Sodium Carbonate → 2-(benzyloxy)-6,7-dihydropyrazolo[1,5-a]pyrazin-4(5H)-one

HRID 571724Notes

Reaction equation

HRID 571724 reaction equation
[CH2:1]([O:8][C:9]1[CH:13]=[C:12](C(OCC)=O)[N:11]([CH2:19][CH2:20][NH:21][C:22]([O:24]C(C)(C)C)=O)[N:10]=1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C([O-])([O-])=O.[Na+].[Na+]>Cl.O1CCOCC1.O>[CH2:1]([O:8][C:9]1[CH:13]=[C:12]2[C:22](=[O:24])[NH:21][CH2:20][CH2:19][N:11]2[N:10]=1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

6

Reactant 2

HCID 10340Sodium CarbonateHCID 86706489ethyl 3-(benzyloxy)-1-{2-[(tert-butoxycarbonyl)amino]ethyl}-1H-pyrazole-5-carboxylate

Product 1

HCID 727147872-(benzyloxy)-6,7-dihydropyrazolo[1,5-a]pyrazin-4(5H)-oneYield 99%

Reagents, catalysts & solvents 3

HCID 313Hydrochloric AcidSolventHCID 962WaterSolventHCID 312751,4-DioxaneSolvent

Procedure

Ethyl 3-(benzyloxy)-1-{2-[(tert-butoxycarbonyl)amino]ethyl}-1H-pyrazole-5-carboxylate (0.51 g, 1.31 mmol) was dissolved in a 4 M solution of HCl in 1,4-dioxane (6.53 mL). The mixture was stirred at room temperature for 1 hour and then basified with a saturated solution of Na2CO3. The mixture was stirred at room temperature for 1 hour, diluted with water and extracted with DCM. The organic layer was separated, dried (Na2SO4), filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; 7 M solution of ammonia in MeOH in DCM 0/100 to 10/90). The desired fractions were collected and the solvents evaporated in vacuo to yield 2-(benzyloxy)-6,7-dihydropyrazolo[1,5-a]pyrazin-4(5H)-one (0.31 g, 99% yield) as a white solid.

Workup

  1. stirringThe mixture was stirred at room temperature for 1 hour
  2. extractionextracted with DCM
  3. customThe organic layer was separated
  4. dry with materialdried (Na2SO4)
  5. filtrationfiltered
  6. customthe solvents evaporated in vacuo
  7. customThe crude product was purified by flash column chromatography (silica; 7 M solution of ammonia in MeOH in DCM 0/100 to 10/90)
  8. customThe desired fractions were collected
  9. customthe solvents evaporated in vacuo

Sources & evidence

ORD record
ord-8f052d13990e4e9e8476f1d0aa6169ad
Source dataset
uspto-grants-2015_05
Patent number
US09029366B2

Reaction notes

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