Sulfuric Acid → 3,5-Dibromopyrazin-2(1H)-one

HRID 2073933Notes

Reaction equation

HRID 2073933 reaction equation
N[C:2]1[C:7]([Br:8])=[N:6][C:5]([Br:9])=[CH:4][N:3]=1.S(=O)(=O)(O)[OH:11].N([O-])=O.[Na+]>>[Br:8][C:7]1[C:2](=[O:11])[NH:3][CH:4]=[C:5]([Br:9])[N:6]=1

Participants

4

Reactant 3

HCID 1118Sulfuric Acid2×HCID 6200042-Amino-3,5-dibromopyrazineHCID 23668193Sodium Nitrite

Product 1

HCID 167408633,5-Dibromopyrazin-2(1H)-one

Conditions

Temperature
20 °C

Procedure

A solution of 12.65 g of 2-amino-3,5-dibromo-pyrazine and 18.5 ml of 96% sulfuric acid is added dropwise to a solution of 3.45 g of sodium nitrite and 27.5 ml of 96% sulfuric acid at 0° to 5° C. The mixture is then allowed to warm to 20° C. in the course of 2 hours and is stirred at 20°-25° C. for a further 15 hours. The reaction mixture is poured into ice and the product is filtered off, washed with ice-water and dried to give 5.8 g of 3,5-dibromo-pyrazin-2-one.

Workup

  1. additionThe reaction mixture is poured into ice
  2. filtrationthe product is filtered off
  3. washwashed with ice-water
  4. customdried

Sources & evidence

ORD record
ord-8beec52c343f453ca6637e13f9329e40
Source dataset
uspto-grants-1990_04
Patent number
US04920223

Reaction notes

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