HCID 88924281, compound → HCID 86672459, compound

Participants

Reaction Conditions

Reaction Steps

To tert-butyl 4-(2,2-difluoroethyl)-2-((2-oxobutyl)carbamoyl)-1-oxa-4,9-diazaspiro[5.5]undecane-9-carboxylate (200 mg, 0.46 mmol) in THF (2 mL) was added Burgess' salt (275 mg, 1.15 mmol) and the reaction mixture was heated at 75° C. under a nitrogen atmosphere for 2 hours. The reaction mixture was cooled to room temperature, and partitioned between EtOAc and saturated aq. NaHCO3. The layers were separated and the aqueous layer was extracted once more with EtOAc. The combined organics were dried over Na2SO4, filtered and concentrated in vacuo to give an orange oil. The residue was purified by silica gel column chromatography using 0-20% EtOAc in DCM as eluent to yield tert-butyl 4-(2,2-difluoroethyl)-2-(5-ethyloxazol-2-yl)-1-oxa-4,9-diazaspiro[5.5]undecane-9-carboxylate (160 mg, 84%) as a colorless oil. ESI-MS m/z calc. 415.2. found 416.5 (M+1)+; Retention time: 2.06 minutes (3 min run); 1H NMR (400 MHz, CDCl3) δ 6.69 (s, 1H), 6.06-5.68 (m, 1H), 4.89 (dd, J=10.7, 2.5 Hz, 1H), 3.85-3.58 (m, 2H), 3.37-3.01 (m, 3H), 2.87-2.59 (m, 6H), 2.45 (d, J=13.6 Hz, 1H), 2.30 (d, J=11.3 Hz, 1H), 1.65-1.48 (m, 3H), 1.45 (s, 9H), 1.25 (t, J=7.6 Hz, 3H).

Provenance & Evidence