Selenium Dioxide → (+/-)-3'-Methyl-2',5'-dioxo-6,8-dihydrospiro[cyclopenta[g]quinoline-7,4'-imidazolidine]-2-carboxylic acid

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Reaction Steps

A mixture of (±)-2,3′-dimethyl-6,8-dihydro-2′H,5′H-spiro[cyclopenta[g]quinoline-7,4′-imidazolidine]-2′,5′-dione (500 mg, 1.78 mmol, described in Intermediate 19) and selenium dioxide (592 mg, 5.33 mmol) in dioxane (30 mL) and H2O (3 mL) are heated at reflux for 18 h. The reaction mixture is allowed to cool, filtered through a pad of Celite, and the filtrate is concentrated in vacuo to give the title compound. MS: m/z=312 (M+1).

Provenance & Evidence