反应详情

温度

20 °C

To a solution of 2-amino-6-bromopyridine (1) (253.8 g, 1.467 mol) in DCM (2.5 L) cooled to 5° C. is added ethoxycarbonyl isothiocyanate (173.0 mL, 1.467 mol) dropwise over 15 min. The reaction mixture is then allowed to warm to room temp. (20° C.) and stirred for 16 h. Evaporation in vacuo gives a solid which may be collected by filtration, thoroughly washed with petrol (3×600 mL) and air-dried to afford (2). The thiourea may be used as such for the next step without any purification. 1H (400 MHz, CDCl3) δ 12.03 (1H, br s, NH), 8.81 (1H, d, J 7.8 Hz, H-3), 8.15 (1H, br s, NH), 7.60 (1H, t, J 8.0 Hz, H-4), 7.32 (1H, dd, J 7.7 and 0.6 Hz, H-5), 4.31 (2H, q, J 7.1 Hz, CH2), 1.35 (3H, t, J 7.1 Hz, CH3).

1. customEvaporation in vacuo
2. customgives a solid which
3. filtrationmay be collected by filtration
4. washthoroughly washed with petrol (3×600 mL)
5. customair-dried