Bromides, preparation from

To a mixture of 100 ml of THF and 0.10 mol of the epoxide (note 1) was added 0.5 g Of copper(I) bromide. A solution of phenylmagnesium bromide (prepared from 0.18 mol of bromobenzene, see Chapter II, Exp. 5) in 130 ml of THF was added drop-wise in 20 min at 20-30°C. After an additional 30 min the black reaction mixture was hydrolysed with a solution of 2 g of NaCN or KCN and 20 g of ammonium chloride in 150 ml of water. The aqueous layer was extracted three times with diethyl ether. The combined organic solutions were washed with water and dried over magnesium sulfate. The residue obtained after concentration of the solution in a water-pump vacuum was distilled through a short column, giving the allenic alcohol, b.p. 100°C/0.2 mmHg, n. 1.5705, in 75% yield. 

A 3-I. three-necked, round-bottom flask is fitted with a mechanical stirrer through a mercury seal, a reflux condenser and a i-l. separatory funnel. A mixture of 200 g. (r mole) of 2,3-dibromopropene (Org. Syn. 5, 49) and 200 cc. of dry ether is added. The flask is now cooled in an ice bath, the stirrer is started, and one molecular equivalent of cyclohexylmagnesium bromide, prepared from 31 g. of magnesium, 204 g. of cyclohexyl bromide and 400 cc. of dry ether (Note i) is added at such a rate that the mixture refluxes gently (Note 2). The addition takes about one-half to three-quarters of an hour. Two layers are formed and magnesium bromide may or may not separate. 

The reaction of (54) and acetylenedimagnesium bromide, prepared from methylmagnesium bromide and acetylene, gave (55) in excellent yield instead of the expected bis-steroid (57). 

Aj Preparation of (2-Amino-5-ChlorophenyljPhenylmethaneimine (4356 CB) A solution of 228.7 g (1.5 mols) of 2-amino-5-chlorobenzonitrile in 1,800 ml of dry ether is added slowly in the course of about 3.5 hours to a solution of phenyl magnesium bromide prepared from 109 g (4.5 g-atoms) of magnesium turnings and 848 g (5.4 mols) of bromobenzene In 3,600 ml of anhydrous ether, and the mixture then heated under reflux for 15 hours. 

The residue was dissolved in 75 ml of tetrahydrofuran, treated with charcoal, and sodium sulfate and filtered. This solution was added to a solution in 250 ml of tetrahydrofuran of phenyl magnesium bromide prepared from 17.7 ml (0.17 mol) of bromobenzene. This mixture was stirred and heated under reflux for 1 hour. It was then cooled and diluted with 400 ml of ether and sufficient 3N hydrochloric acid to make it acidic. The aqueous phase was separated, adjusted to pH 8 with 3N sodium hydroxide and extracted 3 times with 200 ml of ether. The ether extracts were combined, washed with water and dried over sodium sulfate. The residue left on removal of the ether in vacuo was crystallized from petroleum ether to give 3.3 g of 7-chloro-2,3-dihvdro-1-methyl-5-phenvl-1 H-1,4-benzodiazepine, according to U.S. Patent 3,624,703. 

To a solution of thienyl magnesium bromide prepared from 21.4 g of magnesium and 144 g of 2-bromothiophene are added 39.B g of ethyl 4-dimethylaminocyclohexylcarboxylate. The mixture is ailowed to warm to room temperature and stirred for an additional six hours. The reaction mixture is then decomposed with dilute ammonium chloride solution and extracted with ether. The combined ether extracts are extracted thoroughiy with 10% hydrochloric acid and the acid solution made alkaline with ammonium hydroxide. The aqueous solution is extracted with chloroform which is then washed with water, dried and evaporated to a residue in vacuo. Recrystallization of the residue from hexane yields Oi.O -dithienyl-4-dimethyl-aminocyclohexyl carbinol, melting point 156°C to 157°C after recrystallization from benzene. 

Bromide. A 0.01 M solution of potassium bromide, prepared from the pure salt previously dried at 110°C, is suitable for practice in this determination. The experimental details are similar to those given above for chloride except that no methanol need be added. The titration cell may contain 10.00 mL of the... 

A mixture of 1 g 2,4,6-trimethoxyben2yl trimethylsilyl ether 1578 and ethylmagne-sium bromide, prepared from 1 g ethyl bromide and 0.2 g Mg in 90 mb Et20, is heated under reflux for 30 min to give, on filtration through a layer of silica gel... 

Bis(p-methoxyphenyl) ditelluride (typicalprocedure To a solution of p-methoxyphenyl-magnesium bromide (prepared from p-bromoanisole (5.82 g, 0.0311 mol) and Mg (1.0 g, 0.042 mol) in THF (20 mL)) is added Te shot (3.81 g, 0.0300 mol) at room temperature. The mixture is stirred under reflux for 3 h and then cooled to 0°C and treated with a sam-rated solution of NH Cl (20 mL vigorous evolution of gas). The mixture is filtered through Celite and the solids washed with saturated solution of NH Cl and ether. The organic phase is washed with brine and dried with Na2S04. Evaporation of the solvent and recrystaUiza-tion from CHClj/petroleum ether affords the pure product (5.16 g (75%) m.p. 57-59°C). 

A solution of -1 mol of ethylmagnesium bromide (prepared from 1.10 mol of C2H5Br and Mg as described in ref. 4) in -1000 ml of THF (note 1) is heated to 50 C. Acetylene (note 2) is then introduced at a rate of 300-400 mVmin (flow meter) with vigorous stirring, while keeping the temperature between 50 and 55 C (note 3). The introduction of gas is stopped when the temperature has dropped to between 40 and 45 C (without external cooling). The jelly-like suspension is then heated for an additional 30 min at 50 C with introduction of N2 (300-500 m]/min, note 4)... 

To a solution of/t-chlorophenylmagnesium bromide prepared from 0.29 gm (0.012 gm-atom) of magnesium and 2.1 gm (0.011 mole) of 4-chlorobromo-benzene in 30 ml of anhydrous ether is added 1.1 gm (0.011 mole) of freshly fused anhydrous zinc chloride in 50 ml of anhydrous ether. The resulting solu-... 

The organozinc bromide prepared from ethyl 2-bromoacrylate in the presence of naphthalene can be used for a coupling reaction with a variety of aromatic iodides in quasi-quantitative yields. However, the use of Pd[P(Tol-o)3]2Cl2 as catalyst is required for reactions carried out in the presence of aromatic bromides non substituted or substituted by electron-donating or electron-withdrawing groups. In this case, reactions are performed under reflux in THF. 

Add 4.0 g (4.0 ml) of pure aniline dropwise to a cold solution of ethylmagne-sium bromide prepared from 1.0 g of magnesium, 5.0 g (3.5 ml) of ethyl bromide and 30 ml of pure, sodium-dried ether. When the vigorous evolution of ethane has ceased, introduce 0.02 mol of the ester in 10 ml of anhydrous ether, and warm the mixture on a water bath for 10 minutes cool. Add dilute hydrochloric acid to dissolve the magnesium compounds and excess of aniline. Separate the ethereal layer, dry it with magnesium sulphate and evaporate the ether. Recrystallise the residual anilide, which is obtained in almost quantitative yield, from dilute ethanol or other suitable solvent. 

To a solution of 105.6 g of 2-phenylbutanone-3 in 110 ml ether was added dropwise a solution of methylmagnesium bromide (prepared from 19.4 g magnesium and 94.7 g methyl bromide in 400 ml of ether) for 60-90 min. Then the mixture was refluxed for 1 hour. After cooling to the mixture was added diluted sulfuric acid and then extracted with ether. Organic layer was dries with sodium sulfate. After evaporation of ether the 2-phenyl-3-methylbutanol was distilled, B.P. 116-118°C/20 mm, yield 105 g, nd22 1.5152. 

Baxter and Thorvaldson 2 extended the preceding investigation by making a number of analyses of ferrous bromide prepared from meteoric iron. The results were as follow —... 

A solution of 130 g. (1.08 moles) of allyl bromide in twice its volume of dry ether is added dropwise to an ethereal solution of p-bromo-phenylmagnesium bromide prepared from 1.0 mole (237 g.) of... 

Twenty-one grams (0.125 mole) of o-aminodiphenyl is diazotized in the usual manner [Org. Syntheses Coll. Vol. 1, 136 (1941)]. The solution of the diazonium salt is added to a solution of cuprous bromide prepared from 16 g. of copper sulfate [Org. Syntheses Coll. Vol. 1, 136 (1941)]. After evolution of nitrogen ceases, the mixture is made alkaline with sodium hydroxide and steam-distilled. The organic product is removed from the distillate by extraction with ether. After drying, the ethereal solution is distilled. There is obtained 18.7 g. (67%) of o-bromodiphenyl, boiling at 160°/11 mm. 

Phenyl Phenylseleno Tellurium 0.79 g (5 mmol) of benzeneselenol are dissolved in 5ml of anhydrous tetrahydrofuran. Under nitrogen, 2.6 ml of 2 molar ethyl magnesium bromide (5.2 mmol) in diethyl ether are added, the mixture is heated under reflux for 2 h, cooled to 0°, and a solution of phenyl tellurium bromide, prepared from 1.02 g (2.5 mmol) of diphenyl ditellurium and 0.40 g (2.5 mmol) of bromine in tetrahydro-furan/benzene, is added. The reaction mixture is then warmed to 20°. stirred at 20" for 30 min, then 40 ml of low-boiling petroleum ether followed by aqueous ammonium chloride solution are added. The organic layer is separated, washed with saturated aqueous sodium chloride, dried with anhydrous magnesium sulfate, filtered, and evaporated. The residue (1.38g) is plaeed on a eolumn containing 120g of silica gel G, the product (Rf 0.60) is eluted with petroleum ether, the eluate is evaporated, and reddish needles are obtained yield 1.13 g (63%) m.p, 48° (petroleum ether). 

Thallium di-a-naphthyl bromide, prepared from magnesium a-naphthyl bromide and thallie chloride, is a fawn, crystalline powder, melting at 272° C. and is completely soluble in cold pyridine, insoluble in toluene. 

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