2-ethyl-4,6-dihydroxybenzaldehyde

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a mixture of 2-ethyl-4,6-dihydroxy-benzaldehyde (1 g, 6.02 mmol) in dichloromethane (50 mL) was added 3,4-dihydro-2H-pyran (1.1 mL, 12.05 mmol) and pyridium p-toluenesulfonic acid (0.010 g) at room temperature. The resulting mixture was stirred at room temperature for 16 hours then concentrated in vacuo. The residue was purified by silica gel flash column chromatography to give 2-ethyl-6-hydroxy-4-(tetrahydro-pyran-2-yloxy)-benzaldehyde (1.56 g, 100%). 1H NMR (400 MHz, CDCl3δ 12.40 (s, 1H), 10.08 (s, 1H), 6.48 (s, 1H), 6.40 (s, 1H), 5.50 (m, 1H), 3.84 (m, 1H), 3.60 (m, 1H), 2.90 (m, 2H), 2.00-1.50 (m, 6H), 1.30 (m, 3H). then concentrated in vacuo The residue was purified by silica gel flash column chromatography

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a suspension of 5-ethyl-benzene-1,3-diol (2.17 g, 15.72 mmol) and triethyl orthoformate (23.26 g, 157 mmol) in benzene (40 mL) was added AlCl3 (6.30 g, 47.16 mmol) at 0° C. The reaction mixture was stirred at room temperature for 30 minutes. After cooling to room temperature, the mixture was poured onto ice and acidified with HCl. The mixture was extracted with EtOAc and the organic extracts was dried over anhydrous MgSO4 and concentrated in vacuo. The residue was purified by silica gel flash column chromatography to give 2-ethyl-4,6-dihydroxy-benzaldehyde (1.0 g, 38%). 1H NMR (400 MHz, CDCl3δ 12.40 (s, 1H), 10.08 (s, 1H), 6.25 (s, 1H), 6.00 (s, 1H), 5.80 (s, 1H), 2.90 (m, 2H), 1.30 (m, 3H). After cooling to room temperature the mixture was poured onto ice The mixture was extracted with EtOAc the organic extracts was dried over anhydrous MgSO4 concentrated in vacuo The residue was purified by silica gel flash column chromatography