Sulfuric Acid → HCID 15295001, compound

HRID 1647983Notes

Reaction equation

HRID 1647983 reaction equation
Br[CH2:2][CH2:3][CH2:4][CH2:5][CH2:6][O:7][C:8]1[CH:18]=[CH:17][C:11]2[C:12](=[O:16])[CH2:13][CH2:14][O:15][C:10]=2[C:9]=1[CH2:19][CH2:20][CH3:21].C([O:24][C:25]([C:27]1[O:28][C:29]2[C:35]([OH:36])=[CH:34][CH:33]=[CH:32][C:30]=2[CH:31]=1)=[O:26])C.C(=O)([O-])[O-].[K+].[K+].O.[OH-].[Li+].S(=O)(=O)(O)O>C1COCC1.O.C(OCC)(=O)C.CCOCC.CC(=O)CC>[O:16]=[C:12]1[C:11]2[CH:17]=[CH:18][C:8]([O:7][CH2:6][CH2:5][CH2:4][CH2:3][CH2:2][O:36][C:35]3[C:29]4[O:28][C:27]([C:25]([OH:26])=[O:24])=[CH:31][C:30]=4[CH:32]=[CH:33][CH:34]=3)=[C:9]([CH2:19][CH2:20][CH3:21])[C:10]=2[O:15][CH2:14][CH2:13]1

Participants

11

Reactant 5

HCID 1118Sulfuric AcidHCID 11430Potassium CarbonateHCID 168937Lithium hydroxide, monohydrateHCID 19921918HCID 19921918, compoundHCID 21400703Ethyl 7-hydroxy-1-benzofuran-2-carboxylate

Product 1

HCID 15295001HCID 15295001, compoundYield 74.9%

Reagents, catalysts & solvents 5

HCID 962WaterSolventHCID 3283Diethyl EtherSolventHCID 6569Methyl Ethyl KetoneSolventHCID 8028TetrahydrofuranSolventHCID 8857Ethyl AcetateSolvent

Procedure

A mixture of 0.556 g (1.57 mmol) of 7-[(5-bromopentyl)oxy]-2,3-dihydro-8-propyl-4H-1-benzopyran-4-one, 0.323 g (1.57 mmol) of 7-hydroxy-2-benzofurancarboxylic acid ethyl ester, 0.866 g (6.26 mmol) of anhydrous granular potassium carbonate and 16 mL of 2-butanone was stirred and refluxed for 16.5 hrs. The resulting slurry was filtered with suction and the solids were washed thoroughly with ethyl acetate. The filtrate and washes were combined and concentrated in vacuo and the residue was purified by flash chromatography on 70 g of silica gel, eluting with 4:1 hexane-ethyl acetate giving 0.527 g (70%) of 7-[5-[(3,4-dihydro-4-oxo-8-propyl-2H-1-benzopyran-7-yl)oxy]pentyloxy]-2-benzofurancarboxylic acid ethyl ester as a white solid, mp 79.5°-81° C. A mixture of 0.262 g (0.55 mmol) of this ester in 3.5 mL of THF and 3.5 mL of water was treated with 35.1 mg (0.84 mmol) of lithium hydroxide monohydrate and the mixture was stirred for 17.5 hr. After being acidified with 16 mL of 3N aqueous sulfuric acid, the resulting mixture was worked-up with ether and ethyl acetate in the usual manner. The crude product was recrystallized from hexane-ethyl acetate to give 0.185 g (74.9%) of the title compound as a white solid, mp 152°-153.5° C.

Workup

  1. temperaturerefluxed for 16.5 hrs
  2. filtrationThe resulting slurry was filtered with suction
  3. washthe solids were washed thoroughly with ethyl acetate
  4. concentrationconcentrated in vacuo
  5. customthe residue was purified by flash chromatography on 70 g of silica gel
  6. washeluting with 4:1 hexane-ethyl acetate giving 0.527 g (70%) of 7-[5-[(3,4-dihydro-4-oxo-8-propyl-2H-1-benzopyran-7-yl)oxy]pentyloxy]-2-benzofurancarboxylic acid ethyl ester as a white solid, mp 79.5°-81° C
  7. stirringthe mixture was stirred for 17.5 hr
  8. customThe crude product was recrystallized from hexane-ethyl acetate

Sources & evidence

ORD record
ord-9c33b070402d46a394ce33df96b5f2a3
Source dataset
uspto-grants-1995_07
Patent number
US05434186

Reaction notes

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