Tert ethers

Solutions of tert.-butylmagnesium chloride and cyclopentylmagnesium chloride in diethyl ether can be prepared in the same way. In these cases also the purity of the chlorides Is of great importance for a successful and smooth conversion into the Grignard reagent. 

To a mixture of 50 ml of dry THF and 0.050 mol of l-tert.-butoxy-2-pentyne (prepared by ethylation of HC-CCH O-tert.-Ci,H9 in liquid ammonia was added 0.055 mol of butyilithium in about 35 ml of hexane in 10 min at -30°C. After stirring for 20 min at -25°C the solution was cooled to -50°C and 0.06 mol of methyl iodide was added in one portion, followed 10 min later by 50 ml of water. The aqueous layer was separated and extracted twice with diethyl ether. The solutions were dried over magnesium sulfate and concentrated in a water-pump vacuum. 

Hate 1. To a suspension of 0.40 mol of lithium amide in 400 ml of liquid NH3 (see Chapter II, Exp. 11) was added 0.30 mol of HCECCH20-tert.-CitHg Subsequently 0.46 mol of CjHsBr was introduced in 30 min. After an additional 1 h the NH3 was removed by placing the flask in a water-bath at 40°C. Addition of water, extraction with diethyl ether and distillation gave C2H C=CCH20-tert.-C,H in more than 85% yield. 

In the flask was placed a solution of 0.44 mol of butyllithium in about 300 ml of hexane. To this solution were added, with coaling below -20°C, 800, 600 and 400 ml of dry diethyl ether (note 1) in the case of R = CH3, C2H5 and tert.-CuHj or Me3Si, respectively. Subsequently 0.46 mol of the alkyne [in the case of R = CH3, C2H5 a cooled (-30°C) solution in 50 ml of diethyl ether] was added in about 10 min, while keeping the temperature below -20 c. The suspension (in the... 

This isomerization, which must proceed through a 1,2,3-trienylanine, is not "contra-thermodynamic", since with a catalytic amount of potassium tert.-butoxide the same result is obtained. Enyne ethers, H2C=CH-CsC-0R, undergo a similar conversion into HCeC-CH=CH-OR upon interaction with alkali metal amides in liquid NH3, followed by hydrolysis . Enyne sulphides, H2C=CH-CsC-SR, and the hydrocarbons H2C=CH-CsC-R (R = or phenyl) give only tars or polymeric products under... 

To a solution of 22 g of K0-tert.-Ci,H9 (see Exp. 4, note 2) in 400 ml of anhydrous liquid ammonia were added 22 g of the bis-ether (note 1). After stirring for 4 h, 20 g of powdered ammonium chloride were introduced in small portions. The ammonia was removed by placing the flask in a water-bath at 40°C, then 200 ml of water were added and five extractions with small portions of redistilled pentane were carried out. The combined extracts were washed with water, dried over magnesium sulfate and then concentrated in a water-pump vacuum. The residue was carefully distilled through a 40-cm Vigreux column, giving the allenic bis-ether,... 

A mixture of 1 g of KO-terfc.0.6 g of HO-tert.-CgHg and 40 ml of dry, pure HHPT was warmed at 40-50°C until all of the solid material had disappeared. The solution obtained was cooled to 15°C and 15 g of the enyne ether (note 1) were added in 2 min. The temperature of the mixture was kept at aa. 25°C and after the addition this temperature was maintained for an additional 10 min. 

A solution of (CH3)3C-CH=C=CLi, obtained by addition at -60°C of 0.20 mol of tert.-butylallene (see Chapter VI, Exp. 2) to a solution of 0.25 mol of ethyllithium in about 200 ml of diethyl ether (see Chapter II, Exp. 1) was warmed to 25°C and held at this temperature for 15 min. Subsequently the solution was cooled to below 0°C and 50 ml of saturated NH,C1 solution were added dropwise with vigorous stirring, keeping the temperature below 2o C. The upper layer v as separated off and the aqueous layer was extracted twice with 25-ml portions of diethyl ether. The combined solutions were dried over a small amount of magnesium sulfate. Slow distillation through a 40-cm Widmer column gave neopentyl acetylene (b.p. 76°C/750 mmHg, 20... 

To a mixture of 0.40 mol of neohexene ( commercially available) and 200 ml of dry diethyl ether 0.35 mol of bromine was added with cooling between -40 and -50°C. The diethyl ether and excess of neohexene were then completely removed by evaporation in a water-pump vacuum.In the second flask was placed a solution of 90 g of commercial KO-tert.-C9H9 (see Chapter IV, Exp. 4, note 2) in 250 ml of DMSO. The dibromo compound was added in five portions during 15 min from the dropping funnel after the addition of each portion the flask was swirled gently in order to effect homogenization. Much heat was evolved and part of the tert.-butylacetylene passed over. After the addition the flask was heated for 30 min in a bath at B0-100°C. 

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 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... 

Use Learning By Modeling to make models of water methanol dimethyl ether and di tert butyl ether Mini mize their geometries and examine what happens to the C—O—C bond angle Compare the C—O bond dis tances in dimethyl ether and di tert butyl ether... 

Acid catalyzed addition of alcohols to alkenes is sometimes used Indeed before Its use as a gasoline additive was curtailed billions of pounds of tert butyl methyl ether (MTBE) was prepared by the reaction... 

Small amounts of tert butyl methyl ether increase the octane rating of gasoline Before environmental concerns placed limits on its use the demand for MTBE exceeded the supply... 

Potassium tert butoxide reacts with halobenzenes on heating in dimethyl sulfoxide to give ten butyl phenyl ether... 

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