Lithium Hydroxide → Phthalazine-5-carboxylic acid

Participants

Reaction Steps

To a 50 mL round bottom flask was added methyl phthalazine-5-carboxylate (1.0 g, 5 mmol), lithium hydroxide (0.3 g, 11 mmol), THF (4 mL) and water (4 mL). The resulting solution was stirred for 1 hour at room temperature. After removal of THF, the residue was acidified with 1N HCl until a precipitate was formed. The precipitate was filtered to provide phthalazine-5-carboxylic acid, used directly for next step. LCMS (M+H) 175.1 calc. for C9H7N2O2 175.0. 1H NMR (400 MHz, CDCl3): δ ppm 8.06 (d, J=8.41 Hz, 1H) 8.51-8.56 (d, 1H) 8.71 (d, 1H) 9.64 (s, 2H). Carboxylic acid H not detected.

Provenance & Evidence