2,2-dimethyl-3H-1-benzofuran-3-ol

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

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

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 2,2-dimethyl-2,3-dihydro-benzofuran-3-ol (375 mg, 2.28 mmol) in THF (20 mL) is added methyl 4-imidazolecarboxylate (CAS#17325-26-7, 432 mg, 3.42 mmol), followed by triphenylphosphine (896 mg, 3.42 mmol). The reaction is cooled to 0° C. and di-t-butyl azodicarboxylate (787 mg, 3.42 mmol) is added. The reaction is permitted to warm to room temperature and stirred for 2 hours. The reaction mixture is then cooled to 0° C. and quenched with 4 N HCl in dioxane (5 mL, 20 mmol) and stirred for 30 minutes. The reaction is concentrated to near dryness and diluted with ethyl acetate. The organic layer is extracted three times with 1 N aqueous HCl. The aqueous extracts are combined, neutralized with Na2CO3, and extracted three times with ethyl acetate. The combined organic layers are dried with Na2SO4, filtered and concentrated. The resulting residue is purified by silica gel flash chromatography (ethyl acetate-dichloromethane, 0:1 to 1:5) to furnish 3-(2,2-dimethyl-2,3-dihydro-benzofuran-3-yl)-3H-imidazole-4-carboxylic acid methyl ester; HRMS: (ESI) m/z 245.0934 [(M+H)+: Calcd for C13H13N2O3: 245.0926]; 1H NMR (400 MHz, CDCl3) δ ppm 1.05 (s, 3H), 1.57 (s, 3 H), 3.92 (s, 3 H), 6.32 (s, 1 H), 6.92 (d, J=8.1 Hz, 1 H), 6.95-7.02 (m, 2 H), 7.25 (s, 1 H), 7.32-7.40 (m, 1 H), 7.80 (s, 1 H). to warm to room temperature The reaction mixture is then cooled to 0° C. stirred for 30 minutes The reaction is concentrated diluted with ethyl acetate The organic layer is extracted three times with 1 N aqueous HCl extracted three times with ethyl acetate The combined organic layers are dried with Na2SO4 filtered concentrated The resulting residue is purified by silica gel flash chromatography (ethyl acetate-dichloromethane, 0:1 to 1:5)

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

Procedure: To a solution of 2,2-dimethyl-benzofuran-3-one (1.58 g, 9.7 mmol) in methanol (30 mL) at 0° C. is added NaBH4 (0.36 g, 9.7 mmol). The reaction is placed at room temperature and another equivalent of NaBH4 (0.36 g, 9.7 mmol) is added. After three hours the reaction is quenched with saturated aqueous NH4Cl. The reaction is concentrated to approximately ¾ of its original volume, diluted with ethyl acetate, and washed with 2N aqueous HCl, followed by brine. The organic layer is dried with Na2SO4, filtered, and concentrated. The resulting residue is purified by silica gel flash chromatography (ethyl acetate-heptane, 0:1 to 1:8) to provide 2,2-dimethyl-2,3-dihydro-benzofuran-3-ol; 1H NMR (400 MHz, CDCl3) δ ppm 1.34 (s, 3 H), 1.49 (s, 3 H), 1.96 (d, J=8.6 Hz, 1 H), 4.71 (d, J=8.6 Hz, 1 H), 6.79 (d, J=8.1 Hz, 1 H), 6.87-6.95 (m, 1 H), 7.21-7.26 (m, 1 H), 7.39 (d, J=7.3 Hz, 1 H). is placed at room temperature After three hours the reaction is quenched with saturated aqueous NH4Cl The reaction is concentrated to approximately ¾ of its original volume diluted with ethyl acetate washed with 2N aqueous HCl The organic layer is dried with Na2SO4 filtered concentrated The resulting residue is purified by silica gel flash chromatography (ethyl acetate-heptane, 0:1 to 1:8)