Table 2.
Entry | Catalyst | Reaction conditions | Yield (%) * | ||
---|---|---|---|---|---|
10b | 15b | 14b | |||
1 | NaOH a | CH3OH/H2O, Reflux, 30 h | trace | - | - |
2 | NaOH a | H2O, Reflux, 30 h | trace | - | - |
3 | HCl b | 1,4-Dioxane, Reflux, 16 h | - | 20 | 66 |
4 | H2SO4 c | H2O, 100 °C, 16 h | - | 23 | 72 |
5 | H2O2 d/NaOH a | H2O, 80 h, 20 h | 7 | - | - |
Catalyst concentration: a 2 M; b 37%; c 40%; d 30%. * Isolated yield.