Potassium thiocyanate → Methyl 2-amino-4-methoxybenzo[d]thiazole-6-carboxylate

Participants

Reaction Steps

To a solution of methyl 4-amino-3-methoxybenzoate (307 g, 1.696 mol) in anhydrous methanol (4 L) was added an intimated mixture of KSCN (1640 g, 16.9 mol) and anhydrous CuSO4 (1350 g, 8.44 mol) in one portion. The mixture was heated to reflux for 4 h. TLC (EtOAc/Petroleum ether 1:4) showed the reaction was complete. The mixture was filtered and the filtrate was diluted with water. The solution was heated to boiling until a slightly clear solution formed. The mixture was cooled to ambient temperature and left standing for 1 day. A dark yellow solid was formed, which was collected by filtration to afford the desired product (338 g, 84%) as a dark yellow solid. 1H NMR (400 MHz, CDCl3): δ 9.000-8.200 (br, 2H), 8.052 (s, 1H), 7.435 (s, 1H), 3.927 (s, 3H), 3.827 (s, 3H).

Provenance & Evidence