Phosphorus tribromide → 4-Chloroisatoic anhydride

HRID 569806

Reaction equation

HRID 569806 reaction equation
C([O:8][C:9]([NH:11][C:12]1[CH:20]=[C:19]([Cl:21])[CH:18]=[CH:17][C:13]=1[C:14]([OH:16])=[O:15])=O)C1C=CC=CC=1.P(Br)(Br)Br>C(OCC)C>[Cl:21][C:19]1[CH:18]=[CH:17][C:13]2[C:14](=[O:16])[O:15][C:9](=[O:8])[NH:11][C:12]=2[CH:20]=1

Participants

4

Reactant 2

HCID 24614Phosphorus tribromideHCID 292998452-{[(Benzyloxy)carbonyl]amino}-4-chlorobenzoic acid

Product 1

HCID 3291054-Chloroisatoic anhydrideYield 91.9%

Reagents, catalysts & solvents 1

HCID 3283Diethyl EtherSolvent

Procedure

A mixture of 2-benzyloxycarbonylamino-4-chlorobenzoic acid (564 g) and phosphorus tribromide (1.5 kg) in diethyl ether (9 l) was refluxed for 40 hours and allowed to stand at room temperature for 5 days. The resulting precipitates were collected by filtration and washed in turn with diethyl ether (5 l) and ethanol (3 l) to give 7-chloro-2H-3,1-benzoxazine-2,4(1H)-dione (335 g).

Workup

  1. temperaturewas refluxed for 40 hours
  2. customThe resulting precipitates
  3. filtrationwere collected by filtration
  4. washwashed in turn with diethyl ether (5 l) and ethanol (3 l)

Sources & evidence

ORD record
ord-6dc96533fb65485b807fa9372d5d123a
Source dataset
uspto-grants-1988_03
Patent number
US04734419

Linked notes

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