[Cl:1][C:2]1[CH:3]=[C:4]([NH2:12])[C:5]([NH2:11])=[CH:6][C:7]=1[N+:8]([O-:10])=[O:9].[S:13](Cl)(Cl)=O.C([O-])(O)=O.[Na+]>ClCCl>[Cl:1][C:2]1[C:7]([N+:8]([O-:10])=[O:9])=[CH:6][C:5]2=[N:11][S:13][N:12]=[C:4]2[CH:3]=1A solution obtained by dissolving 4-chloro-5-nitrobenzene-1,2-diamine (1) (15 g, 0.0799 mol) in 500 mL of dichloromethane (DCM) is cooled down to 0° C., and thionyl chloride (SOCl2, 11.7 mL, 0.159 mol, 2.0 eq) is slowly dripped into the solution. The reactant is agitated and reflowed for 16 hours, cooled down to room temperature, and condensed under a reduced pressure. The condensate is dissolved again in dichloromethane, cleaned with a saturated NaHCO3 aqueous solution, and subfractionated. An organic layer is dried, condensed under a reduced pressure, and passed through a silica column so as to obtain thin brown solid-phase compound (2) (15 g, yield: 87%). 1H NMR (400 MHz, CDCl3): δ ppm 8.49 (s, 1H), 8.26 (s, 1H).
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