Synthesis of New Bis‐imidazole Derivatives

The reaction of aldimines with α ‐(hydroxyimino) ketones of type 10 (1,2‐diketone monooximes) was used to prepare 2‐unsubstituted imidazole 3‐oxides 11 bearing an alkanol chain at N(1) ( Scheme 2, Table 1 ). These products were transformed into the corresponding 2 H ‐imidazol‐2‐ones 13 and 2 H ‐imidazole‐2‐thiones 14 by treatment with Ac 2 O and 2,2,4,4‐tetramethylcyclobutane‐1,3‐dithione, respectively ( Scheme 3 ). The three‐component reaction of 10 , formaldehyde, and an alkane‐1, ω ‐diamine 15 gave the bis[1 H ‐imidazole 3‐oxides] 16 ( Scheme 4, Table 2 ). With Ac 2 O, 2,2,4,4‐tetramethylcyclobutane‐1,3‐dithione or Raney ‐Ni, the latter reacted to give the corresponding bis[2 H ‐imidazol‐2‐ones] 19 and 20 , bis[2 H ‐imidazol‐2‐thione] 21 , and bis[imidazole] 22 , respectively ( Schemes 5 and 6 ). The structures of 11a and 16b were established by X‐ray crystallography.