Phosphorus oxychloride → 8-Chloro-5-(thiophen-2-yl)-[1,2,4]triazolo[4,3-a]pyrazine

Participants

Reaction Conditions

Reaction Steps

A 50 mL round bottom flask was charged with 8-methoxy-5-(thiophen-2-yl)-[1,2,4]triazolo[4,3-a]pyrazine (0.30 g, 1.3 mmol) and POCl3 (3 mL). The mixture was heated at 130° C. overnight. TLC indicated a complete conversion. Work-up: the reaction mixture was concentrated in vacuo. The residue was carefully poured into ice and extracted with EtOAc (10 mL). The organic layer was washed with saturated aqueous NaHCO3 and brine, dried over anhydrous Na2SO4, and concentrated in vacuo. The residue was further purified by flash column chromatography on silica gel with a 1:5 EtOAc/petroleum ether, to afford 0.23 g (75%) of the product as a white solid. MS m/z: 237 (M+H+).

Provenance & Evidence