[Cl:1][C:2]1[CH:3]=[C:4]([N+:20]([O-:22])=O)[C:5]([NH:12][C:13]([C:15](OCC)=[O:16])=[O:14])=[C:6]([C:8]([F:11])([F:10])[F:9])[CH:7]=1.CN(C)C=O.N.[H][H]>O1CCCC1.[Pt]>[Cl:1][C:2]1[CH:3]=[C:4]2[C:5]([NH:12][C:13](=[O:14])[C:15](=[O:16])[N:20]2[OH:22])=[C:6]([C:8]([F:11])([F:10])[F:9])[CH:7]=1
To a solution of 1.0 g (2.94 mmol) 5-chloro-2-ethoxalylamino-3-nitrobenzotrifluoride in 75 ml tetrahydrofuran was added 25 ml dimethylformamide and 1.0 ml 25% aqueous ammonia. The mixture was hydrogenated at atm. pressure by using 100 mg 5% Pt-C as a catalyst. When the hydrogen uptake was completed, the catalyst was filtered off, and the filtrate was evaporated in vacuo. The residue was stirred with 1N aqueous hydrochloric acid to give 0.66 g (80%) of 7-chloro-1-hydroxy-5-trifluoromethylquinoxaline -2,3(1H,4H)-dione. M.P. 275° C. decomp. 1H-NMR (DMSO-d6): 11.7 (2H, m), 7.60 (1H, d), 7.43 (1H, d).
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