Hydrochloric Acid → Methyl 4-ethynyl-3-nitrobenzoate

Participants

Reaction Conditions

Reaction Steps

15 g (0.054 mol) Methyl 4-(2-trimethylsilyl)ethynyl-3-nitrobenzoate (Compound III) and 225 ml tetrahydrofuran were added into a reaction flask, and started to stir, and cooled to −20 to −25° C., then 35 ml solution of 7.1 g (0.027 mol) tetrabutylammonium fluoride in tetrahydrofuran was added dropwise, and continued to react for 20 min after completing the dropwise addition. After the completion of the reaction monitored by TLC, the pH was adjusted to 4˜5 by adding 0.5 M hydrochloric acid. The mixture was concentrated under reduced pressure to evaporated most of the tetrahydrofuran, and then extracted with 300 ml ethyl acetate, the organic layer was washed with water for three times, dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated to dryness, to obtain about 10.5 g crude product, which was separated by column chromatography to obtain methyl 4-ethynyl-3-nitrobenzoate (compound II-1), 7.3 g (0.036 mol), yield 65.8%.

Provenance & Evidence