Cesium carbonate → HCID 178436885, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of 5-ethyl-2H-pyrazol-3-ol (4.40 g, 39.2 mmol) in DMF (40 ml) is added cesium carbonate (13.42 g, 41.2 mmol) and the reaction mixture is heated to 50° C. After 5 minutes, 2-bromo-1-(2,4-dichloro-phenyl)-propan-1-one (Intermediate AA) (11.62 g, 41.2 mmol) in DMF (60 ml) is added slowly (addition time 10 minutes, initially yellow) and the reaction is stirred for a further 45 minutes giving a tan solution which is allowed to cool to RT. The reaction mixture is partitioned between EtOAc (150 ml) and 1N Na2CO3 (400 ml) and extracted with EtOAc (4×75 ml). The combined organic extracts are washed with H2O (1×200 ml) and brine (250 ml), dried (Na2SO4), filtered and concentrated in vacuo to yield a brown oil. The residue is pre-absorbed (dissolved in dichloromethane) onto silica gel and purified via Flashmaster (SiO2 340 g Snap cartridge column) eluting with 4:1 iso-hexane/EtOAc to 2:1 iso-hexane/EtOAc to yield the title compound as a pale yellow solid MS: m/z 313.12 [M+H]+

Provenance & Evidence