Synthesis of derivatives of condensed imidazole systems from 2-haloimidazoles and 8-haloxanthines

Properties of haloimidazoles (review)

“…Derivatives of 3H-selenopheno [2,3-d]imidazole 134 [76,77] and 1H-thieno [2,3-d]imidazole 135 [31,78] were synthesized by a similar scheme (yields 73-85%). [48], and imidazo[2,1-b]thiazole derivatives 144 were obtained from them by dehydration (yields 60-80%) [50]. The reactions of 2-bromoimidazoles 56 with ammonia, primary amines, and hydrazines take place with closure of an imidazole or as-triazine ring and the formation of the corresponding derivatives of imidazo[1,2-a]-imidazole 151 [48,49] The 2-aminoimidazoles 153 were obtained from the 2-bromoimidazoles 57 and ammonia or primary amines (yields 49-94%) [81].…”

“…The reactions of 2-bromoimidazoles 56 with ammonia, primary amines, and hydrazines take place with closure of an imidazole or as-triazine ring and the formation of the corresponding derivatives of imidazo[1,2-a]-imidazole 151 [48,49] The 2-aminoimidazoles 153 were obtained from the 2-bromoimidazoles 57 and ammonia or primary amines (yields 49-94%) [81]. Treatment of the products with SOCl 2 or POCl 3 led to the closure of the imidazole ring and the formation of derivatives of 2,3-dihydroimidazo[1,2-a]imidazole 154 (yields 43-56%) [51,52]. The trimerization of 2-fluoroimidazole (146) (R = H), leading to the trimer 158 (yield 92%), is also nucleophilic substitution [80,82].…”

“…The alkylation of 2-haloimidazoles 53a-c with aralkyl bromides leads to the corresponding 1-aralkylsubstituted compounds 54a-c (yields 58-93%) [45][46][47]. The reaction of 2-bromo-4,5-diphenylimidazole (55) with α-bromo ketones and also with β-halo alcohols and oxiranes leads to the ketones 56 [48,50] and alcohols 57 [51,52] 1-Alkyl(aralkyl)-substituted dibromo [29,31], diiodo [20], dichloro [38], tribromo [29,31,38,[54][55][56], triiodo [20], and trichloro [35,56] The synthesis of the glycosides of haloimidazoles is more complicated. The first of them was described in [57].…”