20358-02-5

5391-30-0

20358-02-5

General procedure for the synthesis of 2-amino-4-bromobenzothiazole from o-bromophenylthiourea: (II) LiBr (1.5 eq.) was added to a solution of acetic acid (50 ml) of the product (5 g, 21.64 mmol) obtained in step (I) at room temperature. Subsequently, the reaction mixture was cooled to 0 °C and bromine (1 eq.) was slowly added. After addition, the reaction mixture was warmed to 85 °C and the reaction was continuously stirred for 16 hours. Upon completion of the reaction, the reaction was quenched with sodium thiosulfate solution and the mixture was diluted with ethyl acetate. The organic phase was separated and washed sequentially with water and saturated NaCl solution. The organic phase was dried over anhydrous Na2SO4 and concentrated under reduced pressure to remove the solvent. The crude product was purified by column chromatography (eluent: ethyl acetate/hexane mixed solvent) to afford the target product 2-amino-4-bromobenzothiazole in 68.3% yield.