2-Amino-3-chloro-1,4-naphthoquinone → 2-(2-Chlorophenyl)naphth[2,3-d]oxazole-4,9-dione

HRID 1385204Notes

Reaction equation

HRID 1385204 reaction equation
[NH2:1][C:2]1[C:3](=[O:14])[C:4]2[C:9]([C:10](=[O:13])[C:11]=1Cl)=[CH:8][CH:7]=[CH:6][CH:5]=2.[Cl:15][C:16]1[CH:24]=[CH:23][CH:22]=[CH:21][C:17]=1[C:18](Cl)=[O:19]>O1CCOCC1>[Cl:15][C:16]1[CH:24]=[CH:23][CH:22]=[CH:21][C:17]=1[C:18]1[O:19][C:11]2[C:10](=[O:13])[C:9]3[CH:8]=[CH:7][CH:6]=[CH:5][C:4]=3[C:3](=[O:14])[C:2]=2[N:1]=1

Participants

4

Reactant 2

HCID 177482-Amino-3-chloro-1,4-naphthoquinoneHCID 691102-Chlorobenzoyl chloride

Product 1

HCID 153458162-(2-Chlorophenyl)naphth[2,3-d]oxazole-4,9-dioneYield 67.3%

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Procedure

To a solution of 5 g (24 mmol) of 2-amino-3-chloro-1,4-dihydro-1,4-dioxonaphthalene in 60 mL of dioxane, 15.3 mL (120 mmol) of 2-chlorobenzoic acid chloride are added; after 5 min of stirring, 0.5 mL of concentrated sulfuric is added. The reaction mixture is heated to reflux for 4 h, and the precipitate obtained after evaporation of the dioxane at a reduced pressure is dissolved in 200 mL of dichloromethane. To this solution, 100 mL of a cold 10N sodium hydroxide solution are added. The mixture is stirred for 2 h. The organic phase is then extracted, washed several times with water and dried over calcium chloride. The solid residue obtained after evaporation of the solvent is purified on a medium-pressure column (support: silica; eluant: dichloromethane/heptane, 40/60). The product obtained is recrystallized after color removal in a heptane/dichloromethane mixture (1/1) to produce 5 g of 2-(2-chlorophenyl)-4,9-dihydro-4,9-dioxo-naphtho[2,3-d]oxazole in the form of light yellow crystals.

Workup

  1. addition0.5 mL of concentrated sulfuric is added
  2. temperatureThe reaction mixture is heated
  3. temperatureto reflux for 4 h
  4. customthe precipitate obtained
  5. customafter evaporation of the dioxane at a reduced pressure
  6. dissolutionis dissolved in 200 mL of dichloromethane
  7. additionTo this solution, 100 mL of a cold 10N sodium hydroxide solution are added
  8. stirringThe mixture is stirred for 2 h
  9. extractionThe organic phase is then extracted
  10. washwashed several times with water
  11. dry with materialdried over calcium chloride
  12. customThe solid residue obtained
  13. customafter evaporation of the solvent
  14. customis purified on a medium-pressure column (support: silica; eluant: dichloromethane/heptane, 40/60)
  15. customThe product obtained
  16. customis recrystallized
  17. customafter color removal in a heptane/dichloromethane mixture (1/1)

Sources & evidence

ORD record
ord-887e56495bc84146a6762f7625ca86e6
Source dataset
uspto-grants-2001_07
Patent number
US06262095B1

Reaction notes

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