Regioselective single-step synthesis of 2-aminoimidazole derivatives

Red-shifted and pH-responsive imidazole-based azo dyes with potent antimicrobial activity

“…Amidrazones have been widely described given their vast applications in chemistry, particularly in the synthesis of heterocycles and azo precursors. [18][19][20][21] It was previously reported that these compounds were readily oxidized when exposed to the air, 22 but similar studies are quite rare in the literature. In a previous work of our research group, imidazole-based amidrazones 1 were synthesized and exhibited potent antimicrobial properties.…”

“…Classical construction of the 2-aminoimidazole moiety by condensation of a-aminoketones with cyanamides, or a-haloketones with guanidine derivatives, suffers from unstable precursors and narrow application scope. 16 More recent approaches involve the reaction between propargylic amines and carbodiimides, 17,18 but major drawbacks include the use of expensive catalysts, harsh conditions and the availability of the reagents. Functionalization of imidazole derivatives is another approach, 18 but it usually requires multiple steps, protection/deprotection strategies, and activation of C-2 position for the introduction of the amine.…”

“…16 More recent approaches involve the reaction between propargylic amines and carbodiimides, 17,18 but major drawbacks include the use of expensive catalysts, harsh conditions and the availability of the reagents. Functionalization of imidazole derivatives is another approach, 18 but it usually requires multiple steps, protection/deprotection strategies, and activation of C-2 position for the introduction of the amine. Herein, a totally novel, versatile and affordable method for the synthesis of a new class of azo dyes containing a 2aminoimidazole moiety is reported.…”

“…Their quite unusual colours change from magenta to blue, which rely on the uncommon substituents pattern in the imidazole scaffold. Amidrazones have been widely described given their vast applications in chemistry, particularly in the synthesis of heterocycles and azo precursors [18][19][20][21] . It was previously reported that these compounds were readily oxidized when exposed to the air 22 , but similar studies are quite rare in the literature.…”

Recent advances in the synthesis of imidazoles

“…For example, Li et al recently reported the synthesis of 2-aminoimidazoles 63 from the reaction of carbodiimides 61 with propargyl amine (62) in moderate to good isolated yield (Scheme 13). 33 The reaction conditions were tolerant of both arylhalides and heteroarylhalides. In addition, the N-1 nitrogen could be substituted by either aryl or benzyl groups depending on the starting material that was employed.…”