Potassium Nitrate → 6-Bromo-7-chloro-5-nitro-1,4-dihydro-2,3-quinoxalinedione

HRID 1781013Notes

Reaction equation

HRID 1781013 reaction equation
[Br:1][C:2]1[C:3]([N+:14]([O-:16])=[O:15])=[C:4]2[C:9](=[CH:10][C:11]=1[Cl:12])[NH:8][C:7](=[O:13])[CH:6]=[N:5]2.[N+]([O-])([O-])=[O:18].[K+]>OS(O)(=O)=O>[Br:1][C:2]1[C:3]([N+:14]([O-:16])=[O:15])=[C:4]2[C:9](=[CH:10][C:11]=1[Cl:12])[NH:8][C:7](=[O:13])[C:6](=[O:18])[NH:5]2

Participants

4

Reactant 2

HCID 24434Potassium NitrateHCID 211899856-Bromo-7-chloro-5-nitroquinoxaline-2(1H)-one

Product 1

HCID 104037516-Bromo-7-chloro-5-nitro-1,4-dihydro-2,3-quinoxalinedione

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent

Procedure

To a stirred solution of 6-bromo-7-chloro-5-nitroquinoxaline-2(1H)-one (0.025 g, 0.082 mmol, as prepared above) in conc. H2SO4 (0.5 mL) was added KNO3 (0.011 g, 0.11 mmol) and the resulting dark red solution was stirred at room temperature for 65 h. The solution was then cooled in an ice-bath and diluted with ice to a total volume of 5.0 mL. The precipitated solid was filtered, washed with water (2.0 mL) and dried under vacuum to obtain 0.019 g (72%) crude product. It was purified as follows. 0.016 g crude product was taken up in 1N NaOH (1.1 mL). The insoluble solid was centrifuged and the supernatant liquid was acidified with conc. HCl to pH ~2. The precipitated solid was filtered, washed with water (1.0 mL), and dried under vacuum to furnish 0.010 g (38%) pure (purity by HPLC>97%) title compound as a cream colored powder; m.p. 338°-343° C. (decomposed); 1H NMR (DMSO-d6): δ7.351 (s, 1H), 12.251 (s overlapped by a br s, 2H); Elemental analysis for C8H3BrClN3O4, calcd: C, 29.98%; H, 0.94%; N, 13.11%, found: C, 29.79; H, 0.77; N, 12.71.

Workup

  1. temperatureThe solution was then cooled in an ice-bath
  2. additiondiluted with ice to a total volume of 5.0 mL
  3. filtrationThe precipitated solid was filtered
  4. washwashed with water (2.0 mL)
  5. customdried under vacuum
  6. customto obtain 0.019 g (72%) crude product
  7. customIt was purified
  8. filtrationThe precipitated solid was filtered
  9. washwashed with water (1.0 mL)
  10. customdried under vacuum

Sources & evidence

ORD record
ord-94d496ef03ff467399e1d332ac63af12
Source dataset
uspto-grants-1997_05
Patent number
US05631373

Reaction notes

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