1,5-Diazabicyclo(5,4,0)undec-5-ene → tert.butyl 2-acetylthiomethyl-hexahydro-3-oxo-1H-pyrazolo[1,2-a]pyridazine-5-carboxylate

HRID 1154052Notes

Reaction equation

HRID 1154052 reaction equation
N12CCCCC1C=NCCC2.Br[CH2:13][CH:14]1[CH2:29][N:17]2[CH2:18][CH2:19][CH2:20][CH:21]([C:22]([O:24][C:25]([CH3:28])([CH3:27])[CH3:26])=[O:23])[N:16]2[C:15]1=[O:30].[C:31]([O-:34])(=[S:33])[CH3:32].[K+].C(O)(=S)C>O1CCOCC1.CC(C)=O.ClCCl>[C:31]([S:33][CH2:13][CH:14]1[CH2:29][N:17]2[CH2:18][CH2:19][CH2:20][CH:21]([C:22]([O:24][C:25]([CH3:28])([CH3:27])[CH3:26])=[O:23])[N:16]2[C:15]1=[O:30])(=[O:34])[CH3:32]

Participants

8

Reactant 4

HCID 3141121,5-Diazabicyclo(5,4,0)undec-5-eneHCID 20435995HCID 20435995, compoundHCID 23670855Potassium ethanethioateHCID 178418634HCID 178418634, compound

Product 1

HCID 20435955tert.butyl 2-acetylthiomethyl-hexahydro-3-oxo-1H-pyrazolo[1,2-a]pyridazine-5-carboxylateYield 39%

Reagents, catalysts & solvents 3

HCID 180AcetoneSolventHCID 6344DichloromethaneSolventHCID 312751,4-DioxaneSolvent2×

Procedure

2.3 ml of 1,5-diazabicyclo[5.4.0]undec-5-ene in 10 ml of dioxan were added at 5° C. to a solution of 4.4 g of tert.butyl 2-bromomethyl-hexahydro-3-oxo-1H-pyrazolo[1,2-a]-pyridazine-5-carboxylate (diastereomer B) in 25 ml of dioxan. The mixture was left to stand at room temperature for 2 hours and then filtered. The filtrate was evaporated and the residue was dissolved in ethyl acetate. The solution was filtered through 6 g of silica gel and evaporated. The residue obtained was dissolved in 10 ml of acetone. The solution was treated with 1.6 g of potassium thioacetate and subsequently with 10 ml of thioacetic acid, whereupon the mixture was stirred overnight at room temperature. The mixture was diluted with 100 ml of dichloromethane and washed with 50 ml of saturated aqueous sodium bicarbonate. The separated organic phase was dried over magnesium sulfate and evaporated to give an oil which was chromatographed over 200 g of silica gel using diethyl ether/hexane for the elution. After recrystallization from ethyl acetate/hexane, there were obtained 1.69 g of tert.butyl 2-acetylthiomethyl-hexahydro-3-oxo-1H-pyrazolo[1,2-a]pyridazine-5-carboxylate (diastereomer A) and 0.9 g of the corresponding diastereomer B.

Workup

  1. waitThe mixture was left
  2. filtrationfiltered
  3. customThe filtrate was evaporated
  4. dissolutionthe residue was dissolved in ethyl acetate
  5. filtrationThe solution was filtered through 6 g of silica gel
  6. customevaporated
  7. customThe residue obtained
  8. washwashed with 50 ml of saturated aqueous sodium bicarbonate
  9. dry with materialThe separated organic phase was dried over magnesium sulfate
  10. customevaporated
  11. customto give an oil which
  12. customwas chromatographed over 200 g of silica gel
  13. washfor the elution
  14. customAfter recrystallization from ethyl acetate/hexane

Sources & evidence

ORD record
ord-ec6ef9589b6445d9bef7d62ff38bdbb8
Source dataset
uspto-grants-1984_12
Patent number
US04487929

Reaction notes

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