Lithium Hydroxide → Phthalazine-5-carboxylic acid

HRID 2075354Notes

Reaction equation

HRID 2075354 reaction equation
[CH:1]1[C:10]2[CH:9]=[CH:8][CH:7]=[C:6]([C:11]([O:13]C)=[O:12])[C:5]=2[CH:4]=[N:3][N:2]=1.[OH-].[Li+].C1COCC1>O>[CH:1]1[C:10]2[CH:9]=[CH:8][CH:7]=[C:6]([C:11]([OH:13])=[O:12])[C:5]=2[CH:4]=[N:3][N:2]=1

Participants

5

Reactant 3

HCID 3939Lithium HydroxideHCID 8028TetrahydrofuranHCID 57991940HCID 57991940, compound

Product 1

HCID 57991901Phthalazine-5-carboxylic acid

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

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.

Workup

  1. customAfter removal of THF
  2. customwas formed
  3. filtrationThe precipitate was filtered

Sources & evidence

ORD record
ord-69b4f3c42cb54857a9fd9d355becf7e7
Source dataset
uspto-grants-2011_04
Patent number
US07919504B2

Reaction notes

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