Sulfuric Acid → 2-(4-Fluorophenyl)naphtho[2,3-d]oxazole-4,9-dione

HRID 1385200Notes

Reaction equation

HRID 1385200 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.[F:15][C:16]1[CH:24]=[CH:23][C:19]([C:20](Cl)=[O:21])=[CH:18][CH:17]=1.S(=O)(=O)(O)O.CCOCC>[N+](C1C=CC=CC=1)([O-])=O>[O:14]=[C:3]1[C:2]2[N:1]=[C:20]([C:19]3[CH:23]=[CH:24][C:16]([F:15])=[CH:17][CH:18]=3)[O:21][C:11]=2[C:10](=[O:13])[C:9]2[CH:8]=[CH:7][CH:6]=[CH:5][C:4]1=2

Participants

6

Reactant 4

HCID 1118Sulfuric AcidHCID 3283Diethyl EtherHCID 177482-Amino-3-chloro-1,4-naphthoquinoneHCID 678794-Fluorobenzoyl chloride

Product 1

HCID 23073312-(4-Fluorophenyl)naphtho[2,3-d]oxazole-4,9-dioneYield 33%

Reagents, catalysts & solvents 1

HCID 7416NitrobenzeneSolvent

Procedure

To a solution of 6.22 g (30 mmol) of 2-amino-3-chloro-1,4-dihydro-1,4-dioxo-naphthalene in 60 mL of nitrobenzene, 18.00 mL (150 mmol) of 4-fluorobenzoic acid chloride are added with protection from light. After 10 min of stirring with reflux, 0.20 mL of concentrated sulfuric acid is added. After 12 h and complete cooling, ether is added to obtain a yellow precipitate which is filtered through fritted glass, washed with ether and purified on a flash column (support: silica; conditioning: heptane; eluant: dichloromethane/heptane, 60/40). The yellow powder obtained after evaporation of the solvent is uncolored, recrystallized in dichloromethane to produce 2.90 g of 4,9-dihydro-4,9-dioxo-2-(4-fluorophenyl)-naphtho[2,3-d]oxazole in the form of yellow crystals.

Workup

  1. temperaturewith reflux
  2. waitAfter 12 h
  3. customto obtain a yellow precipitate which
  4. filtrationis filtered through fritted glass
  5. washwashed with ether
  6. custompurified on a flash column (support: silica; conditioning: heptane; eluant: dichloromethane/heptane, 60/40)
  7. customThe yellow powder obtained
  8. customafter evaporation of the solvent
  9. customrecrystallized in dichloromethane

Sources & evidence

ORD record
ord-02ec5a519ad14f02be13d55a4908bc37
Source dataset
uspto-grants-2001_07
Patent number
US06262095B1

Reaction notes

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