Hydrochloric Acid → 1-Benzofuran-5-carbaldehyde
Reaction equation
Br[C:2]1[CH:3]=[CH:4][C:5]2[O:9][CH:8]=[CH:7][C:6]=2[CH:10]=1.II.CN([CH:16]=[O:17])C.Cl>C1COCC1.O>[CH:16]([C:2]1[CH:3]=[CH:4][C:5]2[O:9][CH:8]=[CH:7][C:6]=2[CH:10]=1)=[O:17]Participants
Reactant 4
Product 1
Reagents, catalysts & solvents 2
Conditions
- Temperature
- -40 °C
Procedure
A mixture of 5-bromo-1-benzofuran (0.5 g), Mg (0.92 g, 0.038 mol), I2 (1 crystal) in dry THF (2.5 mL) under N2 atmosphere was refluxed for 30 min. To this was added a solution of 5-bromo-1-benzofuran (4.5 g) in 25 mL of dry THF) as soon as the 12 color disappear and refluxed for another 2 h. The reaction mixture was then cooled to −40° C. and added dry DMF (3.6 g) drop-wise and slowly warmed to RT for a period of 12 h. The reaction mixture was then cooled to 0° C. and acidified with 3N HCl to pH=2 and stirred for 30 min. The reaction mixture was then diluted with water (500 mL), extracted with ethylacetate (2×200 mL), washed with brine and dried. The solvent was removed under vacuum and purified by column chromatography over silica gel (pet. ether/CH2Cl2) to give 5-formyl-1-benzofuran (2 g, 54%) as a liquid. LC-MS: M/Z ESI: 1.47 min, 147.34 (M+1).
Workup
- temperaturewas refluxed for 30 min
- temperaturerefluxed for another 2 h
- temperatureslowly warmed to RT for a period of 12 h
- temperatureThe reaction mixture was then cooled to 0° C.
- extractionextracted with ethylacetate (2×200 mL)
- washwashed with brine
- customdried
- customThe solvent was removed under vacuum
- custompurified by column chromatography over silica gel (pet. ether/CH2Cl2)
Sources & evidence
- ORD record
- ord-036c255c7cb94c9589b0fddc31c7ebda
- Source dataset
- uspto-grants-2010_12
- Patent number
- US07846925B2
Reaction notes
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