Hydrochloric Acid → 6-Mesityl-1,3,4,7-tetramethyl-2,3-dihydro-1h-pyrazolo[5,1-b]purin-2-one

HRID 584826

Reaction equation

HRID 584826 reaction equation
O.NN.[NH2:4][C:5]1[N:10]2[N:11]=[C:12]([CH3:23])[C:13]([C:14]3[C:19]([CH3:20])=[CH:18][C:17]([CH3:21])=[CH:16][C:15]=3[CH3:22])=[C:9]2[N:8]=[C:7]([CH3:24])[C:6]=1C(OCC)=O.Cl.N([O-])=O.[Na+].[H-].[Na+].[CH3:37]I.[CH3:39][N:40](C)[CH:41]=[O:42]>C(O)C.O>[C:15]1([CH3:22])[CH:16]=[C:17]([CH3:21])[CH:18]=[C:19]([CH3:20])[C:14]=1[C:13]1[C:12]([CH3:23])=[N:11][N:10]2[C:5]3[N:4]([CH3:37])[C:41](=[O:42])[N:40]([CH3:39])[C:6]=3[C:7]([CH3:24])=[N:8][C:9]=12

Participants

10

Reactant 7

HCID 313Hydrochloric AcidHCID 6228DimethylformamideHCID 6328Methyl iodideHCID 24654Hydrazine hydrate (1:1)HCID 24758Sodium hydrideHCID 22249773Ethyl 7-amino-mesityl-2,5-dimethylpyrazolo[1,5-a]pyrimidin-6-carboxylateHCID 23668193Sodium Nitrite

Product 1

HCID 222496106-Mesityl-1,3,4,7-tetramethyl-2,3-dihydro-1h-pyrazolo[5,1-b]purin-2-one

Reagents, catalysts & solvents 2

HCID 702EthanolSolvent2×HCID 962WaterSolvent2×

Procedure

Hydrazine monohydrate (5 mL) was added to a solution of ethyl 7-amino-3-mesityl-2,5-dimethylpyrazolo[1,5-a]pyrimidin-6-carboxylate (809 mg, 2.30 mmol) in ethanol (30 mL), followed by heating under reflux for eight hours. The reaction mixture was evaporated as it was, to give a crude compound. A 10% aqueous solution of hydrogen chloride was added to a solution of the crude compound in ethanol (25 mL) under ice-cooling, and a solution of sodium nitrite (177 mg, 2.53 mmol) in water (10 mL) was gradually added dropwise. After one hour, a temperature was raised to room temperature and the mixture was stirred for 1five hours. The reaction mixture was evaporated as it was, water was added, and the resulting solid was dried, to give a crude compound (571 mg). Sodium hydride (27 mg, 0.66 mmol) was added to a solution of the crude compound (107 mg, 0.33 mmol) in N,N-dimethylformamide (5 mL) at room temperature. After 30 minutes, methyl iodide (0.052 mL, 0.83 mmol) was added, followed by stirring at the same temperature for one hour. Water was added under ice-cooling, followed by extracting with ether. The organic layer was washed with brine, dried over anhydrous magnesium sulfate and evaporated. The residue was purified by silica gel column chromatography (25% ethyl acetate/hexane), to obtain the title compound (65 mg) as brown crystals.

Workup

  1. temperatureby heating
  2. temperatureunder reflux for eight hours
  3. customThe reaction mixture was evaporated as it
  4. customto give a crude compound
  5. temperaturecooling
  6. customThe reaction mixture was evaporated as it
  7. additionwater was added
  8. customthe resulting solid was dried
  9. customto give a crude compound (571 mg)
  10. waitAfter 30 minutes
  11. stirringby stirring at the same temperature for one hour
  12. temperaturecooling
  13. extractionby extracting with ether
  14. washThe organic layer was washed with brine
  15. dry with materialdried over anhydrous magnesium sulfate
  16. customevaporated
  17. customThe residue was purified by silica gel column chromatography (25% ethyl acetate/hexane)

Sources & evidence

ORD record
ord-a6b3fa4c151d4d49b084771233bc99c5
Source dataset
uspto-grants-2005_08
Patent number
US06927221B2

Linked notes

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