Hydrazine hydrate (1:1) → 7-methoxy-4-methyl-2H-phthalazin-1-one

HRID 1471342Notes

Reaction equation

HRID 1471342 reaction equation
[C:1]([C:4]1[CH:13]=[CH:12][C:11]([O:14][CH3:15])=[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:11]1[CH:10]=[C:5]2[C:4]([C:1]([CH3:2])=[N:17][NH:18][C:6]2=[O:7])=[CH:13][CH:12]=1

Participants

5

Reactant 2

HCID 24654Hydrazine hydrate (1:1)HCID 59373119HCID 59373119, compound

Product 1

HCID 576916797-methoxy-4-methyl-2H-phthalazin-1-oneYield 95.2%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 962WaterSolvent

Conditions

Temperature
95 °C

Procedure

To a solution of methyl 2-acetyl-5-methoxybenzoate (2) (2.21 g, 10.60 mmol) in methanol (13 mL) is added hydrazine monohydrate (1.59 g, 31.80 mmol). The mixture is stirred at 95° C. under argon for 5 h, then cooled to room temperature, diluted with H2O (50 mL), and extracted with ethyl acetate (2×100 mL, 2×50 mL, and 2×30 mL). The extract is washed (brine), dried, and concentrated at reduced pressure. The residue is suspended in ethyl acetate (20 mL), heated, then cooled, and filtered to give 1.92 g (95%) of 3 as a white solid, mp 203-205° C. IR 3314, 2918, 1652, 1241 cm−1; 1H NMR (CDCl3) δ 2.60 (s, 3H, CH3), 4.01 (s, 3H, CH3O), 7.42 (dd, J=9.0, 2.7 Hz, 1H, 6-PhthH), 7.75 (d, J=9.0 Hz, 1H, 5-PhthH), 7.88 (d, J=2.7 Hz, 1H, 8-PhthH), 10.75 ppm (s, 1H, NH).

Workup

  1. temperaturecooled to room temperature
  2. extractionextracted with ethyl acetate (2×100 mL, 2×50 mL, and 2×30 mL)
  3. washThe extract is washed (brine)
  4. customdried
  5. concentrationconcentrated at reduced pressure
  6. temperatureheated
  7. temperaturecooled
  8. filtrationfiltered

Sources & evidence

ORD record
ord-a2cfd4ad42a241b586fc22de28f1609b
Source dataset
uspto-grants-2015_04
Patent number
US09012217B2

Reaction notes

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