Ethyl-4-bromo imidazole

Substitution of somewhat more complex side chains on the imidazole nitrogen of the purines leads to CNS stimulant drugs that have also been used as vasodilators and antispasmodic agents. Thus, alkylation of theophyline (2) with ethyl bromoacetate followed by saponification of the product gives acephylline (9). Alkylation with l-bromo-2-chloroethane gives the 2-chloroethyl derivative (10). Reaction of that intermediate with amphetamine yields fenethylline (11). ... 

Ethyl substitution at the imidazole 5-position (469) was found to increase potency over the unsubstituted analogue (468), while methyl substitution (470) had a slightly deleterious effect on binding (Table 6.41). Chloro (491), bromo (492), cyano (493) and fluoromethyl (494) substitution at this position were all well tolerated (Table 6.43). Introduction of a chloro-substituted pyridine (475) in place of the more usual / -chlorophenyl group (470) resulted in a slight loss of affinity for the CBi receptor, as did replacement of the p-chloro group of (470) with bromo (471), fluoro (472) and in particular, met-hoxy (473). Trifluoromethyl substitution (474) however, was well tolerated. 

One-pot multi-bond-forming reactions are one of the ways to address the ever growing demand for efficiency in organic synthesis. Rosini and coworkers have developed (tandem) processes for the synthesis of a highly functionalized tricyclic system. The reaction is simply performed by bringing together, at room temperature, a-bromo aldehydes, ethyl nitroacetate, and chlorodimethylvinylsilane in the presence of imidazole as the base (Eq. 8.83).134... 

In 1997 Howarth [180] reported the preparation of ionic liquids 65 and 66. They reported that imidazolium cations can be used as Lewis acid centers in catalytic amount rather than as solvent (Scheme 66). The bromide salts 65a and 66 were prepared by a literature procedure [181] from TMS protected imidazole 64 and ethyl bromide or (5)-l-bromo-2-methylbutane in refluxing toluene in 46 and 21% yield, respectively. Salt 65a was converted into salt 65b with AgCF3COO in 89% yield. 

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