Methyl, alcohol bromide

Hydroxide ion Methyl bromide Methyl alcohol Bromide ion (nucleophile) (substrate) (product) (leaving group)... 

Methyl bromide Hydroxide ion Methyl alcohol Bromide ion... 

Into a 1500 ml. round-bottomed flask place 97-5 g. of finely-powdered sodium cyanide (1), 125 ml. of water, and a few chips of porous porcelain. Attach a reflux condenser and warm on a water bath until all the sodium cyanide dissolves. Introduce a solution of 250 g. (196 ml.) of n-butyl bromide (Sections 111,35 and 111,37) in 290 ml. of pure methyl alcohol, and reflux gently on a water bath for 28-30 hours. Cool to room temperature and remove the sodium bromide which has separated by filtration through a sintered glass funnel at the pump wash the crystals with about 100 ml. of methyl alcohol. Transfer the filtrate and washings to From n caproamide by SOClj method. 

Place 425 ml. of concentrated ammonia solution (sp. gr. 0-88) in a 500 ml. round-bottomed flask and add slowly 75 g. of a-bromocaproic acid (Section 111,126). Stopper the flask tightly and allow it to stand in a warm place (50-55°) for 30 hours. Filter the amino acid at the pump and keep the filtrate A) separately. Wash the amino acid (ca. 26 g.) well with methyl alcohol to remove the ammonium bromide present. Evaporate the aqueous filtrate (A) almost to dryness on a steam bath. 

A new approach we found is based on the initial bromination of methane to methyl bromide, which can be effected with good selectivity, although still in relatively low yields. Methyl bromide is easily separated from exeess methane, whieh is readily recyeled. Hydrolysis of methyl bromide to methyl alcohol and its dehydration to dimethyl ether are readily achieved. Importantly, HBr formed as by produet ean be oxidatively reeycled into bromine, making the overall proeess cat-alytie in bromine. 

Recall that the term kinetics refers to how the rate of a reaction varies with changes m concentration Consider the nucleophilic substitution m which sodium hydroxide reacts with methyl bromide to form methyl alcohol and sodium bromide... 

Methylal, see Dimethoxymethane Methyl alcohol Methyl amyl alcohol Methyl-n-amyl ketone Methyl bromide 2-Methyl-l -butene... 

Seheuing and Winterhalder treated 2 6-distr3rrylpyridine tetra-bromide with potassium hydroxide in alcohol, so producing 2 6-di-)3-phenylacetylenylpyridine (XI) which by the action of 50 per cent, sulphuric acid was converted into 2 6-diphenacylpyridine (XII), and this, on hydrogenation in presence of platinic oxide, barium sulphate and methyl alcohol, was reduced to 2 6-di-(6-hydroxy-(6-phenylethylpyridine, and the hydrochloride of this, on similar catalytic hydrogenation, yielded worlobelanidine (XIII). This can be methylated to lobelanidine, from which in turn dMobeline and lobelanine can be obtained. 

Reaction.—a too c.c. flask to a short upright condenser (see Fig. 86) and to the upper end of the condensei attach a vertical delivery tube, dipping into an ammoniacal cuprous chloride solution. Pour 2—3 c.c. of ethylene bromide into the flask with 4 times its volume of strong methyl alcoholic potash, which is prepared by boiling methyl alcohol with excess of caustic potash on the water-bath with upright condenser. On gently heating, a rapid evolution of acetylene occurs and the characteristic brown copper compound (C2H,Cu,HjO) is precipitated from the cuprous chloride solution. 

To a solution of 60 g of potassium xanthogenate in 240 cc of water there is added dropwise, while being cooled with ice, a solution of 42 g of 3,4-bis-bromomethyl-4-hydroxy-5-methyl-pyridinium-bromide In 1 liter of water so that the temperature remains between 2°C and 5°C. After stirring for 1 hour at the same temperature, the water is decanted off and the residue is triturated with acetone. Yield 25 g of 4-hydroxymethyl-5-hydroxy-6-methyl-pyridyl-(3)-methy I xanthogenate melting point 170°C to 171°C (alcohol, decomposition). 

In the present instance, the product is a tertiary alcohol with two methyl groups and one props7 group. Starting from a ketone, the possibilities are addition of methyl-magnesium bromide to 2-pentanone and addition of propylmagnesium bromide to acetone. 

A synthetically useful diastereoselectivity (90% dc) was observed with the addition of methyl-magnesium bromide to a-epoxy aldehyde 25 in the presence of titanium(IV) chloride60. After treatment of the crude product with sodium hydride, the yy -epoxy alcohol 26 was obtained in 40% yield. The yyn-product corresponds to a chelation-controlled attack of 25 by the nucleophile. Isolation of compound 28, however, reveals that the addition reaction proceeds via a regioselective ring-opening of the epoxide, which affords the titanium-complexed chloro-hydrin 27. Chelation-controlled attack of 27 by the nucleophile leads to the -syn-diastereomer 28, which is converted to the epoxy alcohol 26 by treatment with sodium hydride. 

Methyl fi-bromopropionate has been prepared by the esterification of /3-bromopropionic acid with methyl alcohol alone1 and through the use of hydrogen bromide as a catalyst,2 and by the direct addition of hydrogen bromide to methyl acrylate.2... 

On the basis of products formed in a number of condensation reactions only confusion results for any step by step mechanism involving specific identifiable species as intermediates. Here are some of the facts. Benzene condenses with cyclopropane to form n-propylbenzene (Simons et al., 44). Normal propyl bromide gives chiefly isopropyl benzene (Simons and Archer, 36) as does propylene (Simons and Archer, 28). Ethyl alcohol gives ethylbenzene, but methyl alcohol does not give... 

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