Ammonia → 2-Amino-5,7-dibromobenzothiazole

Participants

Reaction Conditions

Reaction Steps

To a solution of (3,5-dibromo-phenyl)-thiourea (35 g, 0.11 mol) in CHCl3 (600 mL) at −55-60° C. was added dropwise a solution of Br2 (40.40 g, 0.25 mol, in 100 ml of CHCl3) over a period of 1 h. The reaction mixture was stirred at −55-60° C. for 15 min followed by refluxing at 70-75° C. for 3 h. The reaction mixture was cooled to room temperature and filtered to get the crude residue that was washed with hexane and diethyl ether. The solid thus obtained was dissolved in H2O, basified with aqueous ammonia solution to pH 10-12 and stirred for 30 min. The solid thus obtained was filtered and washed with water to get the desired product (34.0 g, 98%).

Provenance & Evidence