反应详情

The ester of example 2 (0.33 g, 1 mmol) was reacted with 4% NaOH (9 ml) for 3 h at room temperature. The mixture was cooled in an ice bath and the pH was adjusted to 1 with 4M hydrochloric acid. The precipitate was filtered off, washed with water and recrystallized from acetic acid to afford 0.21 g (70%) of the title compound. M.p. >320° C. 1H-NMR (DMSO-d6): 4.86 (s, 1H), 7.29 (m, 3H), 12.24 (s, 1H), 13.28 (br.s, 1H).

1. temperatureThe mixture was cooled in an ice bath
2. filtrationThe precipitate was filtered off
3. washwashed with water
4. customrecrystallized from acetic acid