反应详情

Into a 100 mL two-necked flask are added 6-amino-1,3-benzothiazole-2-thiol (1.92 g, 10.5 mmol) and THF (20 mL), followed by acetaldehyde (0.591 mL, 10.5 mmol), glacial acetic acid (1 mL) and water (1 mL) at 0° C. The suspension is stirred for 1.5 hrs before a solution of NaCNBH3 (0.723 g, 10.5 mmol) in THF (20 mL) is introduced slowly through a dropping funnel. The reaction mixture is stirred at room temperature for 2 hrs after the addition. The precipitates are collected by filtration, washed with water and ether, and dried under reduced pressure to give the intermediate of 6-ethylamino-benzothiazole-2-thiol as light yellow solid (1.8 g, 82%). 1H NMR (CD3OD) δ 1.21 (t, 3H), 3.08 (q, 2H), 6.68-6.72 (m, 2H), 7.04 (d, 2H); ESIMS: m/z 211.0(M+H).

1. additionis introduced slowly through a dropping funnel
2. additionafter the addition
3. filtrationThe precipitates are collected by filtration
4. washwashed with water and ether
5. customdried under reduced pressure