2,5-Dimethoxy-4-chloronitrobenzene reacted with sodium sulfide or sodium disulfide in 95% ethanol, to expect forming 2,5-dimethoxy-4-chloroaniline. However, the data of 1H NMR, 13C NMR, MS techniques and elemental analyses of the reaction products indicated that no reduction of nitro group in 2,5-dimethoxy-4-chloronitrobenzene happened, instead, a chlorine atom in 2,5-dimethoxy-4-chloronitro- benzene was replaced by sulfur anion or bis-sulfur anion, affording 4,4’-dinitro-2,2’,5,5’-tetramethoxydi- phenyl-sulfur or 4,4’-dinitro-2,2’,5,5’-tetramethoxy-diphenyl-bis-sulfur, respectively. Based on this fact, a mechanism of the nucleophilic substitution reaction is proposed.

Key words: sodium sulfide, reduction for nitro group, nucleophilic substitution, 2,5-dimethoxy-4-chloronitrobenzene