Hydrogen Bromide → 3,4-Dihydroxy-5-nitrobenzaldehyde

HRID 274431

Reaction equation

HRID 274431 reaction equation
[OH:1][C:2]1[C:9]([N+:10]([O-:12])=[O:11])=[CH:8][C:5]([CH:6]=[O:7])=[CH:4][C:3]=1[O:13]C.Br>C(Cl)Cl>[OH:13][C:3]1[CH:4]=[C:5]([CH:8]=[C:9]([N+:10]([O-:12])=[O:11])[C:2]=1[OH:1])[CH:6]=[O:7]

Participants

4

Reactant 2

HCID 260Hydrogen BromideHCID 811345-Nitrovanillin

Product 1

HCID 57489573,4-Dihydroxy-5-nitrobenzaldehyde

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

17.1 g of 4-hydroxy-3-methoxy-5-nitrobenzaldehyde are treated with 170 ml of constant-boiling hydrobromic acid and heated under reflux for 3.5 hours. After cooling the separated precipitate is filtered under suction, washed twice with ice-water and taken up in ethyl acetate. The organic phase is washed twice with 50 ml of sodium chloride solution each time, dried over magnesium sulfate and evaporated in a water-jet vacuum. The crystals obtained are taken up in methylene chloride, whereupon the solution is filtered over a ten-fold amount of silica gel. The material obtained is crystallized from ethyl acetate/isopropyl ether. There is obtained 3,4-dihydroxy-5-nitrobenzaldehyde in the form of yellow crystals of m.p. 142°-143°.

Workup

  1. temperatureheated
  2. temperatureunder reflux for 3.5 hours
  3. temperatureAfter cooling the separated precipitate
  4. filtrationis filtered under suction
  5. washwashed twice with ice-water
  6. washThe organic phase is washed twice with 50 ml of sodium chloride solution each time
  7. dry with materialdried over magnesium sulfate
  8. customevaporated in a water-jet vacuum
  9. customThe crystals obtained
  10. filtrationis filtered over a ten-fold amount of silica gel
  11. customThe material obtained
  12. customis crystallized from ethyl acetate/isopropyl ether

Sources & evidence

ORD record
ord-abb4814a8f9b43979a8172da63570498
Source dataset
uspto-grants-1995_02
Patent number
US05389653

Linked notes

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