[OH:1][C:2]1[C:11]([C:12]([OH:14])=[O:13])=[CH:10][C:9]2[C:4](=[CH:5][CH:6]=[C:7]([C:15]([OH:17])=[O:16])[CH:8]=2)[CH:3]=1.[Br:18]Br.O>C(Cl)(Cl)Cl.CS(C)=O>[Br:18][C:3]1[C:4]2[C:9](=[CH:8][C:7]([C:15]([OH:17])=[O:16])=[CH:6][CH:5]=2)[CH:10]=[C:11]([C:12]([OH:14])=[O:13])[C:2]=1[OH:1]2-Hydroxy-3,6-di-hydroxycarbonylnaphthalene (11.8 g) was dissolved in chloroform (300 g) and dimethyl sulfoxide (100 g), followed by ice-cooling. Then, a solution of bromine (8.0 g) and chloroform (50 g) was added dropwise at not more than 5° C. over 2 hours. After continuously stirring for 1 hour, this solution was poured into water (1500 g) dropwise. The deposit was filtered and then washed with water and dispersed in a small amount of methanol. The dispersion was concentrated under reduced pressure at room temperature and then dried under vacuum to obtain 15.1 g of 1-bromo-2-hydroxy-3,6-di-hydroxycarbonylnaphthalene as a whitish brown crystal (DSC analysis value: 145.2° C.).
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