Sodium tert-butylate

Bertrand et al. have introduced a stable acyclic a-aminophosphonium salt. Only basic phosphines, such as tris(dimethylamino)phosphine, allow for the synthesis of stable aminophosphonium salts. The species mentioned gave upon deprotonation with butyllithium the corresponding C-amino phosphorus ylide (Scheme 100/1). In contrast, two cyclic a-amino phosphonium salts were found to be stable despite the presence of weakly basic triarylphosphine moieties. The key intermediates were dicationic aldiminium salts that on treatment with sodium tert-butylate afforded the cyclic a-aminophosphonium salts under discussion (Scheme 100/2 and 3). In Scheme 100/2, the carbenoid intermediate involved is also shown. On treatment with LiHMDS or BuLi, the stable phosphonium salts were converted to the corresponding P-ylides (Scheme 100/2 and 3). In the second example, the cyclic ylide was transformed to a phosphinoarylenamine derivative via a carbenoid intermediate (Scheme 100/3). ... 

Prepare anhydrous tert.-butyl alcohol by refluxing the commercial product with sodium ca. 4 g. per 100 ml.) until the metal is about two-thirds dissolved and then distilling. Free metal should be present during the distillation. 

Similarly sodium methoxide (NaOCHj) is a suitable base and is used m methyl alco hoi Potassium hydroxide m ethyl alcohol is another base-solvent combination often employed m the dehydrohalogenation of alkyl halides Potassium tert butoxide [K0C(CH3)3] is the preferred base when the alkyl halide is primary it is used m either tert butyl alcohol or dimethyl sulfoxide as solvent... 

Use curved arrows to track electron movement in the dehydro halogenation of tert butyl chloride by sodium methoxide by the E2 mechanism J... 

The first step is the manufacture of L-proline tert-butyl ester. L-proline (230 g) is dissolved in a mixture of water (1 ) and 5N sodium hydroxide (400 ml). The solution is chilled in an ice bath, and under vigorous stirring, 5 N sodium hydroxide (460 ml) and benzyloxycarbonyl chloride (340 ml) are added in five equal aliquots during a half-hour period. After one hour stirring at room temperature, the mixture is extracted twice with ether and acidified with concentrated hydrochloric acid. The precipitate Is filtered and dried. Yield is 442 g MP 78°C to 80°C. 

The benzyloxycarbonyl-L-proline thus obtained (180 g) is dissolved in a mixture of dichloro-methane (300 ml), liquid isobutylene (800 ml) and concentrated sulfuric acid (7.2 ml). The solution is shaken in a pressure bottle for 72 hours. The pressure is released, the Isobutylene is allowed to evaporate and the solution is washed with 5% sodium carbonate, water, dried over magnesium sulfate and concentrated to dryness in vacuo, to obtain benzyloxycarbonyl-L-proline tert-butyl ester, yield 205 g. 

Bis(3,5-di-tert-butyl-4-hydroxyphenyl) acetone mercaptole, melting at 125°C to 126°C is prepared by employing 2,6-di-tert-butyl-4-mercaptophenol and acetone as starting materials. In one representative procedure, the 2,6-di-tert-butyl-4-mercaptophenol (47.5 g, 0.2 mol) is dissolved in methanol (50 ml) heated at a temperature of 50°C. A catalytic amount of concentrated hydrochloric acid (1 ml) is added, followed by acetone (5S g,0.1 mol). The temperature of the mixture rises to about 60°C, and is maintained at about 60°C to 65°C for 1.5 hours. The mixture is cooled, diluted with water and about 10 ml of aqueous sodium bicarbonate and extracted with ether. The ether extract is evaporated, and the product is obtained as a residue, which is recrystallized from ethanol and then from isopropanol to obtain the bis(3,5-di-tert-butyl-4-hydroxyphenyl) acetone mercaptole as a crystalline solid melting at about 125°Cto 126°C. 

In another representative procedure about 2.3 mols of 2,6-di-tert-butyl-4-mercaptophenol is dissolved in about 1,700 ml of methanol under a nitrogen atmosphere about 100 ml of concentrated hydrochloric acid and 1B0 ml of acetone are added, and the mixture is stirred and maintainedat a temperature of about 35°C to 50°C, for 1.5 hours. The mixture is then cooled to room temperature and filtered, and the bis(3,5-di-tert-butyl-4-hydroxyphenyl) acetone mercaptole product is collected as a colorless crystalline solid filter cake. The product is washed with water and aqueous sodium bicarbonate and purified by recrystallization from ethanol. 

In a 500-cc. separatory funnel are placed 74 g. or 95 cc. (1 mole) of tert-butyl alcohol (Note x) and 247 cc. (3 moles) of c.p. concentrated hydrochloric acid (sp. gr. 1.19). After shaking, the layers are allowed to separate (fifteen to twenty minutes) and the upper layer is drawn off and washed first with a 5 per cent sodium bicarbonate solution, then with water until neutral to moist litmus paper (Note 2). The chloride is treated with 10 g. of calcium chloride and shaken thoroughly, then transferred to a 125-cc. distilling flask. It is then distilled, using a long water condenser. The fraction boiling at 49.5-5 20 weighs 72-82 g. (78-88 per cent of the theoretical amount). 

Exposure of compound 16, a substance that can be obtained in a straightforward manner from glycine, to sodium tert-butoxide furnishes an enolate that undergoes conversion to 8 upon treatment with terf-butyl formate. It was anticipated that the phthalimido and tert-butyl ester protecting groups in 8 could be removed easily and selectively under anhydrous conditions at a later stage in the synthesis. 

Treatment with two equivalents of tert-butyl hypochlorite and subsequent reduction with sodium/naphthalene. 

B. 2-Chloro-3,6-di-tert-butyl-l,4-benzoquirwne. A 2-1. Erlenmeyer flask is charged with a solution of 112 g. (0.385 mole) of 2,3-dichloro-2,5-di-fer<-butylcyclohex-5-ene-l,4-dione in 800 ml. of ether. A solution of 28.4 g. (0.383 mole) of diethylamine (N-ethylethanamine) in 50 ml. of ether is added in one portion to the vigorously swirled flask (Note 5). The reaction is instantaneous, resulting in a voluminous precipitate. The mixture is washed with two 1-1. portions of water and then with 500 ml. of aqueous saturated sodium chloride. The yellow ether solution is dried over anhydrous magnesium sulfate, the drying agent removed by filtration, and the solvent removed on a rotary evaporator to yield 96-97 g. (98-99%) of 2-chloro-3,6-di-ferf-butyl-l,4-benzo-quinone as a yellow oil which is used without further purification (Note 6). 

The sole recent example in this category is the condensation (in hot aqueous ethanolic sodium hydrogen carbonate) of o-phenylenediamine (399) with tA-tert-butyl 2-hydroxy-3-oxo-l,2,6-piperidinetricarboxylate (400) to give tcrt-butyl 3-[3-(tcrt-butoxycarbonyl)-3-(tcrt-butoxycarbonylamino)propyl]-2-quinoxalinecarboxy-late (401) in 87% yield. ... 

This category is exemplified, albeit poorly, in the reaction of 3-methyl-1,2-benzenediamine (405) with tri-ferf-butyl 2-hydroxy-3-oxo-l,2,5-pyrrolidinetricar-boxylate (406) in aqueous ethanolic sodium hydrogen carbonate under reflux for 3 h. This gave, as minor products, an inseparable mixture (in 9% yield) of tert-butyl 3-[2-(ferf-butoxycarbonyl)-2-(ferf-butoxycarbonylamino)ethyl]-5-methyl-2-quinoxalmecarboxylate (407, Q = Me, R = H) and its 8-methyl isomer (407, Q = H, R = Me). ... 

In a related reaction, primary aromatic amines have been oxidized to azo compounds by a variety of oxidizing agents, among them Mn02, lead tetraacetate, O2 and a base, barium permanganate, and sodium perborate in acetic acid, tert Butyl hydroperoxide has been used to oxidize certain primary amines to azoxy compounds. 

The diazo transfer reaction between p-toluenesulfonyl azide and active methylene compounds is a useful synthetic method for the preparation of a-diazo carbonyl compounds. However, the reaction of di-tert-butyl malonate and p-toluenesulfonyl azide to form di-tert-butyl diazomalonate proceeded to the extent of only 47% after 4 weeks with the usual procedure." The present procedure, which utilizes a two-phase medium and methyltri-n-octylammonium chloride (Aliquat 336) as phase-transfer catalyst, effects this same diazo transfer in 2 hours and has the additional advantage of avoiding the use of anhydrous solvents. This procedure has been employed for the preparation of diazoacetoacetates, diazoacetates, and diazomalonates (Table I). Ethyl and ten-butyl acetoacetate are converted to the corresponding a-diazoacetoacetates with saturated sodium carbonate as the aqueous phase. When aqueous sodium hydroxide is used with the acetoace-tates, the initially formed a-diazoacetoacetates undergo deacylation to the diazoacetates. Methyl esters are not suitable substrates, since they are too easily saponified under these conditions. 

B. Benzobarrelene. A dry 1-1., three-necked, round-bottomed flask is equipped with a magnetic stirring bar, a combined gas-inlet tube and rubber septum, a 500-ml. pressure-equalizing dropping funnel, and a reflux condenser connected to a Nujol bubbler. The flask is charged with 500 ml. of dry tetrahydrofuran (Note 14) and 17 g. (0.74 mole) of sodium wire with a diameter of ca. 0.5 mm. The mixture is stirred and heated at reflux under an atmosphere of argon or nitrogen, and 50 ml. of freshly distilled tert-butyl alcohol is added. Immediately afterward a solution of 15 g. (0.051 mole) of... 

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