Lithium hydroxide, monohydrate → 5-bromo-3,4-dihydro-1H-isochromene-1-carboxylic acid

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Reaction Steps

To a solution of methyl 5-bromo-3,4-dihydro-1H-isochromene-1-carboxylate (12.1 g, 42.4 mmol) in 200 mL of MeOH/THF/H2O (2/2/1) was added LiOH.H2O (5.34 g, 0.127 mol), and the mixture was stirred at ambient temperature for 30 min. The solvents were removed under vacuum, and the residue was added 100 mL of water and extracted with ether. The aqueous layer was then acidified with 4 N HCl to pH=4˜5 in ice bath, and extracted with EtOAc. The combined organic phase was washed with brine, dried over anhydrous sodium sulfate and concentrated to afford 5-bromo-3,4-dihydro-1H-isochromene-1-carboxylic acid.

Provenance & Evidence