Lawesson's reagent → Tert-butyl 10-(5-methylthiazol-2-yl)-8-(2,2,2-trifluoroethyl)-11-oxa-3,8-diazaspiro[5.5]undecane-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

Tert-butyl 10-(acetonylcarbamoyl)-8-(2,2,2-trifluoroethyl)-11-oxa-3,8-diazaspiro[5.5]undecane-3-carboxylate (80 mg, 0.18 mmol) was dissolved in anhydrous THF (1.5 mL) followed by the addition of Lawesson's reagent (114 mg, 0.27 mmol) and the reaction mixture was heated at 70° C. for 1 hour under an atmosphere of nitrogen. The reaction mixture was cooled to room temperature and the solvent was removed under reduced pressure. The residue was purified by silica gel column chromatography using 0-10% EtOAc in DCM as eluent to yield tert-butyl 10-(5-methylthiazol-2-yl)-8-(2,2,2-trifluoroethyl)-11-oxa-3,8-diazaspiro[5.5]undecane-3-carboxylate (95 mg, 100%). ESI-MS m/z calc. 435.5. found 436.5 (M+1)+; Retention time: 1.67 minutes (3 min run); 1H NMR (400 MHz, CDCl3) δ 7.54 (s, 1H), 5.20 (dd, J=9.4, 0.8 Hz, 1H), 3.82-3.76 (m, 2H), 3.43 (d, J=10.1 Hz, 1H), 3.31-3.21 (m, 1H), 3.09-2.94 (m, 3H), 2.72 (dd, J=11.4, 0.5 Hz, 1H), 2.50 (s, 1H), 2.46 (s, 3H), 2.45-2.38 (m, 2H), 1.79-1.67 (m, 1H), 1.65-1.57 (m, 1H), 1.53 (dd, J=11.2, 4.8 Hz, 1H), 1.45 (s, 9H).

Provenance & Evidence