Hydrogen Bromide → HCID 19610855, compound

HRID 1602210Notes

Reaction equation

HRID 1602210 reaction equation
[O:1]=[C:2]1[C:18]2[C:17]([N+]([O-])=O)=[CH:16][CH:15]=[CH:14][C:13]=2[C:5]2[N:6]=[C:7]3[CH:12]=[CH:11][CH:10]=[CH:9][N:8]3[C:4]=2[C:3]1=[O:22].O.NN.N([O-])=O.[Na+].[BrH:30]>C(O)C.ClCCl.[Pd].[Cu]Br.O>[Br:30][C:17]1[C:18]2[C:2](=[O:1])[C:3](=[O:22])[C:4]3[N:8]4[CH:9]=[CH:10][CH:11]=[CH:12][C:7]4=[N:6][C:5]=3[C:13]=2[CH:14]=[CH:15][CH:16]=1

Participants

10

Reactant 4

HCID 260Hydrogen BromideHCID 24654Hydrazine hydrate (1:1)2×HCID 19610862HCID 19610862, compoundHCID 23668193Sodium Nitrite

Product 1

HCID 19610855HCID 19610855, compoundYield 25%

Reagents, catalysts & solvents 5

HCID 23938PalladiumCatalystHCID 24593copper(I) bromideCatalystHCID 702EthanolSolventHCID 962WaterSolventHCID 6344DichloromethaneSolvent

Conditions

Temperature
-15 °C

Procedure

A catalytic quantity of palladium on 10% carbon is added to an orange suspension of 110 mg (0.37 mmol, 1 eq) of 5,6-dihydro-5,6-dioxo-4-nitro-naphtho[1',2':4,5]imidazo[1,2-a]pyridine in ethanol under argon and the mixture is brought to reflux. 36.3 μL of hydrazine monohydrate (0.37 mmol, 1 eq) are then added. The reaction mixture immediately becomes violet. After 30 min, 36.3 μL of hydrazine monohydrate (0.37 mmol, 1 eq) are added. After 1 h of reaction, the reaction mixture is allowed to return to ambient temperature and the brown-violet precipitate is filtered through dried cotton and solubilized in 15 mL of conc. hydrobromic acid. This solution is cooled to -15° C., then a solution consisting of 64 mg (0.93 mm mmol, 2.5 eq) of sodium nitrite and 5 mL of distilled water is added dropwise. The medium is left under agitation at this temperature for 1.5 h. The reaction medium is added dropwise to a solution cooled to -5° C., consisting of 21 mg (0.15 mmol, 0.4 eq) of copper(I) bromide and 5 mL of conc. hydrobromic acid. A violet solution is obtained and its agitation is continued for 2.5 h. The reaction medium is then diluted in dichloromethane, washed successively with a saturated solution of sodium carbonate, then with distilled water. The organic phase is extracted, dried on sodium sulfate and evaporated to dryness. The raw product is purified on preparation plates (support silica, eluant: dichloromethane/methanol, 95/5) to produce 30 mg of 4-bromo-5,6-dihydro-5,6-dioxo-naphtho[1',2':4,5]imidazo[1,2-a] pyridine in the form of yellow crystals.

Workup

  1. temperatureto reflux
  2. customAfter 1 h of reaction
  3. customto return to ambient temperature
  4. filtrationthe brown-violet precipitate is filtered
  5. customthrough dried cotton
  6. additionis added dropwise
  7. waitThe medium is left under agitation at this temperature for 1.5 h
  8. additionThe reaction medium is added dropwise to a solution
  9. temperaturecooled to -5° C.
  10. customA violet solution is obtained
  11. waitits agitation is continued for 2.5 h
  12. washwashed successively with a saturated solution of sodium carbonate
  13. extractionThe organic phase is extracted
  14. customdried on sodium sulfate
  15. customevaporated to dryness
  16. customThe raw product is purified on preparation plates (support silica, eluant: dichloromethane/methanol, 95/5)

Sources & evidence

ORD record
ord-85a83757e07e474797e02eb89730da83
Source dataset
uspto-grants-1999_11
Patent number
US05981544

Reaction notes

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