Diisopropylethylamine → HCID 57896723, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of 1-(4-fluorophenylsulfonyl)-2,3-dihydro-1H-pyrido[2,3-b][1,4]oxazine-7-carbonyl chloride (200 mg, 0.561 mmol) in DCM (5 mL) and water (1 mL) was added ethyl 2-(hydroxyamino)-2-iminoacetate (143.5 mg, 1.086 mmol) and DIPEA (230 μL, 1.317 mmol) to give a pink suspension. The reaction was stirred at 40° C. for 1.5 hours. LCMS analysis of the reaction mixture indicated complete consumption of starting material. The reaction mixture was extracted with DCM (2×10 mL) dried over anhydrous Na2SO4 and concentrated in vacuo. The resulting solid was dissolved in THF (6 mL) and treated with TBAF (0.561 mL, 0.561 mmol). The resulting yellow solution was stirred overnight. LCMS analysis of the reaction indicated consumption of the intermediate. The solvent was removed under reduced pressure. The resulting paste was purified by flash column chromatography using a gradient elution of hexanes with 30-100% EtOAc. Ethyl 5-(1-(4-fluorophenylsulfonyl)-2,3-dihydro-1H-pyrido[2,3-b][1,4]oxazin-7-yl)-1,2,4-oxadiazole-3-carboxylate (120 mg, 0.276 mmol, 49.2%) was isolated as an off-white solid. LCMS (+ESI) m/z=435.0 [M+H]+.

Provenance & Evidence