Cesium carbonate → methyl 3-hydroxy-4-(5-morpholino-7-oxo-7H-thieno[3,2-b]pyran-3-yl)thiophene-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

A 2 mL conical microwave vial was charged with a magnetic stirring bar, 5-morpholino-7-oxo-7H-thieno[3,2-b]pyran-3-ylboronic acid (69) (57 mg, 0.16 mmol), cesium carbonate (102 mg, 0.31 mmol), methyl 4-bromo-3-hydroxythiophene-2-carboxylate (56 mg, 0.24 mmol), tetrakis(triphenylphosphine)palladium(0) (9 mg, 0.08 mmol), and dimethoxyethane (0.5 mL). The reaction mixture was magnetically stirred and heated via microwave irradiation for 15 minutes at 140° C. Upon cooling to room temperature, the reaction was concentrated in vacuo and purified using high-pressure liquid chromatography to give methyl 3-hydroxy-4-(5-morpholino-7-oxo-7H-thieno[3,2-b]pyran-3-yl)thiophene-2-carboxylate (21).

Provenance & Evidence