Br[C:2]1[CH:10]=[C:6]([C:7](O)=[O:8])[C:5]([OH:11])=[C:4]([N+]([O-])=O)[CH:3]=1.S(Cl)(Cl)=O.[CH3:19][NH:20][CH3:21].C1COCC1.S(=O)(=O)(O)O>O.C(#N)C>[OH:11][C:5]1[CH:4]=[CH:3][CH:2]=[CH:10][C:6]=1[C:7]([N:20]([CH3:21])[CH3:19])=[O:8]To a three neck flask was charged (50.0 g, 190.8 mmol) of 5-bromo-3-nitro-salicylic acid (Davos, 464 Hudson Terrace, Englewood, N.J. 07362), 200 ml of acetonitrile and 14 ml (191.9 mmol) of thionyl chloride. The resulting mixture was heated at 70° C. for 2 hours. The mixture was then cooled to 5-10° C. and a solution of dimethylamine in THF (2M, 210 ml, 2.2 eq.) was added slowly over one hour. The reaction mixture was then warmed to ambient temperature and stirred for another 3 hours. The mixture was mixed with 100 ml of water and acidified with sulfuric acid (2N, 45 ml) to a pH of 2. Additional 800 ml of water was added slowly over one hour while solids product precipitated out from the mixture. The suspension was cooled to 5° C. The solids were filtered and washed with water (200 ml). The wet crude product was recrystallized from 400 ml of hot ethanol to give 44.2 g (80%) of the compound of formula IV(a). Melting point: 181° C.-183° C. 1H NMR (400 MHz, DMSO): δ (ppm) 10.94 (s, 1H), 8.16 (d, 1H, J=2.5 Hz), 7.76 (d, 1H, J=2.5 Hz), 2.9 (br, 6H). 13C NMR (100.62 MHz, DMSO): 164.7, 147.5, 137.6, 135.9, 131.5, 127.4, 110.0, 37.6, 34.3. Anal. calcd. for C9H9BrN2O4 (289.08): C, 37.39; H, 3.14; N, 9.69. Found: C, 37.42; H, 2.90; N, 9.55.
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