Reaction Steps
Ethyl-2-((2-(hex-5-en-1-yloxy)-2-oxoethyl)amino)-2-oxoacetate (0.35 g) and DCM (4 mL) were added to a vessel with stirring followed by the addition of pyridine (0.13 g). Tf2O (0.58 g) was then added to the mixture slowly at ambient temperature. The mixture was stirred at ambient temperature for 4 days after which time the mixture was extracted with 6N HCl (3×10 mL). The combined acid layers were washed with DCM (10 mL) and the pH was adjusted to ˜10 with solid K2CO3. The basic aqueous layer was extracted with DCM (20 mL). The organic layer was concentrated under reduced pressure to provide the title compound (A) and ethyl 2,3,4,5-tetrahydrooxepino[2,3-c]pyridine-7-carboxylate (B) as a 3:1 mixture as based on NMR analysis. 1H NMR (300 MHz, CDCl3) δ ppm 8.38 (s, 0.3H, cmpd B), 8.11 (s, 1H, cmpd A), 7.95 (s, 0.3H, cmpd B), 4.36-4.51 (m, 2.6H, cmpd A/B CH3CH2), 4.17-4.25 (m, 2H, cmpd A OCH2), 4.06-4.13 (m, 0.6H, cmpd B OCH2), 2.85-2.93 (m, 0.6H, cmpd B CH2), 2.71 (t, J=6.53 Hz, 2H, cmpd A CH2), 2.45 (s, 3H, cmpd A CH3), 1.99-2.15 (m, 2.6H, cmpd A/B CH2), 1.54-1.88 (m, 0.6H, cmpd B CH2), 1.44 (t, J=7.12 Hz, 0.9H, cmpd B CH3), 1.44 (t, J=7.12 Hz, 3H, cmpd A CH3); 13C NMR (75 MHz, CDCl3) δ ppm 166.53, 165.01, 162.88, 159.21, 153.21, 143.48, 143.11, 142.72, 139.52, 136.74, 134.94, 130.12, 127.21, 73.82, 65.85, 61.61, 61.21, 33.74, 31.53, 24.97, 22.11, 21.48, 14.56, 14.28; Cmpd A: HRMS (M+Na) m/z, calcd for C12H15NO3Na, 244.0950; found 244.0961; Cmpd B: HRMS (M+H) m/z, calcd for C12H16NO3, 222.1130; found 222.1130.
