Hydrogen Peroxide → HCID 18992661, compound

Participants

Reaction Steps

To a stirred solution of 2.5 g of 2-pyrrolidinone (Aldrich) in 100 mL of chloroform was added 4.5 g of phosphorus oxychloride at room temperature. The mixture was stirred for 2.5 hours at room temperature. To the above mixture was then added dropwise a solution of 5 g of 4,6-dichloroanthranilic acid (prepared from the corresponding isatine: T. Sandmeyer, Helv. Chim. Acta, 2:234 (1919), by oxidation with alkaline hydrogen peroxide, following the procedure described by Baker, et al, J. Org. Chem., 18:141 (1952) for the synthesis of 3-chloroanthranilic acid) in 50 mL of chloroform, containing 10 mL of triethylamine. Then the mixture was heated to reflux for 6 hours. Then the reaction mixture was carefully treated with 10 mL of water (exothermic!), followed by 10 g of solid anhydrous potassium carbonate. The mixture was filtered and the filtrate was concentrated in vacuo. The residue was chromatographed on silica gel using 10:1 chloroform:ethyl acetate as eluent. After concentration in vacuo of the appropriate fractions, there was obtained 1.5 g of crystalline 6,8-dichloro-2,3-dihydropyrrolo[2,1-b]quinazolin-9(1H)-one), which was used as such in the next step.

Provenance & Evidence