Triethylamine → Tert-butyl 10-(acetonylcarbamoyl)-8-(2,2,2-trifluoroethyl)-11-oxa-3,8-diazaspiro[5.5]undecane-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

T3P (591 mg, 553 μL of 50% w/w, 0.93 mmol) was added to a mixture of 9-(tert-butoxycarbonyl)-4-(2,2,2-trifluoroethyl)-1-oxa-4,9-diazaspiro[5.5]undecane-2-carboxylic acid (142 mg, 0.37 mmol), 1-aminopropan-2-one hydrochloride salt (41 mg, 0.37 mmol) and Et3N (188 mg, 259 μL, 1.86 mmol) in 2-methyltetrahydrofuran (706 μL). The reaction mixture was then heated at 45° C. for 2 hours. The reaction mixture was cooled to room temperature and partitioned between EtOAc/saturated aq. NaHCO3. The layers were separated and the aqueous layer was extracted with EtOAc (2×). The combined organics were dried over Na2SO4, filtered and concentrated in vacuo to a dark foam. The crude product was purified by silica gel column chromatography using 0-50% EtOAC in DCM as eluent to afford tert-butyl 10-(acetonylcarbamoyl)-8-(2,2,2-trifluoroethyl)-11-oxa-3,8-diazaspiro[5.5]undecane-3-carboxylate (80 mg, 49%) as a yellow solid. ESI-MS m/z calc. 437.5. Found 438.7 (M+1)+; Retention time: 1.01 minutes (3 min run).

Provenance & Evidence