Dichloromethane → (S)-ethyl 5-(4-(but-3-en-1-yl)-4-methylpiperidin-1-yl)-6-(1-(tert-butoxy)-2-methoxy-2-oxoethyl)-7-methylimidazo[1,2-a]pyridine-2-carboxylate

Participants

Reaction Steps

To a solution of (S)-ethyl 5-(4-(but-3-en-1-yl)-4-methylpiperidin-1-yl)-6-(1-hydroxy-2-methoxy-2-oxoethyl)-7-methylimidazo[1,2-a]pyridine-2-carboxylate (0.50 g, 1.13 mmolo, 1 equiv) in t-BuOAc (18 mL) was added 70% HClO4 (0.48 mL, 5.64 mmol, 5 equiv). A white precipitate formed. DCM (5 mL) was added to aid solubility. After 1 h, the reaction was carefully added to saturated aqueous NaHCO3 and extracted with DCM (×3). The combined DCM extracts were dried (Na2SO4) and concentrated in vacuo. The crude product was purified by flash column chromatography (0-100% EtOAc/hex) to provide the product (0.16 g, 28%) as a white foam. In addition, starting material (0.38 g) was recovered. 1H NMR (400 MHz, CDCl3) [note: major rotamer transcribed, 3:2 mixture of rotamers] δ8.23 (s, 1H), 7.33 (s, 1H), 6.06 (s, 1H), 5.97-5.81 (m, 1H), 5.17-4.97 (m, 2H), 4.53-4.42 (m, 2H), 3.71 (s, 3H), 3.69-3.64 (m, 1H), 3.57-3.50 (m, 1H), 3.17-3.07 (m, 1H), 2.88 (d, J=12.0 Hz, 1H), 2.46-2.44 (m, 3H), 2.18-2.08 (m, 2H), 1.71-1.58 (m, 6H), 1.48-1.43 (m, 3H), 1.25 (s, 9H), 1.16 (s, 3H); LCMS (ESI, M+1): 500.35.

Provenance & Evidence