Dimethylformamide → 5-Fluoro-3-[2-(5-methyl-3-oxo-2-phenyl-2,3-dihydro-pyridazin-4-yl)-butyrylamino]-4-oxo-pentanoic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

A mixture of the carboxylic acid derivative of Preparation 1-5) (271 mg, 1.00 mmol), 3-amino-5-fluoro-4-hydroxy-pentanoic acid tert-butyl ester (see Tetrahedron Letters, 1994, 35(52), 9693-9696, 248 mg, 1.2 eq) and HATU (494 mg, 1.3 eq) was cooled to 0° C., triethylamine (0.56 mL, 4.0 eq) was added thereto in DMF solvent (5 mL), and the mixture was reacted for one day. The solvent was distilled under reduced pressure. The residue was extracted with ethyl acetate (30 mL×2), washed with water, aqueous sodium hydrogen carbonate solution and aqueous sodium chloride solution, dried (anhydrous Na2SO4), and concentrated under reduced pressure. To this compound and Dess-Martin reagent (848 mg, 2.0 eq) was added anhydrous dichloromethane (4 mL), which was then stirred for 1 h at room temperature. The reaction was stopped by isopropyl alcohol (1 mL). The solid was removed by celite filtration under reduced pressure, and extracted with ethyl acetate (20 mL×2). The extract was washed with water, saturated aqueous sodium hydrogen carbonate solution and aqueous sodium chloride solution, dried (anhydrous Na2SO4), and concentrated under reduced pressure. The residue was separated by column chromatography (30-40% ethyl acetate-hexane) to give 330 mg (72%) of the title compound.

Provenance & Evidence