Hydrochloric Acid → 4-Oxo-3,4-dihydrophthalazine-1-carboxylic acid

HRID 2119301Notes

Reaction equation

HRID 2119301 reaction equation
[CH:1]1[C:10]2[C:5](=[CH:6]C=C[CH:9]=2)[CH:4]=[CH:3][CH:2]=1.[C:11]([O-:14])([O-])=[O:12].[K+].[K+].[O-:17][Mn](=O)(=O)=O.[K+].S(O)(O)(=O)=O.[NH2:28][NH2:29].Cl>O>[C:6]1(=[O:17])[C:5]2[C:10](=[CH:1][CH:2]=[CH:3][CH:4]=2)[C:9]([C:11]([OH:14])=[O:12])=[N:29][NH:28]1

Participants

7

Reactant 5

HCID 313Hydrochloric AcidHCID 931NaphthaleneHCID 11430Potassium CarbonateHCID 24842Hydrazine SulfateHCID 516875Potassium Permanganate

Product 1

HCID 7768554-Oxo-3,4-dihydrophthalazine-1-carboxylic acid

Reagents, catalysts & solvents 1

HCID 962WaterSolvent2×

Conditions

Temperature
60 °C

Procedure

A mixture of 400 g (3.12 mol) naphthalene and 96.05 g (0.695 mol) K2CO3 in 6.66 l water is heated to 60° C. A 75° C. solution of 2480 g (15.69 mol) KMnO4 in 13.30 l water is added dropwise with occasional cooling (70° C.). Stirring is continued without heating until the exothermy subsides (about 2 h) and heating is then resumed for 5 h to 80° C. After cooling to RT, the mixture is filtered through Celite and the residue washed with water. To the slightly yellow, clear filtrate, 288 g (2.21 mol) hydrazine sulfate is added and the mixture heated for 2 h to 70° C. The cooled reaction solution is adjusted to pH 1 with conc. HCl solution, at which the product precipitates out. Cooling to 15° C., filtration via a nutsch filter and washing with water yield the title compound, m.p. 256-257° C.; 1H-NMR (DMSO-d6) 8.57 (d, 1H), 8.30 (d, 1H), 7.95 (m, 2H); FAB-MS (M+H)+=191.

Workup

  1. temperaturewith occasional cooling (70° C.)
  2. temperaturewithout heating until the exothermy subsides (about 2 h)
  3. temperatureheating
  4. temperatureAfter cooling to RT
  5. filtrationthe mixture is filtered through Celite
  6. washthe residue washed with water
  7. temperaturethe mixture heated for 2 h to 70° C
  8. customThe cooled reaction solution
  9. customprecipitates out
  10. temperatureCooling to 15° C.
  11. filtrationfiltration via
  12. filtrationa nutsch filter
  13. washwashing with water

Sources & evidence

ORD record
ord-e168e7952f80491189f035af76ad9fb0
Source dataset
uspto-grants-2004_02
Patent number
US06686347B2

Reaction notes

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