Bromo-,5-dimethylimidazole

Whereas the radical anion formed from l-methyl-2(thiomethyl)imidazole has a 7r SOMO, 4-bromo- and 4-iodo-2-methylimidazole, 5-bromo- and 5-iodo-l,2-dimethylimi-dazole and 4,5-dibromo- and 4,5-di-iodo-l,2-dimethylimidazole form cr radical anions in irradiated methanol or MeTHF solutions at 77 K251. 

Bromo- and 5-iodo-l,2-dimethylimidazole did not react under irradiation with PhS ions in liquid ammonia or DMF280. 

The imidazol-5-yl radical 437, on the other hand, has been generated from 5-bromo-l,2-dimethylimidazole 436 using Bu3SnH and an azo-initiator such as AIBN or l,l -azobis(cyclohexanecarbonitrile) (ACN). The addition of the... 

Dimethylimidazole, however, gives the 5-hydroxymethyl derivative, and though it is usually difficult to induce substrates with electron-withdrawing groups to react, l-methyl-5-nitroimidazole forms the 2-hydroxymethyl product (see CHEC-I). Whilst the reaction mechanism is uncertain, it could involve A(-hydroxymethylation followed by rearrangement. Examples include 2-hydroxy-methylation of l,4-dimethyl-5-nitroimidazole in DMSO <87JMC150>, and 5-substitution of 4-bromo-... 

Reactions of Imidazoles. Thermolysis of 1-triphenylmethylimidazole results in migration of the imidazolyl group to yield compound (286). Sensitized photo-oxygenation of 4,5-diphenylimidazole in methanol affords a mixture of the imidazolinone (287) and the imidazolidinone (288). The imidazole (289 R = H) undergoes lithiation at C-5 subsequent treatment with diphenyl disulphide gives the di(phenylthio)-derivative (289 R = PhS). Copyrolysis of 2,4-dimethylimidazole and chloroform results in a complex mixture, containing imidazole and methyl-, dimethyl-, and chloromethyl-pyrimidines and -pyrazines. The confusion about the structures of N-methyl derivatives of iodo-nitro-imidazoles has been cleared up the supposed 1-methyl-2,5-di-iodoimidazole is actually the 4,5-di-iodo-compound it yields 4-iodo-l-methyl-5-nitroimidazole on nitration. The reaction of the bromo-... 

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