Cesium carbonate → 8-Methoxy-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 5-bromo-8-methoxy-[1,2,4]triazolo[4,3-a]pyrazine (0.25 g, 1.1 mmol), thiophen-2-ylboronic acid (280 mg, 2.2 mmol), Pd(PPh3)4 (190 mg, 0.16 mmol), Cs2CO3 (530 mg, 1.6 mmol), 1,4-dioxane (11 mL) and water (4 mL). The resulting mixture was heated under N2 at 100° C. overnight. Work-up: the reaction mixture was filtered. The filter cake was washed with EtOAc (10 mL) and the filtrate was extracted with more EtOAc (10 mL×3). The combined organic solutions were washed with brine, dried over anhydrous Na2SO4, and concentrated in vacuo. The residue was purified by flash column chromatography on silica gel with a 1:50 methanol/dichloromethane, to afford 0.25 g (99%) of the product as a yellow solid. MS m/z: 233 (M+H+).

Provenance & Evidence