ESIUM BROMIDE

Thermal iaomerization at 220° in the aljsenee of cataJyat, or iso-merization at W in the preaeuce of tna esium bromide, w gives a nuxture of 2-iDetihyh clfJtexanone and aaetylayolopentane (Eq. -141... 

Cyanopyrazine treated with a Grignard solution of methylmagnesium bromide in ether followed by treatment with dilute hydrochloric acid formed 2-acetyl-pyrazine (138). In a similar manner, 2-acetyl-5(and 6)-methylpyrazine (1327), 5-acetyl-2,3-diphenylpyrazine (866), and 2-acetyl-3,5,6-trimethylpyrazine (866) were prepared. 2-Cyanopyrazine with phenylma esium bromide has been reported to give 2-(C-imino-C-phenylmethyl)pyrazine (1220). 

Draw the initial product when phenylma esium bromide reacts with hexanenitrile and then the final product when that is treated with aqueous acid. 

Much more remarkable is the similar condensation, discovered by Koelsch and Anthes, of phenylim esium bromide with 1-benzonaphthen-1-one (22). The product underwent dehydrogenation to yield 9-phenyl-l-benzonaphthene-1 -one. 

A new process has recently been described for the preparation of organotin compounds (117) by electrolysis of alkyl halide solutions in butyl acrylate (or other ester) with added bromine and stannous bromide. The anode was tin and the cathode nu esium. The authors noticed that the magnesium cathode disintegrated during electrolysis, and the process probably takes place through intermediate formation of an organomagnesium compound. 

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