4-Methyl-1,3-isobenzofurandione → 3-(4-Methyl-1,3-dioxoisoindolin-2-yl)-2,6-dioxo-5-acetoxypiperidine

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Reaction Steps

A mixture of 2,6-dioxo-3-benzyloxycarbonylamino-5-acetoxypiperidine (9 g, 28.2 mmol) (U. Teubert et al, Arch. Pharm. Pharm. Med. Chem. (1998) 7–12) and Pd/C (10%, 0.9 g) in acetic acid (90 mL) is shaken under hydrogen (50–60 psi) for 3 hours. The suspension is filtered through a pad of Celite and washed with acetic acid. To the filtrate is added 3-methylphthalic anhydride (4.56 g, 28.2 mmol) and this mixture is heated at reflux for 18 hours. The solvent is removed in vacuo to give 3-(4-methyl-1,3-dioxoisoindolin-2-yl)-2,6-dioxo-5-acetoxypiperidine which can be further purified by column chromatography.

Provenance & Evidence