Pyridinium chloride → 7-(4-Hydroxyphenyl)-benzofuran-5-carbaldehyde

HRID 1372168Notes

Reaction equation

C[O:2][C:3]1[CH:8]=[CH:7][C:6]([C:9]2[C:17]3[O:16][CH:15]=[CH:14][C:13]=3[CH:12]=[C:11]([CH:18]=[O:19])[CH:10]=2)=[CH:5][CH:4]=1.Cl.N1C=CC=CC=1>O>[OH:2][C:3]1[CH:8]=[CH:7][C:6]([C:9]2[C:17]3[O:16][CH:15]=[CH:14][C:13]=3[CH:12]=[C:11]([CH:18]=[O:19])[CH:10]=2)=[CH:5][CH:4]=1

Participants

Conditions

Temperature: 190 °C

Procedure

To a 10 ml round bottom flask was added 7-(4-methoxyphenyl)-benzofuran-5-carbaldehyde (0.50 g, 1.98 mmol), and pyridine hydrochloride (1.2 g, 5.2 mmol). The mixture was heated to 190° C. for 2 h, cooled slightly, then water (10 ml) was added to dissolve the remaining pyridine hydrochloride. The aqueous was extracted with EtOAc (3×), passed through a silica plug, and concentrated to 450 mg (96%) of crude product as a light yellow foam. The crude from this reaction was combined with a second batch (1 g scale reaction) and purified by column chromatography (1:1 EtOAc/Hexanes) to afford 760 mg of product as a yellow solid: mp 154–155° C.; 1H NMR (300 MHz, DMSO-d6): δ 6.95 (2H, d, J=8.6 Hz), 7.21 (1H, d, J=2.2 Hz), 7.76 (2H, d, J=8.6 Hz), 7.98 (1H, d, J=1.5 Hz), 8.19 (1H, d, J=1.5 Hz), 8.22 (1H, d, J=2.2 Hz), 9.81 (1H, s), 10.12 (1H, s); MS (ESI) m/z 237 ([M−H]−).

Workup

temperaturecooled slightly
extractionThe aqueous was extracted with EtOAc (3×)
concentrationconcentrated to 450 mg (96%) of crude product as a light yellow foam
customThe crude from this reaction was combined with a second batch (1 g scale reaction)
custompurified by column chromatography (1:1 EtOAc/Hexanes)

Sources & evidence

ORD record: ord-d3c68c82fcff41c38369a5e75db77d0b
Source dataset: uspto-grants-2007_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07157491B2

Reaction notes

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