Hydrochloric Acid → 3-Methyl-4-hydroxy-7-(2-thienoyl)benzofuran

HRID 1084857Notes

Reaction equation

HRID 1084857 reaction equation
Cl.[NH+]1C=CC=CC=1.[CH3:8][C:9]1[C:13]2[C:14]([O:25]C)=[CH:15][CH:16]=[C:17]([C:18]([C:20]3[S:21][CH:22]=[CH:23][CH:24]=3)=[O:19])[C:12]=2[O:11][CH:10]=1.O.Cl>N1C2C(=CC=CC=2)C=CC=1>[CH3:8][C:9]1[C:13]2[C:14]([OH:25])=[CH:15][CH:16]=[C:17]([C:18]([C:20]3[S:21][CH:22]=[CH:23][CH:24]=3)=[O:19])[C:12]=2[O:11][CH:10]=1

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 962WaterHCID 151240023-Methyl-4-methoxy-7-(2-thienoyl)benzofuranHCID 21584435Pyridinium hydrochloride2×

Product 1

HCID 151240033-Methyl-4-hydroxy-7-(2-thienoyl)benzofuran

Reagents, catalysts & solvents 1

HCID 7047QuinolineSolvent

Procedure

A solution of freshly prepared pyridinium hydrochloride (4.84 g, 41.9 mmol) and 3-methyl-4-methoxy-7-(2-thienoyl)benzofuran (2.30 g, 8.38 mmol) in quinoline (10 mL) was heated to reflux for 2.5 hours. The mixture was cooled, an additional portion of pyridinium hydrochloride added (2.42 g, 20.9 mmol) and reflux was resumed for one hour. After cooling the reaction mixture was poured into water (200 mL) and acidified with 2N HCl. The resulting mixture was extracted with chloroform (5×50 mL) and the combined organic extracts were washed with water (50 mL), dried (Na2SO4), and concentrated. Chromatographic purification by preparative HPLC using 25% ethyl acetate in hexane as eluant afforded 3-methyl-4-hydroxy-7-(2-thienoyl)benzofuran compound 3 along with recovered starting material. A sample of the desired product was recrystallized from ether/hexane. 1H NMR d 2.45 (3H, s), 6.24 (1H, br s), 6.45 (1H, d, J=8 Hz), 7.17 (1H, dd, J=4 Hz, 4 Hz), 7.37 (1H, s), 7.61 (1H, d, J=8 Hz), 7.67 (1H, d, J=4 Hz), 7.75 (1H, d, J=4 Hz).

Workup

  1. temperatureto reflux for 2.5 hours
  2. temperatureThe mixture was cooled
  3. temperaturereflux
  4. temperatureAfter cooling the reaction mixture
  5. extractionThe resulting mixture was extracted with chloroform (5×50 mL)
  6. washthe combined organic extracts were washed with water (50 mL)
  7. dry with materialdried (Na2SO4)
  8. concentrationconcentrated
  9. customChromatographic purification by preparative HPLC

Sources & evidence

ORD record
ord-b55f8bdaa5ce4229b030919dee84145a
Source dataset
uspto-grants-1991_04
Patent number
US05006549

Reaction notes

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