[NH:1]1[CH2:5][CH2:4][CH2:3][C:2]1=O.P(Cl)(Cl)(Cl)=O.[Cl:12][C:13]1[CH:14]=[C:15]([NH2:23])[C:16](=[C:20]([Cl:22])[CH:21]=1)[C:17](O)=[O:18].N1C2C(=CC=CC=2)C(=O)C1=O.OO.ClC1C=CC=C(C(O)=O)C=1N.C(=O)([O-])[O-].[K+].[K+]>C(Cl)(Cl)Cl.O.C(N(CC)CC)C>[Cl:12][C:13]1[CH:21]=[C:20]([Cl:22])[C:16]2[C:17](=[O:18])[N:1]3[CH2:5][CH2:4][CH2:3][C:2]3=[N:23][C:15]=2[CH:14]=1
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.
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