4,7-Dibromo-2,1,3-benzothiadiazole → 3,6-Dibromobenzene-1,2-diamine

HRID 43218

Reaction equation

HRID 43218 reaction equation
[BH4-].[Na+].[Br:3][C:4]1[C:9]2=[N:10]S[N:12]=[C:8]2[C:7]([Br:13])=[CH:6][CH:5]=1>CCO>[Br:3][C:4]1[CH:5]=[CH:6][C:7]([Br:13])=[C:8]([NH2:12])[C:9]=1[NH2:10]

Participants

4

Reactant 2

HCID 6263614,7-Dibromo-2,1,3-benzothiadiazoleHCID 4311764Sodium borohydride

Product 1

HCID 118215323,6-Dibromobenzene-1,2-diamineYield 66.4%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Conditions

Temperature
30 °C

Procedure

NaBH4 (26 g, 680 mmol, 10 equiv) was added portionwise (2 h) to a vigorously stirred suspension of 4,7-dibromo-benzo[1,2,5]thiadiazole (Step 179.7) (20 g, 68.0 mmol) in EtOH (400 mL), under a nitrogen atmosphere and keeping the internal temperature below 15° C. The reaction mixture was allowed to warm to 30° C., stirred for 1 h, cooled to 5° C., quenched by addition of H2O (50 mL), and concentrated. The residue was diluted with Et2O/H2O. The resulting suspension was filtered and the filtrate extracted with Et2O. The organic phase was washed with H2O and brine, dried (Na2SO4), filtered and concentrated. The residue was triturated in hexane to provide 12 g of the title compound as a white solid: ESI-MS: 263/265/267 [M−H]−; tR=4.20 min (System 1).

Workup

  1. customthe internal temperature below 15° C
  2. temperaturecooled to 5° C.
  3. customquenched by addition of H2O (50 mL)
  4. concentrationconcentrated
  5. additionThe residue was diluted with Et2O/H2O
  6. filtrationThe resulting suspension was filtered
  7. extractionthe filtrate extracted with Et2O
  8. washThe organic phase was washed with H2O and brine
  9. dry with materialdried (Na2SO4)
  10. filtrationfiltered
  11. concentrationconcentrated
  12. customThe residue was triturated in hexane

Sources & evidence

ORD record
ord-d1709645b07944c4b9477092e0b7297b
Source dataset
uspto-grants-2013_09
Patent number
US08536175B2

Linked notes

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