Phosgene → Ethyl 3h-furo[2,3-f]benzoxazole-2-one-6-carboxylate

HRID 902132Notes

Reaction equation

HRID 902132 reaction equation
[OH:1][C:2]1[C:3]([NH2:16])=[CH:4][C:5]2[O:9][C:8]([C:10]([O:12][CH2:13][CH3:14])=[O:11])=[CH:7][C:6]=2[CH:15]=1.[O:17]1CCC[CH2:18]1.C(Cl)(Cl)=O>C1(C)C=CC=CC=1.C(N(CC)CC)C>[O:1]1[C:2]2[CH:15]=[C:6]3[CH:7]=[C:8]([C:10]([O:12][CH2:13][CH3:14])=[O:11])[O:9][C:5]3=[CH:4][C:3]=2[NH:16][C:18]1=[O:17]

Participants

6

Reactant 3

HCID 6371PhosgeneHCID 8028TetrahydrofuranHCID 22350189Ethyl 5-hydroxy-6-aminobenzofuran-2-carboxylate

Product 1

HCID 22350166Ethyl 3h-furo[2,3-f]benzoxazole-2-one-6-carboxylateYield 96%

Reagents, catalysts & solvents 2

HCID 1140TolueneSolventHCID 8471TriethylamineSolvent

Procedure

A mixture of 0.9 g (4.2 mmol) of ethyl 5-hydroxy-6-aminobenzofuran-2-carboxylate [Helv. Chim. Acta 77, 100. (1994)], 60 ml of tetrahydrofuran, 3.1 ml of 20% phosgene in toluene solution and 2.0 ml of triethylamine is stirred at room temperature for 1 h. The tetrahydrofuran is distilled off in vacuum, water is added to the residue and the product is extracted with ethyl acetate. The combined organic layers are washed with 5% aqueous sodium hydrogencarbonate solution, water, 1 N hydrochloric acid solution and again with water, dried over sodium sulfate and concentrated to yield 1.0 g (96%) of the title compound as oil.

Workup

  1. distillationThe tetrahydrofuran is distilled off in vacuum, water
  2. additionis added to the residue
  3. extractionthe product is extracted with ethyl acetate
  4. washThe combined organic layers are washed with 5% aqueous sodium hydrogencarbonate solution, water, 1 N hydrochloric acid solution and again with water
  5. dry with materialdried over sodium sulfate
  6. concentrationconcentrated

Sources & evidence

ORD record
ord-a7b5a437c4314b759446f7ce7cb3ba52
Source dataset
uspto-grants-2008_04
Patent number
US07365083B2

Reaction notes

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