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

HRID 900782Notes

Reaction equation

HRID 900782 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-ed6602891a0142a685eec198d85498dd
Source dataset
uspto-grants-2008_04
Patent number
US07361670B2

Reaction notes

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