Benzoic acid, 2-hydroxy-3,5-dinitro- → 3,5-Diamino-2-hydroxybenzoic acid

HRID 1024142Notes

Reaction equation

HRID 1024142 reaction equation
[N+:1]([C:4]1[CH:12]=[C:11]([N+:13]([O-])=O)[CH:10]=[C:6]([C:7]([OH:9])=[O:8])[C:5]=1[OH:16])([O-])=O>CO>[NH2:1][C:4]1[CH:12]=[C:11]([NH2:13])[CH:10]=[C:6]([C:7]([OH:9])=[O:8])[C:5]=1[OH:16]

Participants

3

Reactant 1

HCID 11873Benzoic acid, 2-hydroxy-3,5-dinitro-

Product 1

HCID 157880803,5-Diamino-2-hydroxybenzoic acidYield 117.3%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Conditions

Temperature
85 °C

Procedure

In an autoclave, 20 g of the crude DNSA produced in the above Production Example 4 was dissolved in 150 mL methanol. The solution was degassed by purging nitrogen for 10 minutes, and slowly added with 19.5 g of 98% conc. sulfuric acid and then added with 250 mg of catalyst Pd/C. The autoclave was sealed and bubbled with hydrogen at a pressure of 7 kg/cm2 for further reacting about 12 to 16 hours. After hydrogen was no longer consumed, the pressure in the autoclave was released to normal pressure and the suspended solid in the autoclave was taken out and filtered. The resultant solid was mixed with 600 g of pure water and heated at 85° C. to allow solid dissolving completely. The resultant solution was hot filtered to filter the hydrogenation catalyst off. The filtered solution was distilled under reduced pressure with recovery pure water until all solids were solidified. The solid was added with 450 mL iso-propanol to subject to recrytalization to obtain 17.3 g of product 3,5-diaminoalicylic acid (DASA), m.p.=246.7° C.

Workup

  1. customThe solution was degassed
  2. customby purging nitrogen for 10 minutes
  3. additionslowly added with 19.5 g of 98% conc. sulfuric acid
  4. additionadded with 250 mg of catalyst Pd/C
  5. customThe autoclave was sealed
  6. custombubbled with hydrogen at a pressure of 7 kg/cm2
  7. customAfter hydrogen was no longer consumed
  8. filtrationfiltered
  9. additionThe resultant solid was mixed with 600 g of pure water
  10. dissolutiondissolving completely
  11. filtrationThe resultant solution was hot filtered
  12. filtrationto filter the hydrogenation catalyst off
  13. distillationThe filtered solution was distilled under reduced pressure with recovery pure water until all solids
  14. additionThe solid was added with 450 mL iso-propanol

Sources & evidence

ORD record
ord-8770ecb6803e4d1c88044511de88f934
Source dataset
uspto-grants-2014_05
Patent number
US08722758B2

Reaction notes

Loading…