Methanol → 5H-Indeno[1,2-b]pyridine-5-carboxylic acid, 5-hydroxy-, methyl ester

Participants

Reaction Steps

To a stirred solution of sodium (1.1 eq, 60.1 mmol. 1.38 g) in 150 mL dry methanol was added a solution of 5-hydroxy-5H-indeno[1,2-b]pyridine-5-carboxylic acid methol ester (22) (12.3 g, 54.6 mmol) in 50 mL dry methanol. The solution was cooled in ice and, after 15 min., a flow of dry oxygen was begun and continued for 1 h. Then the reaction mixture was poured into a solution of 12 g sodium bisulfite in 200 mL water. After 30 min. the mixture was evaporated to dryness. The resulting solid was triturated with 2×100 mL acetone and filtered. The remaining inorganic salts were removed by filtration. The filtrate was evaporated to yield 24.2 g wet pink solid of (23). Drying in vacuo over phosphorus pentaoxide yielded 12.5 g crude (23). Recrystallization from ethyl acetate yielded two crops 8.06 g (61%) and 2.54 g (19%) of (23).

Provenance & Evidence