Novel imidazo[1,2-a]pyrazine derivatives as potent reversible inhibitors of the gastric H+/K+-ATPase

C–H Bond Functionalization Under Metalation–Deprotonation Process: Regioselective Direct Arylation of 3-Aminoimidazo[1,2-a]pyrazine

“…Imidazo­[1,2- a ]­pyrazines and their derivatives with 3-aryl/alkyl-amine, 2-aryl/alkyl and 6-aryl substitutions have been found to possess a wide range of bioactivities. , Analogues of this scaffold represent various marketed drugs such as zolpidem and zolimidine. C6-Aryl derivatives of these compounds are normally prepared by a sequence of reactions. , It uses bromination of 2-aminopyrazine, condensation of 2-amino-5-bromopyrazine with α-haloketone or with aldehyde and isocyanide to produce 6-bromo-imidazopyrazine, and the Suzuki coupling with boronic acid. In addition, bromination of 2-aminopyrazine produces also unwanted regioisomeric brominated and polybromo derivatives .…”

Efficient Halogenation of 2-Aminopyrazine

“…12 More recently, Pastor and co-workers 13 used Br 2 in pyridine-chloroform and obtained only the dibrominated compound in 36% yield (Table 1, entry 7). Using dichloromethane as a solvent and NBS as halogenating agent, Zimmermann and co-workers 14 improved the result (Table 1, entry 8).…”

Recent advances in development of imidazo[1,2-a]pyrazines: synthesis, reactivity and their biological applications

“…The subsequent condensation of 79 with 3-bromo-2-butanone smoothly proceeded to obtain substituted 6-bromoimidazo[1,2-a]pyrazine 80, which was isolated as oxalic acid salt in 70% yield (Scheme 23). 67 Addlagatta and coworkers synthesized 2-substituted imidazo[1,2-a]pyrazine 81 by condensing 2-aminopyrazine/ 2-amino-5-methylpyrazine with halosubstituted carbonyl compounds in ethanol in 50%-55% yields. Out of all the phenacyl bromides, the reaction with 4-fluorophenacyl bromide was very effective and high yielding.…”