Cesium carbonate → HCID 71699715, compound

Participants

Reaction Conditions

Reaction Steps

A 10 mL Schlenk tube was dried under vacuum, filled with nitrogen and consecutively charged with 19.4 mg (0.102 mmol, 0.2 eq) Cul, 332.3 mg (1.020 mmol, 2.0 eq) Cs2CO3, 100.0 mg (0.714 mmol, 1.4 eq) ethyl 1H-pyrazole-3-carboxylate (6), 102.4 mg (73.0 μL, 0.510 mmol, 1.0 eq) p-bromophenetol and 1 mL dry ACN. The light brown suspension was degassed by vaccum/N2 cycles and stirred first at 82° C. for 7 h and than after adding 0.5 mL dry DMF (solubility issue) at 120° C. for further 65 h. The GC-MS analysis showed full conversion. ACN and DMF were removed under high pressure and the brown residue was suspended in 10 mL EtOAc. After filtration of the brown suspension through a pad of silica and flushing with 150 mL EtOAc the colorless filtrate was concentrated under reduced pressure leading to 52.1 mg (39%) crude product as a green-brown oil. Final purification by column chromatography (CH/EtOAc 3:1, size: 15.5×2.0 cm, 20 g silica gel) yielded the pure title compound.

Provenance & Evidence