20511-15-3

140-89-6

65128-66-7

Synthesis of thiazolo[4,5-c]pyridine-2-thiol (68): 3-amino-4-chloropyridine (67, 1.0 g, 8.3 mmol) was dissolved in 15 mL of anhydrous N,N-dimethylformamide (DMF) under nitrogen protection. Potassium ethylxanthate (KSCSOEt, 2.0 g, 12.5 mmol) was added to this solution in batches. The reaction mixture was stirred at 95-100°C for 15 h. The progress of the reaction was monitored by thin layer chromatography (TLC, unfolding agent: 70% ethyl acetate/hexane) to confirm complete consumption of the raw material. Upon completion of the reaction, the reaction was quenched with 35 mL of ice water followed by the addition of 40 mL of 1 M hydrochloric acid (HCl). The mixture was continued to be stirred for 30 minutes, during which time a precipitate was generated. The precipitate was collected by filtration, washed with 250 mL of water and dried under vacuum over phosphorus pentoxide (P4O10) to afford the target product thiazolo[4,5-c]pyridine-2-thiol (68, 0.98 g, 70% yield).