Cl.[CH3:2][C:3]1[C:4]([CH:13]=O)=[CH:5][C:6]2[CH2:10][CH2:9][O:8][C:7]=2[C:11]=1[CH3:12].C(O)(=O)C>[Zn].O>[CH3:13][C:4]1[C:3]([CH3:2])=[C:11]([CH3:12])[C:7]2[O:8][CH2:9][CH2:10][C:6]=2[CH:5]=1Zinc amalgum [prepared by heating a mixture of zinc dust (7.0 g), mercuric chloride (0.70 g), concentrated hydrochloric acid (0.5 ml) and water (30 ml) for 5 minutes and then decanting the aqueous solution] was added to a mixture of 2,3-dihydro-6,7-dimethylbenzo[b]furan-5-carboxaldehyde (6.93 g, 39 mmol), acetic acid (50 ml), water (50 ml), and concentrated hydrochloric acid (100 ml). The mixture was heated at reflux with vigorous stirring for 12 hours. After cooling, the mixture was poured into water. The dried (Na2SO4) ether extract was evaporated and the residue was purified by column chromatography over silica with hexane elution to give 2,3-dihydro-5,6,7-trimethylbenzo[b]furan (5.00 g, 78%) as a white solid, mp <50° C.
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