Pyridine → 6-[4-[N-acetyl-4-(acetyloxy)-L-prolylamino]phenyl]-1,2-dihydro-2-oxonicotinic acid

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Reaction Steps

A solution of 29.9 g (0.078 mol) of the above pyridone acid, 120 ml of pyridine, and 60 ml of acetic anhydride is stirred overnight at room temperature. The solution is cooled and upon adding methanol, a precipitate forms. The mixture is cooled and then filtered and the solid is air dried. The solid is recrystallized from 1800 ml of 20% water in methanol and dried at 50° under vacuum to give 21.1 g of 6-[4-[N-acetyl-4-(acetyloxy)-L-prolylamino]phenyl]-1,2-dihydro-2-oxonicotinic acid; [α]D23 +17.3° (cl, 75% DMF/pyridine).

Provenance & Evidence