Hydrogen Peroxide → Ethyl 1,2,3,4-tetrahydropyrido[1,2-a]benzimidazole-7-carboxylate

Participants

Reaction Steps

Ethyl 3-amino-4-piperidin-1-ylbenzoate (5.38 g, 21.7 mmol) prepared in the Step 3-1-2 was dissolved in formic acid (90%, 40 ml). Hydrogen peroxide solution (20 ml) was added to the solution, and the mixture was heated under reflux for 40 minutes. After being allowed to cool, the mixture was neutralized with a saturated sodium bicarbonate solution and a 25% ammonia water and subjected to extraction with ethyl acetate. The extract was dried over anhydrous magnesium sulfate and then concentrated. The residue was purified by silica gel column chromatography (n-hexane:ethyl acetate=1:1) to give the title compound (3.94 g, 74%) as a light-brown powder.

Provenance & Evidence