Hydrazine hydrate (1:1) → 6-Methoxy-4-methyl-2H-phthalazin-1-one

HRID 1471350Notes

Reaction equation

HRID 1471350 reaction equation
[C:1]([C:4]1[CH:13]=[C:12]([O:14][CH3:15])[CH:11]=[CH:10][C:5]=1[C:6](OC)=[O:7])(=O)[CH3:2].O.[NH2:17][NH2:18]>CO.O>[CH3:15][O:14][C:12]1[CH:13]=[C:4]2[C:5](=[CH:10][CH:11]=1)[C:6](=[O:7])[NH:18][N:17]=[C:1]2[CH3:2]

Participants

5

Reactant 2

HCID 24654Hydrazine hydrate (1:1)HCID 59373125Methyl 2-acetyl-4-methoxybenzoate

Product 1

HCID 155226156-Methoxy-4-methyl-2H-phthalazin-1-oneYield 94.4%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 962WaterSolvent

Conditions

Temperature
95 °C

Procedure

To a solution of methyl 2-acetyl-4-methoxybenzoate (5) (2.47 g, 11.86 mmol) in methanol (14.5 mL) is added hydrazine monohydrate (1.78 g, 35.60 mmol). The mixture is stirred at 95° C. under argon for 6 h, the cooled to room temperature, diluted with H2O (50 mL), and extracted with CHCl3 (2×100 mL) and ethyl acetate (100 mL, 2×50 mL, and 2×40 mL). The extracts were washed (brine) and dried. After solvent removal at reduced pressure, the residue is suspended in ethyl acetate (30 mL), heated, cooled, and filtered to give 2.13 g (94%) of 6 as a white solid, mp 252-254° C. IR 3298, 2941, 1732, 1055 cm−1; 1H NMR (CDCl3) δ 2.58 (s, 3H, CH3), 4.00 (s, 3H, CH3O), 7.12 (d, J=1.6 Hz, 1H, 5-PhthH), 7.35 (dd, J=5.6, 1.6 Hz, 1H, 7-PhthH), 8.41 (d, J=5.6 Hz, 1H, 8-PhthH), 10.12 ppm (s, 1H, NH).

Workup

  1. temperaturethe cooled to room temperature
  2. extractionextracted with CHCl3 (2×100 mL) and ethyl acetate (100 mL, 2×50 mL, and 2×40 mL)
  3. washThe extracts were washed (brine)
  4. customdried
  5. customAfter solvent removal at reduced pressure
  6. temperatureheated
  7. temperaturecooled
  8. filtrationfiltered

Sources & evidence

ORD record
ord-e8841fa3bd1a4c258296b33c27ac499b
Source dataset
uspto-grants-2015_04
Patent number
US09012217B2

Reaction notes

Loading…