反应详情

温度

100 °C

A suspension of polyphosphoric acid (115%, 109 g) and powdered 3-(5-(methoxycarbonyl)-1H-pyrrol-2-yl)propanoic acid (12.1 g, 51.8 mmol) in 1,2-dichloroethane (40 mL) was heated for 1 h at 100° C. with occasional mixing with a large spatula. Water (100 mL) was added and the mixture was carefully poured into a large Erlenmeyer flask containing solid sodium bicarbonate and ice. The reaction was neutralized (pH 7) and then extracted with EtOAc (5×150 mL). The combined organic extracts were washed with water, NaHCO3, brine, dried (Na2SO4), filtered and concentrated. The crude product was purified by flash chromatography (0-80% EtOAc/Heptane) to afford 8.0 g of methyl 4-oxo-1,4,5,6-tetrahydrocyclopenta[b]pyrrole-2-carboxylate (86%). 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 2.93-2.98 (m, 2H), 2.99-3.04 (m, 2H), 3.90 (s, 3H), 6.98 (d, J=1.71 Hz, 1H), 9.42 (br s, 1H); LCMS-MS (ESI+) 180.0 (M+H).

1. additionwith occasional mixing with a large spatula
2. additionthe mixture was carefully poured into a large Erlenmeyer flask
3. extractionextracted with EtOAc (5×150 mL)
4. washThe combined organic extracts were washed with water, NaHCO3, brine
5. dry with materialdried (Na2SO4)
6. filtrationfiltered
7. concentrationconcentrated
8. customThe crude product was purified by flash chromatography (0-80% EtOAc/Heptane)