Acetic Anhydride → ethyl 1-[(cis)-1-acetyl-2-methyl-4-({[(1-methylethyl)oxy]carbonyl}amino)-1,2,3,4-tetrahydro-6-quinolinyl]-1H-imidazole-4-carboxylate

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Reaction Steps

Acetic anhydride (20 mL) was added to ethyl 1-[(cis)-2-methyl-4-({[(1-methylethyl)oxy]carbonyl}amino)-1,2,3,4-tetrahydro-6-quinolinyl]-1H-imidazole-4-carboxylate (for a preparation see intermediate 83) (3.5 g, 9.06 mmol). The resulting mixture was stirred at room temperature for 24 h then most of the solvent was removed in vacuo. The residue was dissolved in AcOEt (30 mL) and washed repeatedly with a saturated NaHCO3 aqueous solution until the later was basic. The organic phase was then washed with water and brine, dried over MgSO4 and concentrated in vacuo. Purification of the residue by flash chromatography on silica gel (gradient: 0 to 5% MeOH in DCM) gave ethyl 1-[(cis)-1-acetyl-2-methyl-4-({[(1-methylethyl)oxy]carbonyl}amino)-1,2,3,4-tetrahydro-6-quinolinyl]-1H-imidazole-4-carboxylate (3.8 g, 8.87 mmol, 98%) as a colourless foam. LCMS (method G): Retention time 0.83 min, [M+H]+=429.11

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