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With hydrogenchloride; potassium hydroxide; In (2S)-N-methyl-1-phenylpropan-2-amine hydrate; dimethyl sulfoxide; |
EXAMPLE 2 STR16 6-Nitro-7-(3-chloro-4-oxo-4H-pyridin-1-yl)-1,4-dihydroquinoxaline-2,3-dione First, 267 mg of 7-fluoro-6-nitro-1,4-dihydroquinoxaline-2,3-dione, 171 mg of <strong>[89284-20-8]3-chloro-4-hydroxypyridine</strong>, and 92 mg of powdered potassium hydroxide were added to 3 ml of dry dimethylsulfoxide. The mixture was allowed to react at 130 C. for 80 minutes in a nitrogen atmosphere. Ice water and 4N hydrochloric acid were then added to the reaction mixture so as to adjust its pH to about 2. The resultant yellow precipitate was filtered and washed with water. The precipitate was recrystallized with a mixture of dimethylformaldehyde and water to give 376 mg of yellowish white 6-nitro-7-(3-chloro-4-oxo-4H-pyridin-1-yl)-1,4-dihydroquinoxaline-2,3-dione. Melting point: >300 C. Elemental analysis (analyzed as C13 H7 N4 O5 Cl.C3 H7 NO.H2 O) Calculated: C,45.13; H,3.79; N,16.45; Cl,8.33 (%) Found: C,45.14; H,3.46; N, 16.33; Cl, 8.57 (%) H1 -NMR (d6 -DMSO)delta: 6.38 (1H, d, J=7.8 Hz), 7.27 (1H, s), 7.86 (1H, dd, J=7.8, 2.4 Hz), 8.02 (1H, s), 8.42 (1H, d, J=2.4 Hz), 12.43 (2H, br. s). |