Oxalic acid dihydrate → HCID 178516987, compound

HRID 1165805Notes

Reaction equation

HRID 1165805 reaction equation
[NH2:1][C:2]1[C:11]2[C:6](=[C:7]([Br:12])[CH:8]=[CH:9][CH:10]=2)[CH:5]=[CH:4][C:3]=1[NH2:13].O.O.[C:16](O)(=[O:20])[C:17](O)=[O:18]>Cl>[Br:12][C:7]1[C:6]2[CH:5]=[CH:4][C:3]3[N:13]=[C:17]([OH:18])[C:16]([OH:20])=[N:1][C:2]=3[C:11]=2[CH:10]=[CH:9][CH:8]=1

Participants

4

Reactant 2

HCID 61373Oxalic acid dihydrateHCID 19861000HCID 19861000, compound

Product 1

HCID 178516987HCID 178516987, compoundYield 67.1%

Reagents, catalysts & solvents 1

HCID 313Hydrochloric AcidSolvent

Conditions

Temperature
25 °C

Procedure

A mixture of 1,0 g (4,2 mmol) 1,2-diamino-5-bromonaphthalene and 1,2 g (9,5 mmol) oxalic acid dihydrate in 20 ml 4 N hydrochloric acid was refluxed for 2,5 h. After cooling to 25° C., the precipitate was filtered off and washed with water. The crude product was dissolved in 200 ml 2 N sodium hydroxide, and reprecipitated with 4N hydrochloric acid (to pH 1-2) to give 820 mg (67%) of pure 7-bromo-2,3-dihydroxybenzo(f)quinoxaline, m.p. >300° C.1H NMR (DMSO-d6 ): 8,6 (1H,d), 7,8 (1H,d), 7,7 (1H,d), 7,4 (1H,d), 7,3 (1H,d).

Workup

  1. temperaturewas refluxed for 2,5 h
  2. filtrationthe precipitate was filtered off
  3. washwashed with water
  4. dissolutionThe crude product was dissolved in 200 ml 2 N sodium hydroxide
  5. customreprecipitated with 4N hydrochloric acid (to pH 1-2)

Sources & evidence

ORD record
ord-cd55531cc25544d38a51035cb0d765d0
Source dataset
uspto-grants-1990_03
Patent number
US04912108

Reaction notes

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