after recrystallisation from 25 per cent, aqueous acetic add. Hydrolyse the diamide (1 mol) by refluxing for 2-5 hours with 3N potassium hydroxide (4 mols) acidify and recrystaUise the acid from 20 per cent, acetic acid. The yield of decane-1 10-dicarboxyhc acid, m.p. 127-128°, is almost quantitative. 

For example, direct treatment of red phosphorus with potassium hydroxide in a mixture of dioxane and water with a phase-transfer catalyst (benzyltriethylammonium chloride) allows direct reaction with primary haloalkanes to form the trialkylphosphine oxide in moderate (60-65%) yield.1415 Allylic and benzylic halides are similarly reported to generate the corresponding tertiary phosphine oxides. When the reaction is performed with a,(o-dihalides, cyclic products are generated only with four- and five-carbon chains the third site... 

Nitronium tetrafluoroborate. Acetonitrile, Ammonium carbonate. Potassium carbonate. Diethyl ether, Acetone, Ethyl acetate. Butanol Sulfamic acid, Potassium hydroxide. Ethanol, Nitric acid, Sulfuric acid, Acetone, Isopropyl alcohol Dioxane, Potassium nitrite. Potassium bicarbonate, Tetranitromethane Lead acetate, Sodium azide Sodium azide, Lead acetate. Water... 

A solution of 3p-acetoxy-5a-pregn-16-ene-ll,20-dione (Chamberlin et al., J.Amer. Chem Soc., 1951, 73, 2396) (25.7 g) in dioxan (Analar, 500 ml) was treated with potassium hydroxide (10 g) and water 250 ml and the mixture allowed to stand at room temperature for 1 h. After a further 1 h at 40°C the mixture was diluted with water and the product filtered off. The crude material was dissolved in chloroform and filtered through a column of grade III neutral alumina (100 g). The material obtained was crystallized from acetone-petroleum to give pure 3p-hydroxy-5a-pregn-16-ene-ll,20-dione (17.65 g, 77.5%) as small plates, melting point 217.5°C. 

Properties Fine, white to creamy white crystalline powder odorless. Sensitive to light. Mp 142-146C. May also exist in a polymorphic modification with mp 180-186C. Soluble in acetone, alcohol, chloroform, dioxane, ether, and vegetable oils practically insoluble in water soluble in solutions of sodium hydroxide or potassium hydroxide slightly dextrorotatory in dioxane solution. 

The same basic method has also been used to prepare 4,4-dichlorotricyclo[5.4.1.0 ]dodeca-7,9,11-triene (17). The starting dibromide 16 is heated with potassium hydroxide in methanol/ dioxane, and the crude norcaradiene derivative is treated with dilute perchloric acid in dioxane/ water, giving the product in 88% overall yield. 

Potassium hydroxide solution (5 ml), followed by the halogen compound (0.025 mole), are added to a solution of 2,4-dinitrothiophenol (5 g, 0.025 mole) in Butylcarbitol (diethylene glycol monobutyl ether) (50 ml). In a few cases, when reaction does not occur at once, the mixture is heated at 70° for 10-30 min or, often better, left at room temperature for a considerable time. When reaction is complete, the cold mixture is treated with ice-water, and the product that seperates is collected and recrystallized solvents used were alcohol, 1-butanol, dioxan, benzene, and acetone. 

Peroxides are removed from dioxan by shaking it with zinc(n) chloride22 or by filtration through activated aluminum oxide (as for diethyl ether),14 the acetal by hydrolysis with concentrated hydrochloric acid, and the acetic acid and water by treatment with potassium hydroxide and sodium. 

Purification of dioxan 23 Dioxan (1 1) is boiled under reflux for 7-12 h with 37% hydrochloric acid (13 ml) and water (100 ml) under a stream of inert gas. To remove water and acid, this material is then shaken with solid potassium hydroxide, further quantities of this being added until no more dissolves in the aqueous phase. The organic layer is separated from the aqueous phase and shaken with further solid potassium hydroxide and again separated. This dioxan is boiled under reflux, with exclusion of moisture, with an amount of sodium wire such that some sodium remains clean even after prolonged boiling finally it is fractionally distilled. 

As the VLB diagram (Fig. 16.28) shows, the water/ dioxane azeotrope is separated easily from both water and from the solvent. However, the laboratory techniques used for drying (molecular sieves, barium oxide, magnesium sulphate and potassium hydroxide) are all rather expensive without a recovery system. Chloroform is an effective azeotropic entrainer and its toxicity is not an automatic disqualification because dioxane itself needs to be handled with very great care. 

In addition to water, this solvent is almost invariably contaminated with peroxide and acetaldehyde. For removal of the peroxide impurity, dioxan is treated with tin(II) chloride and then distilled. Subsequently, the above process is repeated with anhydrous potassium hydroxide for removal of the acetaldehyde. Finally, a molecular sieve with a pore size of 0.4 nm may be used to bind traces of water. This procedure is followed again by distillation. In this way the purification of dioxane may be carried out in three steps, with triple distillation. For simplification, refluxing with lithium aluminium hydride may be attempted, followed by distillation which frees the dioxane from all three impurities in one step. 

General. Pyridine is distilled from p-toluenesulfonyl chloride and then from calcium hydride and stored over potassium hydroxide. N,N-Di-methylformamide is distilled from calcium hydride and stored over molecular sieves. Dioxane is distilled from phosphorus pentoxide. Tri-n-butylamine, triethylamine, diphenyl phosphorochloridate, and o- and p-fluorobenzoyl chlorides are distilled before use. Tri-n-butylammonium pyrophosphate is prepared at room temperature according to the method of Moffatt and Khorana and stored at 5°. Paper chromatography is carried out by the descending technique on Whatman No. 1 paper in (A) isobutyric acid-1 M NH4OH (60 40) and (B) 1-propanol-water (7 3). Electrophoresis is carried out on Whatman No. 1 paper at pH 3.5 in 0.035 M citric acid-0.0148 M sodium citrate (1 1). Evaporations are carried out under reduced pressure at bath temperatures below 30°. Phosphate analyses of nucleoside triphosphates are performed by the method of Lowry and Lopez after treatment of approximately 1 / mole of these compounds for 60 min at 22° in 1 ml of Tris chloride at pH 10.4 containing 0.02 mg of alkaline phosphatase of calf intestinal mucosa (type VII, Sigma Chemical Co.). 

Also obtained from p-acetoxybenzoylcarbinol (SM2) by heating with 4% ethanolic potassium hydroxide for 45 min on a water bath (20%). SM2 was prepared from p-acetoxyphenyl diazomethyl ketone (m.p. 109-110°) after treahnent in dioxane with 2 N sulfuric acid at r.t. for 20 min, then at 40° until no more nitrogen evolved [5073],... 

Preparation by hydrolysis of o-acetoxy-a-acetoxy-acetophenone (SM) with aqueous potassium hydroxide solution by gently wanning for 10-15 min on a water bath maintained at 80° (71%). SM was obtained by cupric chloride-catalyzed decomposition of o-acetoxy-a-diazoacetophenone in dioxane solution in the presence of acetic acid (65%, m.p. 161-162°) [5137]. 

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