CAS 54571-66-3 appears in our catalog under these names: Methyl 5–oxopyrrolidine–2–carboxylate, Methyl DL-Pyroglutamate, >98.0%(GC), H-DL-Pyr-OMe 97%, Proline, 5-oxo-, methyl ester, 97%, 97%, Methyl DL-pyroglutamate, 99.85%. Offered by: GLPBio, TCI, Ambeed, Chemat, MedChemExpress. Available pack sizes: 100g, 1g, 5g, 10g, 25g, 500g, 1000g, 250g.