Bromine → 3-Bromo-1-methyl-5-(pyrazin-2-yl)pyridin-2(1H)-one

HRID 1981512Notes

Reaction equation

HRID 1981512 reaction equation
[Br:1]Br.[CH3:3][N:4]1[CH:9]=[C:8]([C:10]2[CH:15]=[N:14][CH:13]=[CH:12][N:11]=2)[CH:7]=[CH:6][C:5]1=[O:16]>C(O)(=O)C>[Br:1][C:6]1[C:5](=[O:16])[N:4]([CH3:3])[CH:9]=[C:8]([C:10]2[CH:15]=[N:14][CH:13]=[CH:12][N:11]=2)[CH:7]=1

Participants

4

Reactant 2

HCID 24408BromineHCID 136450981-Methyl-5-(pyrazin-2-yl)pyridin-2(1H)-one

Product 1

HCID 136450993-Bromo-1-methyl-5-(pyrazin-2-yl)pyridin-2(1H)-one

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

2.5 ml of bromine are added to a solution of 1-methyl-5-(2-pyrazinyl)-2-pyridone (3.5 g) in glacial acetic acid (150 ml). The reaction mixture is filtered and the filtered solid washed with glacial acetic acid. The filtrate is evaporated in vacuum and the oily residue treated with aqueous sodium bisulfate. The filtered solid is suspended in 250 ml of distilled H2O to which has been added 7 g of sodium bisulfate. A solution of saturated potassium carbonate is added to the suspension to bring the pH back to 6.4. The resulting solid is filtered, washed with H2O and air dried. The same sodium bisulfate procedure is followed with the oily residue obtained from the evaporated filtrate. The solids are combined, recrystallized from isopropanol with decolorizing charcoal added and filtered off hot. The recrystallized solid is suspended in 50 ml of H2O containing 10 g of sodium bisulfate and stirred overnight. The suspended solid is filtered and washed with distilled H2O, recrystallized from isopropanol, filtered, washed with ether and air dried, resulting in the desired 3-bromo-1-methyl-5-(2-pyrazinyl)-2-pyridone, M.P. 196°-197° C.

Workup

  1. filtrationThe reaction mixture is filtered
  2. washthe filtered solid washed with glacial acetic acid
  3. customThe filtrate is evaporated in vacuum
  4. additionthe oily residue treated with aqueous sodium bisulfate
  5. additionhas been added 7 g of sodium bisulfate
  6. additionA solution of saturated potassium carbonate is added to the suspension
  7. filtrationThe resulting solid is filtered
  8. washwashed with H2O and air
  9. customdried
  10. customobtained from the evaporated filtrate
  11. customrecrystallized from isopropanol with decolorizing charcoal
  12. additionadded
  13. filtrationfiltered off hot
  14. filtrationThe suspended solid is filtered
  15. washwashed with distilled H2O
  16. customrecrystallized from isopropanol
  17. filtrationfiltered
  18. washwashed with ether and air
  19. customdried

Sources & evidence

ORD record
ord-5941c95a43ef4f5f95f694c32a582033
Source dataset
uspto-grants-1986_06
Patent number
US04593028

Reaction notes

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