Potassium hydroxide in aqueous acetone

Methyl-l,3-cyclohexanedione has been prepared by cycliza-tion of ethyl 5-oxoheptanoate5 and methyl 5-oxoheptanoate3 with sodium ethoxide and sodium methoxide, respectively, and by methylation of dihydroresorcinol5 employing sodium methoxide in methanol,3 potassium hydroxide in aqueous methanol,7 potassium methoxide in methanol,8 potassium hydroxide in aqueous acetone, potassium carbonate in aqueous acetone,4 or sodium ethoxide in ethanol.10 The present method is essentially that of Stetter,7 except that the unnecessary isolation of the intermediary dihydroresordnol is omitted, and this greatly enhances the ease of preparation. 

This reaction has been used as a method of converting amines to ketones. By carrying out the elimination with potassium hydroxide in aqueous acetone (to trap the aldehyde coproduct) containing methanol or dimethylformamide, Dinizo and Watt were able to obtain ketones in yields of 40-80%. The scheme may be summarized as follows ... 

Berberinephenolbetaine (121) was first obtained by Pyman and designated as neoxyberberine (79). Acetoneberberine (119) was oxidized with potassium permanganate in aqueous acetone to give neoxyberberine acetone (120), the structure of which was established by Iwasa and Naruto (80). On treatment with hydrochloric acid followed by sodium hydroxide, 120 gave 121 (79-81), which was also obtained directly from 119 by oxidation with potassium permanganate or osmium tetroxide (Scheme 26) (80). 

For example, acetone sensitized photocyclization of 16 ° resulted in smooth conversion to 17 in 85% yield. Exposure of the hexacyclic compound 17 to silver(I) tetrafluoroborate in chloroform at room temperature resulted in a very slow [ 2 -I- 2 ] transposition. However after refluxing for 5-7 days with intermittent introduction of small additional quantities of silver(I) tetrafluoroborate, followed by removal of the silver salts by filtration through silica gel and recrystallization from ethanol gave a diazasnoutene derivative 18 in 80% yield, which on treatment with excess potassium hydroxide in aqueous ethylene glycol at 100°C afforded semibullvalene (l9)3 -308 in 65-70% yield. ... 

Dimethylaminomethylindole (gramine). Cool 42 5 ml. of aqueous methylamine solution (5 2N ca. 25 per cent, w/v) contained in an 100 ml. flask in an ice bath, add 30 g. of cold acetic acid, followed by 17 -2 g. of cold, 37 per cent, aqueous formaldehyde solution. Pour the solution on to 23 -4 g. of indole use 10 ml. of water to rinse out the flask. Allow the mixture to warm up to room temperature, with occasional shaking as the indole dissolves. Keep the solution at 30-40° overnight and then pour it, with vigorous stirring, into a solution of 40 g. of potassium hydroxide in 300 ml. of water crystals separate. Cool in an ice bath for 2 hours, collect the crystalline solid by suction flltration, wash with three 50 ml. portions of cold water, and dry to constant weight at 50°. The yield of gramine is 34 g. this is quite suitable for conversion into 3-indoleacetic acid. The pure compound may be obtained by recrystaUisation from acetone-hexane m.p. 133-134°. 

The solubihty of potassium permanganate in aqueous potassium hydroxide (108) is shown in Figure 7. Permanganates are soluble in certain nonaqueous solvents such as hquid NH, but not in hquid SO2. Organic solvents such as glacial acetic acid, acetone, acetonitrile, tert-huty alcohol. 

The crude diol (47)(3.8 g) is dissolved in 160 ml of methanol, mixed with 4 g of potassium hydroxide in 10 ml of water and 20 ml of methanol, and warmed under nitrogen for 5 min. Acetic acid (4 ml) is added and the solution is poured into an aqueous solution of sodium chloride. The product is extracted 3 times with ethyl acetate and the extracts are washed with 10% sodium bicarbonate and then with water. The solvent is removed by distillation and the residue is recrystallized from acetone-petroleum ether to give 1.85 g of (48) mp 275-277°. 

For the liberation of N-methylethylamine, a 1-1. Claisen flask is equipped with a 250-ml. separatory funnel and an efficient condenser for distillation. The receiver is cooled with a mixture of acetone and dry ice (Note 7). A solution of 100 g. (2.5 moles) of sodium hydroxide in 100 ml. of water is added to the flask and kept at about 100° by heating on a steam bath. The aqueous solution of N-methylethylamine hydriodide is added to this solution through the separatory funnel in the course of 1.5 hours. After the addition is complete, the final solution is heated for an additional 30 minutes. Crude N-methylethylamine, b.p. 30-70°, collects in the cooled receiver. It is purified by distillation from 25 g. of solid potassium hydroxide in a 250-ml. modified Claisen flask fitted with a 25-cm. Fenske column and a receiver cooled by dry ice and acetone. N-Methylethylamine is collected at 34-35° weight 49-55 g. (83-93%) 2 3 4 5d 1.3830. 

The early use of aqueous potassium hydroxide in acetone for the acetylation and benzoylation of 3-nitrocarbazole using the acid chlorides has been subsequently repeated for the N-acetylation of 3,6-dinitrocarbazole with acetic anhydride, for the N-acetylation, ethoxycarbonylation, 4-fluorobenzoylation, and prop-2-ynoylation of 2-nitrocarbazole and for the methoxy- and ethoxycarbonylation of carbazole itself utilizing the chloroformate esters. 

Carbazole has been converted to 9-tosyl- and 9-methanesulfonyl derivatives using aqueous sodium hydroxide and acetone and pyridine, respectively. A phenylsulfonylation of 3-methylcarbazole utilized potassium tert-butoxide in dimethylformamide, whereas the mesylation and tosyla-tion of 2-nitrocarbazole were carried out with strong aqueous potassium hydroxide in acetone. The best way to phenylsulfonylate carbazole is to use the catalytic two-phase procedure." ... 

The nonhygroscopic compound is found to be very stable and very insoluble, even with boiling, in common solvents such as water, acetone, methylene chloride, hexane, and acetonitrile. However, the compound is found to be soluble in a stoichiometric amount of aqueous potassium hydroxide, in which the 3ip nmr spectrum shows a sharp singlet at —29.3 ppm relative to 85% phosphoric acid. 

Methylation of 2-hydroxy-3-7V-phenylcarbamoylpyrazine with dimethyl sulfate and potassium carbonate in boiling acetone gave l-methyl-2-oxo-3-A -phenylcarbamoyl-1,2-dihydropyrazine and the 3-(A -methyl-Af-phenylcarbamoyl) analogue was prepared likewise (1055). Similar methylation of 2-hydroxy-3-(o-methylaminophenyl)pyrazine produced 1 -methyl-3-(o-methylaminophenyl)-2-oxo-1,2-dihydropyrazine (1055). A series of 24iydroxy-3-(a-hydroxybenzyl)pyrazines has been methylated with dimethyl sulfate in aqueous sodium hydroxide to the 2-methoxy analogues (1045) and 2-benzyl-3,6-dihydroxy-5-methylpyrazine with diethyl sulfate and sodium ethoxide formed 2-benzyl-3,6-diethoxy-6-methylpyrazine (1066). 

A, By heating at melting point B, by refluxing with aqueous potassium hydroxide in ethanol C by refluxing with ammonium hydroxide in acetone D, by refluxing with hydrochloric acid in ethanol. 

The xanthophylls and carotenes of plants are examined conveniently after removal of the chlorophylls by saponification with alkali. For this saponification, add 10 ml of 30% potassium hydroxide in methanol to the centrifuged acetone or methanol extract in the separatory funnel. After 30 min with occasional swirling, add 40 ml of cold petroleum ether (20-40°C)-diethyl ether (1 1) plus 100 ml of 10% aqueous sodium chloride solution. Wash the resultant upper golden-yellow layer with water and take to dryness as above. Prepare the sample solution by dissolving the residue in 1 ml of petroleum ether (60-110°C)-diethyl ether (1 1). This saponification procedure should not be employed with plant extracts containing xanthophylls that are decomposed by alkalies, as are fucoxanthin from diatoms and brown algae and peridinin from dinoflagellates. 

Obtained by glycosidation of 1 -(2,4-dihydroxy-phenyl)-2-(2-fluorophenyl)ethanone with acetobromo-a-D-glu-cose in aqueous acetone containing potassium hydroxide [5418]. 

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