Sodium Sulfite → 5-Bromo-2,3-dimethoxypyrazine

HRID 359451Notes

Reaction equation

HRID 359451 reaction equation
[Br:1]NC(=O)CCC(N)=O.[CH3:10][O:11][C:12]1[C:17]([O:18][CH3:19])=[N:16][CH:15]=[CH:14][N:13]=1.[O-]S([O-])=O.[Na+].[Na+]>CN(C=O)C>[Br:1][C:14]1[CH:15]=[N:16][C:17]([O:18][CH3:19])=[C:12]([O:11][CH3:10])[N:13]=1

Participants

5

Reactant 3

HCID 24437Sodium SulfiteHCID 9834204N-BromosuccinamideHCID 124023092,3-Dimethoxypyrazine

Product 1

HCID 151144395-Bromo-2,3-dimethoxypyrazineYield 63.9%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent2×

Conditions

Temperature
25 °C

Procedure

A solution of 14.6 gm of N-bromosuccinamide, 32 ml of dry DMF was added to a stirred solution of 11 gm (0.078 mol) of 2,3-dimethoxypyrazine in 14 ml of DMF at 0° C. whereupon the reaction was warmed to 25° C. and stirred for 16 hours. The reaction mixture was then cooled in an ice bath and to it was added aqueous Na2SO3 to remove the bromine and this was poured into ice water. The resulting crystalline solid was filtered, triturated with water and dried to give 10.48 gm of the title compound. NMR (CDCl3)δ4.0, 4.02(2s, 6H, OCH3), 7.70(s,1H).

Workup

  1. temperatureThe reaction mixture was then cooled in an ice bath and to it
  2. customto remove the bromine
  3. additionthis was poured into ice water
  4. filtrationThe resulting crystalline solid was filtered
  5. customtriturated with water
  6. customdried

Sources & evidence

ORD record
ord-210cf2cb49814c4ab49c4612f1e1ffc8
Source dataset
uspto-grants-1991_03
Patent number
US05001123

Reaction notes

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