反应详情

A mixture of EXAMPLE 16A (9.91 g) and acetic anhydride (150 mL) at reflux was stirred for 16 hours, treated with additional acetic anhydride (60 mL), refluxed for 5 hours, cooled and concentrated. The concentrate was dissolved in 9:1 ethanol/ethyl acetate (100 mL), stored at 0° C. for 18 hours, and filtered. 1H NMR (300 MHz, DMSO-d6) δ 10.65 (d, 1H), 8.90 (d, 1H), 7.66 (s, 1H), 4.23 (q, 2H), 4.14 (q, 2H), 2.52 (s, 3H), 2.26 (s, 1H), 2.11 (s, 3H), 1.27 (t, 3H), 1.23 (t, 3H).

1. temperaturerefluxed for 5 hours
2. temperaturecooled
3. concentrationconcentrated
4. dissolutionThe concentrate was dissolved in 9:1 ethanol/ethyl acetate (100 mL)
5. waitstored at 0° C. for 18 hours
6. filtrationfiltered