Water → 3-(3-Bromobenzyl)-2-oxo-1-oxa-3,8-diazaspiro[4.5]decane-8-carboxylic acid (2,5-difluorophenyl)amide

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Reaction Steps

The compound A6 (0.50 g, 1.18 mmol) was dissolved in DCM (3 mL) and combined with trifluoroacetic acid (3 mL). The reaction mixture was stirred for 5 min at RT and the solvent was then removed under a vacuum. The residue was combined repeatedly with toluene and the solvent was then removed again. The residue was then combined with sat. aq. NaHCO3 solution and repeatedly extracted with EtOAc. The combined organic phases were dried over Na2SO4 and the solvent was removed under a vacuum. The residue was redissolved in anhydrous THF (5 mL) and combined with a little triethylamine. The reaction mixture was combined with 2,5-difluorophenyl isocyanate (145 μL, 1.23 mmol), stirred for 18 h at RT and combined with water and EtOAc. The organic phase was separated off and the aqueous phase repeatedly extracted with EtOAc. The combined organic phases were washed with sat. aq. NaCl solution, dried over Na2SO4 and the solvent was removed under a vacuum. The residue was purified by column chromatography (SiO2, heptane/EtOAc 2:1). After crystallisation from heptane and DCM, 483 mg (85% of theoretical) of the desired product 3-(3-bromobenzyl)-2-oxo-1-oxa-3,8-diazaspiro[4.5]decane-8-carboxylic acid (2,5-difluorophenyl)amide (29) were obtained.

Provenance & Evidence