Hydrochloric Acid → 4,6-Dimethyl-1H-pyrazolo[4,3-d]pyrimidine-5,7(4H,6H)-dione

HRID 467862Notes

Reaction equation

HRID 467862 reaction equation
[NH2:1][C:2]1[C:3](=[O:12])[N:4]([CH3:11])[C:5](=[O:10])[N:6]([CH3:9])[C:7]=1[CH3:8].Cl.[N:14]([O-])=O.[Na+]>O>[CH3:9][N:6]1[C:7]2[CH:8]=[N:14][NH:1][C:2]=2[C:3](=[O:12])[N:4]([CH3:11])[C:5]1=[O:10]

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 816935AB-323/25048145HCID 23668193Sodium Nitrite

Product 1

HCID 537352994,6-Dimethyl-1H-pyrazolo[4,3-d]pyrimidine-5,7(4H,6H)-dione

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

To a stirred solution of Step 1 intermediate (4.0 g, 23.634 mmol) in a mixture of ice (24 g) and concentrated HCl (5 ml) was added a solution of sodium nitrite (1.42 g, 20.580 mmol) in water (5 ml). The resulting suspension was stirred below 10° C. for 30 min. The solid formed at this stage was removed by filtration and the filtrate was added slowly with continuous stirring to 20% aq. NaOH (20 ml) by maintaining the temperature below 10° C. After addition the basic solution was filtered and neutralized with hydrochloric acid (5 N HCl). The precipitate separated was filtered and dried to get 300 mg of the product as dark orange solid; 1H NMR (300 MHz, DMSO-d6): δ 3.45 (s, 3H), 3.52 (s, 3H), 7.53 (s, 1H).

Workup

  1. customThe solid formed at this stage
  2. customwas removed by filtration
  3. additionthe filtrate was added slowly
  4. stirringwith continuous stirring to 20% aq. NaOH (20 ml)
  5. temperatureby maintaining the temperature below 10° C
  6. additionAfter addition the basic solution
  7. filtrationwas filtered
  8. customThe precipitate separated
  9. filtrationwas filtered
  10. customdried

Sources & evidence

ORD record
ord-c3e825c35290488c9429968106d12426
Source dataset
uspto-grants-2014_01
Patent number
US08623880B2

Reaction notes

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