Magnesium tert-butyl- chloride

The combined acid layers are distilled from a 250-cc. Claisen flask connected to an air condenser, which in turn is connected to a side-arm flask cooled by running water. The trimethylacetic acid is collected at i62-i6s°/a-tm. press., no-ii2/ i24mm. The yield, which depends somewhat on the form of magnesium, is 157-162 g. (61-63 Per cent of the theoretical amount based on tert-butyl chloride) when ordinary magnesium turnings are used and 177-178 g. (69-70 per cent) when 200-mesh magnesium powder is used. The acid melts at 34-350. 

If unreacted magnesium remains at this time, more tert-butyl chloride is introduced in order to achieve complete conversion to the Grignard reagent. 

To a solution of 0.40 mol of butyllithium in about 280 ml of hexane were added 300 ml of dry THF at -20 to -40 0. Subsequently 0.40 mol of freshly distilled tert.-butyl propargyl ether was added, keeping the temperature below -30°C. Freshly distilled acetaldehyde (0.40 mol) was then added at the same temperature during about 15 min. The cooling bath was removed and, after an additional 15 min, 200 ml of an aqueous solution of 30 g of ammonium chloride were introduced. After separation of the layers the aqueous layer was extracted twice with diethyl ether and the combined solutions were dried over magnesium sulfate and concentrated in... 

The rate of the reaction decreases with increasing number of substituents in the acetylenic halide, and it is higher with acetylenic bromides than with the corresponding chlorides. Methyl magnesium iodide gives equal amounts of 1,1- and 1,3--substitution products, whereas tert.-butylmagnesium bromide does not react. However, for some tert.-butyl substituted allenes there exists an attractive com-... 

The crude tosylate obtained after evaporation of the diethyl ether was dissolved In 150 ml of THF. After addition of 1 g of CuBr the solution was cooled to -10°C and a solution of tert.-butylmagnesium chloride in 250 ml of THF, prepared from 0.40 mol of -butyl chloride and magnesium (see Chapter II, Exp. 4) was added... 

The directions given in Exp. XXX by the reaction of tert-butyl magnesium chloride and carbon dioxide are an improvement on those described by Bouveault.9... 

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). 

After completion of the reaction (1 hour), the solution was neutralized with dilute hydrochloric acid and the solvent removed in vacuo. The residue was diluted with ethyl acetate and the organic solution was washed with saturated aqueous sodium chloride. The organic layer was dried over magnesium sulfate, concentrated under reduced pressure and distilled to afford tert-butyl 3-hydroxybutyrate (80 %). 

Ethyl 3-oxoalkanoates when not commercially available can be prepared by the acylation of tert-butyl ethyl malonate with an appropriate acid chloride by way of the magnesium enolate derivative. Hydrolysis and decarboxylation in acid solution yields the desired 3-oxo esters [59]. 3-Keto esters can also be prepared in excellent yields either from 2-alkanone by condensation with ethyl chloroformate by means of lithium diisopropylamide (LDA) [60] or from ethyl hydrogen malonate and alkanoyl chloride usingbutyllithium [61]. Alternatively P-keto esters have also been prepared by the alcoholysis of 5-acylated Mel-drum s acid (2,2-dimethyl-l,3-dioxane-4,6-dione). The latter are prepared in almost quantitative yield by the condensation of Meldrum s acid either with an appropriate fatty acid in the presence of DCCI and DMAP [62] or with an acid chloride in the presence of pyridine [62] (Scheme 7). 

One surprising example is how ferric (not ferrous) chloride catalyzes the formation of ketyl radicals in a Gringnard-type reaction between ( 113)3001, Mg, and (0Hj)20=O (Ashby and Wiese-mann 1978). The initially formed tert-butyl magnesium chloride reacts with ferric chloride and gives tert-butyl iron(Ill) dichloride ... 

In a i-l. round-bottomed flask are placed 12 g. (0.5 gram atom) of magnesium powder, 37 g. (0.5 mole) of tert.-butyl alcohol, and 100 g. of anhydrous ether (Note 1). The flask is fitted with an addition tube, one arm of which bears a reflux condenser, and the other arm a dropping funnel. While the mixture is being shaken by hand, a solution of 55 g. (0.7 mole) of acetyl chloride (Note 2) in 50 g. of anhydrous ether is added dropwise (Note 3). A lively reaction gradually ensues with evolution of hydrogen, mixed with ether vapor and a little hydrogen chloride (Note 4). After all the acetyl chloride has been added, the reaction mixture is allowed to stand in a pan of cold water for one hour (Note 5). After another hour at room temperature the mixture is warmed in a water bath at 40-45° for one-half hour in order to complete the reaction. 

The deprotection of t-Boc proline ester 2a is representative of the general procedure employed, tert-Butyl carbamate (0.217 g, 1.0 mmol) and aluminium chloride (0.134 g, 1.0 mmol) doped on a neutral alumina (1.0 g) were mixed thoroughly on a vortex mixer. The reaction mixture was placed in an alumina bath inside an unmodified household microwave oven (operating at frequency 2450 MHz) and irradiated for a period of 1 min. After completion of the reaction (monitored by TLC, EtOAc-hexane, 9 1 v/v), it was neutralized with aqueous sodium bicarbonate solution and the product was extracted into ethyl acetate (2x15 mL). The ethyl acetate layer was separated, dried over magnesium sulfate, filtered, and the crude product thus obtained was purified by column chromatography to afford pure methyl ester 2b in 88% yield. 

Bromo-l-(4-fluorophenyl)-l-(3-dimethylaminopropyl)-l,3-dihydroisobenzofuran Magnesium Butyl lithium tert-Butyl methyl ether Isopropylmagnesium chloride Thionyl chloride Sulfamide Dry ice... 

A solution of 0.634 g (2.0 mmol) of 2-(benzyloxycarbonyl)-decahydro-(4aS,8aS)-isoquinoline-3(S)-carboxylic acid in 6 ml of dimethoxyethane was treated with 0.23 g (2.0 mmol) of N-hydroxysuccinimide and 0.412 g (2.0 mmol) of dicyclohexylcarbodiimide. The mixture was stirred at room temperature for 18 hours. The mixture was filtered and the filtrate was evaporated to give 0.879 g of the N-hydroxysuccinimide ester of the foregoing acid in the form of a pale yellow oil. A solution of 0.828 g (2.0 mmol) of the foregoing N-hydroxysuccinimide ester in 5 ml of dichloromethane was stirred, cooled to 0°C and treated with 0.219 g (3.0 mmol) of tert.butylamine. The mixture was stirred at 0°C for 2 h and then at room temperature for 4.5 h. The mixture was then washed with 2 M hydrochloric acid, sodium carbonate solution and sodium chloride solution, dried over anhydrous magnesium sulphate and evaporated. The residue was dissolved in 20 ml of diethyl ether and filtered. The filtrate was evaporated to give 0.712 g of 2-(benzyloxycarbonyl)-N-tert-butyl-decahydro-(4aS,8aS)-isoquinoline-3(S)-carboxamide in the form of a white solid. 

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