5-amino-2-chlorobenzenethiol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of anhydrous stannous chloride (152.5 g) in conc. hydrochloric acid (150 ml) was cooled to 0° C., and 2-chloro-5-nitrobenzenesulfonyl chloride (34.3 g) was added thereto while stirring. The resultant mixture was heated at 100° C. for 15 minutes while stirring, followed by being allowed to stand. Conc. hydrochloric acid (230 ml) was added to the reaction mixture. The precipitated crystals were collected by filtration, neutralized with a 4% aqueous sodium carbonate solution and extracted with ethyl acetate. The organic layer was dried and concentrated to give 25.0 g of 2-chloro-5-aminothiophenol. M.P., 68.3° C. while stirring The precipitated crystals were collected by filtration extracted with ethyl acetate The organic layer was dried concentrated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of anhydrous stannous chloride (152.5 g) in conc. hydrochloric acid (150 ml) was cooled to 0° C., and 2-chloro-5-nitrobenzenesulfonyl chloride (34.3 g) was added thereto while stirring. The resultant mixture was heated at 100° C. for 15 minutes while stirring, followed by being allowed to stand. Conc. hydrochloric acid (230 ml) was added to the reaction mixture. The precipitated crystals were collected by filtration, neutralized with a 4% aqueous sodium carbonate solution and extracted with ethyl acetate. The organic layer was dried and concentrated to give 25.0 g of 2-chloro-5-aminothiophenol. while stirring The precipitated crystals were collected by filtration extracted with ethyl acetate The organic layer was dried concentrated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: For production of the compound (III), 2-chloro-5-nitrobenzenesulfonyl chloride, i.e. the compound (V), is first reacted with stannous chloride and hydrochloric acid or with zinc and hydrochloric acid or sulfuric acid at a temperature of 40° to 100° C. to give 2-chloro-5-aminothiophenol, i.e. the compound (IV). The amount of the stannous chloride or zinc is usually from 6 to 10 equivalents to the compound (V).