Hydrochloric Acid → 4-Methyl-5-oxo-L-proline

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Reaction Steps

The crystals (2.0 g) of 2-ethoxycarbonyl-4-methyl-5-oxopyrrolidine in the above-mentioned stage B were dissolved in a 2N sodium hydroxide solution (6 ml), and the solution was stirred at room temperature overnight. The mixture was neutralized with dilute hydrochloric acid, followed by concentration under reduced pressure. The residue was crystallized from water to give 4-methylpyroglutamic acid isomer A (900 mg) as crystals.

Provenance & Evidence