Acetyl chloride → 3-Aminoimidazo(1,2-a)pyridine

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Reaction Steps

To a suspension of amino-pyridine derivative Gen-1 (1 eq.) in toluene are added the aldehyde RzCHO (1 eq.) and benzotriazole (1 eq.). The mixture is stirred at r.t. overnight. Additional aldehyde reagent (0.06 eq.) and benzotriazole (0.06 eq.) are added. After 4 h stirring, potassium cyanide (1.2 eq.) is added, followed by EtOH. The reaction mixture is stirred at r.t. for 5 days. The crude product mixture is then quenched with a 3 M NaOH solution. Solvents are evaporated carefully in vacuo. The residue is diluted with water and EtOAc. The aqueous layer is extracted with EtOAc. The combined organic layers are washed with water and brine, dried over Na2SO4 and concentrated in vacuo. The crude product mixture is dissolved in EtOH and carefully added to a solution of acetyl chloride (2.1 eq.) in EtOH at 0° C. The resulting reaction mixture is stirred at r.t. overnight and then concentrated to dryness to afford the corresponding imidazo[1,2-a]pyridin-3-ylamine as hydrochloride salt.

Provenance & Evidence