Water → 6-Amino-7-bromobenzothiazole
Reaction equation
[S:1]1[C:5]2[CH:6]=[C:7]([NH2:10])[CH:8]=[CH:9][C:4]=2[N:3]=[CH:2]1.[Br:11]Br.O>C(O)(=O)C>[Br:11][C:6]1[C:5]2[S:1][CH:2]=[N:3][C:4]=2[CH:9]=[CH:8][C:7]=1[NH2:10]Participants
5
Reactant 3
Product 1
Reagents, catalysts & solvents 1
Procedure
To a solution of benzothiazol-6-ylamine (6.4 g, 42.6 mmol) in glacial acetic acid (40 mL) was added bromine (2.18 mL) in glacial acetic acid (10 mL) dropwise. The reaction mixture was stirred at RT for 1 h. Water (160 mL) was added to the reaction mixture and the solid formed was extracted with ethyl acetate (3×40 mL). The combined organic fractions were washed with saturated aqueous sodium bicarbonate solution (200 mL), water (100 mL), and brine (20 mL), dried over anhydrous sodium sulfate, and concentrated. Purification of the residue by column chromatography (20% ethyl acetate:hexanes) afforded 6.5 g (67%) of the title compound as a yellow solid. 1H NMR (300 MHz, CDCl3): δ 4.31 (br. s, 2H), 7.02 (d, J=8.4 Hz, 1H), 7.92 (d, J=8.4 Hz, 1H), 8.80 (s, 1H).