Potassium Carbonate → HCID 56597422, compound

Participants

Reaction Steps

Ethyl-4-bromobutyrate (45 μL, 0.30 mmol, 1.50 eq.) was added to a solution of (±)-1-(5-fluoro-2-hydroxy-phenyl)-3,4-dihydro-1H-isoquinoline-2-carboxylic acid benzyl ester (75 mg, 0.20 mmol, 1.00 eq.) and K2CO3 (83 mg, 0.60 mmol) in DMF (0.7 mL). The mixture was stirred at r.t. for 2 hours. Ethyl-4-bromobutyrate (22 μL, 0.15 mmol, 0.75 eq.) was added again and the mixture was stirred at r.t. for 18 hours. The reaction mixture was diluted with AcOEt and water. The layers were separated and the aq. phase was extracted with AcOEt (2×). The combined org. phases were washed with water and sat. aq. NaCl soln., dried over MgSO4, filtered and concentrated in vacuo. To a solution of the crude ester in THF (0.9 mL), 1M aq. NaOH soln. (0.50 mL) was added. The resulting solution was stirred at r.t. during 62 hours. The org. solvent was removed in vacuo. The residue was diluted with water and 1M aq. HCl soln. (0.8 mL) followed by DCM. The mixture was shaked then the layers were separated and the aq. phase was extracted with DCM (2×). The comb. org. phases were dried over MgSO4, filtered and concentrated in vacuo. The crude mixture, redissolved in DMF (1.2 mL), was purified by prep. HPLC (column: Atlantis, 19×50 mm, 5 um, UV/MS, acidic conditions) and evaporated (genevac) to give the desired acid.

Provenance & Evidence