2,6-dimethylcyclohexa-2,5-diene-1,4-dione

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

Procedure: Under nitrogen atmosphere, 6 mL of. THF was added to 1.22 g (2 mmol, 0.6 equivalent) of (BrZnCH2COOEt.THF)2. Under argon atmosphere, a solution of 0.45 g (3.33 mmol) of 2,6-dimethyl-p-benzoquinone in 3 mL of THF was added dropwise while stirring at 0˜5° C. The mixture was stirred at 20˜25° C. for 1 hour. 5 mL of 1N hydrochloric acid was added dropwise at 20° C. or lower, followed by dilution with 25 mL of ethyl acetate. Then, the layers were separated. The organic layer was washed successively with 5 mL (×2) of 1N hydrochloric acid, 5 mL of water, 10 mL (×2) of an aqueous saturated sodium bicarbonate solution, and 5 mL (×2) of an aqueous saturated sodium chloride solution. After washing, the organic layer was dried with anhydrous magnesium sulfate. After concentration under reduced pressure, purification with silica gel column (developing solvent; ethyl acetate/n-hexane=1/3) afforded 0.60 g of the desired product (yield 80%). The mixture was stirred at 20˜25° C. for 1 hour Then, the layers were separated The organic layer was washed successively with 5 mL (×2) of 1N hydrochloric acid, 5 mL of water, 10 mL (×2) of an aqueous saturated sodium bicarbonate solution, and 5 mL (×2) of an aqueous saturated sodium chloride solution After washing the organic layer was dried with anhydrous magnesium sulfate After concentration under reduced pressure, purification with silica gel column (developing solvent; ethyl acetate/n-hexane=1/3)

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

Procedure: A solution of 2,6-dimethyl-1,4-benzoquinone (Xa) (5.66 g, 42 mmol, Aldrich) in Et2O (200 mL) was shaken vigorously in a separatory funnel with two 200 mL portions of aqueous sodium hydrosulfite solution (sodium dithionite, Na2S2O4, 14.5 g, 83.3 mmol) until the Et2O layer turned bright yellow. The ether layer was washed with brine (200 mL×2), dried (MgSO4) and concentrated in vacuo to obtain 4.865 g (35.3 mmol, Y: 83.9%) of the title compound as a white solid; mp, 148-150° C. (acetone-hexane) [mp reported by L. A. Carpino, S. A. Triolo, and R. A. Berglund in J. Org. Chem., 54, p. 3303 (1989): 145-148° C.]; Rf: 0.47 (10% EtOAc in CH2Cl2); IR(KBr) 3312 cm-1 (OH); 1H-NMR (300 MHz, acetone-d6) δ ppm: 2.15 (6H, s, Me), 6.45 (2H, s, Ar-H), 6.58 (1H, s, OH), 7.47 (1H, s, OH); 13C-NMR (75 MHz, acetone-d6) δ ppm: 16.84, 116.00, 126.45, 147.46, 151.54; MS (isobutane-DCI) m/e: 139 (MH+). The ether layer was washed with brine (200 mL×2) dried (MgSO4) concentrated in vacuo

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

Procedure: To a cooled (0° C.), stirred mixture of 4-chloro-phenol (4.34 g) and 2,6-dimethylbenzoquinone (4.60 g) was added dropwise a solution of (2-methyl-pent-4-en-2-oxy)diphenylphosphine (8.0 g) in dichloroethane (20 ml). The mixture was then heated at 95° C. for 24 h. The reaction mixture was cooled to room temperature and concentrated in vacuo and the residue was purified by column chromatography (SiO2; gradient: heptane/EtOAc) to give 1-chloro-4-(1,1-dimethyl-but-3-enyloxy)-benzene (0.14 g, 2%) as a colourless oil. MS (EI): 171.1 ([{37Cl}M-C3H5]+), 1691 ([{35Cl}M-C3H5]+). The mixture was then heated at 95° C. for 24 h The reaction mixture was cooled to room temperature concentrated in vacuo the residue was purified by column chromatography (SiO2; gradient: heptane/EtOAc)

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

Procedure: To a cooled (0° C.), stirred mixture of 4-chloro-phenol (4.34 g) and 2,6-dimethylbenzoquinone (4.60 g) was added dropwise a solution of (2-methyl-pent-4-en-2-oxy)diphenylphosphine (8.0 g) in dichloroethane (20 ml). The mixture was then heated at 95° C. for 24 h. The reaction mixture was cooled to room temperature and concentrated in vacuo and the residue was purified by column chromatography (SiO2; gradient: heptane/EtOAc) to give 1-chloro-4-(1,1-dimethyl-but-3-enyloxy)-benzene (0.14 g, 2%) as a colourless oil. MS (EI): 171.1 ([{37Cl}M-C3H5]+), 1691 ([{35Cl}M-C3H5]+). The mixture was then heated at 95° C. for 24 h The reaction mixture was cooled to room temperature concentrated in vacuo the residue was purified by column chromatography (SiO2; gradient: heptane/EtOAc)

Conditions: temp:55.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 2,6-dimethylphenol (5 mmol) and Ti-superoxide catalyst (125 mg, 20% w/w) in acetic acid (5 ml) was heated with stirring at 50-60° C. under inert atmosphere. To this reaction mixture was added aq. 30% H2O2 (20 mmol) drop wise over 15 min. and heated for 1 h. The catalyst was recovered by simple filtration and 2,6-dimethyl-1,4-benzoquinone formed (97%) was separated by chromatographic purification. was heated heated for 1 h The catalyst was recovered by simple filtration and 2,6-dimethyl-1,4-benzoquinone formed (97%) was separated by chromatographic purification

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

Procedure: To a cooled (0° C.), stirred mixture of 4-chloro-phenol (4.34 g) and 2,6-dimethylbenzoquinone (4.60 g) was added dropwise a solution of (2-methyl-pent-4-en-2-oxy)diphenylphosphine (8.0 g) in dichloroethane (20 ml). The mixture was then heated at 95° C. for 24 h. The reaction mixture was cooled to room temperature and concentrated in vacuo and the residue was purified by column chromatography (SiO2; gradient: heptane/EtOAc) to give 1-chloro-4-(1,1-dimethyl-but-3-enyloxy)-benzene (0.14 g, 2%) as a colourless oil. MS (EI): 171.1 ([{37Cl}M−C3H5−]+), 1691 ([{35Cl}M−C3H5]+). The mixture was then heated at 95° C. for 24 h The reaction mixture was cooled to room temperature concentrated in vacuo the residue was purified by column chromatography (SiO2; gradient: heptane/EtOAc)

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

Procedure: To a cooled (0° C.), stirred mixture of 4-chloro-phenol (4.34 g) and 2,6-dimethylbenzoquinone (4.60 g) was added dropwise a solution of (2-methyl-pent-4-en-2-oxy)diphenylphosphine (8.0 g) in dichloroethane (20 ml). The mixture was then heated at 95° C. for 24 h. The reaction mixture was cooled to room temperature and concentrated in vacuo and the residue was purified by column chromatography (SiO2; gradient: heptane/EtOAc) to give 1-chloro-4-(1,1-dimethyl-but-3-enyloxy)-benzene (0.14 g, 2%) as a colourless oil. MS (EI): 171.1 ([{37Cl}M−C3H5−]+), 1691 ([{35Cl}M−C3H5]+). The mixture was then heated at 95° C. for 24 h The reaction mixture was cooled to room temperature concentrated in vacuo the residue was purified by column chromatography (SiO2; gradient: heptane/EtOAc)

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

Procedure: Under nitrogen atmosphere, 6 mL of. THF was added to 1.22 g (2 mmol, 0.6 equivalent) of (BrZnCH2COOEt.THF)2. Under argon atmosphere, a solution of 0.45 g (3.33 mmol) of 2,6-dimethyl-p-benzoquinone in 3 mL of THF was added dropwise while stirring at 0˜5° C. The mixture was stirred at 20˜25° C. for 1 hour. 5 mL of 1N hydrochloric acid was added dropwise at 20° C. or lower, followed by dilution with 25 mL of ethyl acetate. Then, the layers were separated. The organic layer was washed successively with 5 mL (×2) of 1N hydrochloric acid, 5 mL of water, 10 mL (×2) of an aqueous saturated sodium bicarbonate solution, and 5 mL (×2) of an aqueous saturated sodium chloride solution. After washing, the organic layer was dried with anhydrous magnesium sulfate. After concentration under reduced pressure, purification with silica gel column (developing solvent; ethyl acetate/n-hexane=1/3) afforded 0.60 g of the desired product (yield 80%). The mixture was stirred at 20˜25° C. for 1 hour Then, the layers were separated The organic layer was washed successively with 5 mL (×2) of 1N hydrochloric acid, 5 mL of water, 10 mL (×2) of an aqueous saturated sodium bicarbonate solution, and 5 mL (×2) of an aqueous saturated sodium chloride solution After washing the organic layer was dried with anhydrous magnesium sulfate After concentration under reduced pressure, purification with silica gel column (developing solvent; ethyl acetate/n-hexane=1/3)

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

Procedure: A solution of 2,6-dimethyl-1,4-benzoquinone (Xa) (5.66 g, 42 mmol, Aldrich) in Et2O (200 mL) was shaken vigorously in a separatory funnel with two 200 mL portions of aqueous sodium hydrosulfite solution (sodium dithionite, Na2S2O4, 14.5 g, 83.3 mmol) until the Et2O layer turned bright yellow. The ether layer was washed with brine (200 mL×2), dried (MgSO4) and concentrated in vacuo to obtain 4.865 g (35.3 mmol, Y: 83.9%) of the title compound as a white solid; mp, 148-150° C. (acetone-hexane) [mp reported by L. A. Carpino, S. A. Triolo, and R. A. Berglund in J. Org. Chem., 54, p. 3303 (1989): 145-148° C.]; Rf: 0.47 (10% EtOAc in CH2Cl2); IR(KBr) 3312 cm-1 (OH); 1H-NMR (300 MHz, acetone-d6) δ ppm: 2.15 (6H, s, Me), 6.45 (2H, s, Ar-H), 6.58 (1H, s, OH), 7.47 (1H, s, OH); 13C-NMR (75 MHz, acetone-d6) δ ppm: 16.84, 116.00, 126.45, 147.46, 151.54; MS (isobutane-DCI) m/e: 139 (MH+). The ether layer was washed with brine (200 mL×2) dried (MgSO4) concentrated in vacuo

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

Procedure: A solution of 2,6-dimethyl-1,4-benzoquinone (Xa) (5.66 g, 42 mmol, Aldrich) in Et2O (200 mL) was shaken vigorously in a separatory funnel with two 200 mL portions of aqueous sodium hydrosulfite solution (sodium dithionite, Na2S2O4, 14.5 g, 83.3 mmol) until the Et2O layer turned bright yellow. The ether layer was washed with brine (200 mL×2), dried (MgSO4) and concentrated in vacuo to obtain 4.865 g (35.3 mmol, Y: 83.9%) of the title compound as a white solid; mp, 148-150° C. (acetone-hexane) [mp reported by L. A. Carpino, S. A. Triolo, and R. A. Berglund in J. Org. Chem., 54, p. 3303 (1989): 145-148° C.]; Rf: 0.47 (10% EtOAc in CH2Cl2); IR(KBr) 3312 cm-1 (OH); 1H-NMR (300 MHz, acetone-d6) δ ppm: 2.15 (6H, s, Me), 6.45 (2H, s, Ar-H), 6.58 (1H, s, OH), 7.47 (1H, s, OH); 13C-NMR (75 MHz, acetone-d6) δ ppm: 16.84, 116.00, 126.45, 147.46, 151.54; MS (isobutane-DCI) m/e: 139 (MH+). The ether layer was washed with brine (200 mL×2) dried (MgSO4) concentrated in vacuo

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

Procedure: A solution of 2,6-dimethyl-1,4-benzoquinone (Xa) (5.66g, 42 mmol, Aldrich) in Et2O (200 mL) was shaken vigorously in a separatory funnel with two 200 mL portions of aqueous sodium hydrosulfite solution (sodium dithionite, Na2S2O4, 14.5 g, 83.3 mmol) until the Et2O layer turned bright yellow. The ether layer was washed with brine (200 mL×2), dried (MgSO4) and concentrated in vacuo to obtain 4.865g (35.3 mmol, Y: 83.9%) of the title compound as a white solid: mp, 148°-150° C. (acetone-hexane) [mp reported by L. A. Carpino, S. A. Triolo, and R. A. Berglund in J. Org. Chem., 54, 3303 (1989): 145°-148° C.]; Rf 0.47 (10% EtOAc in CH2Cl2); IR(KBr) 3312 cm-1 (OH); 1H-NMR (300 MHz, acetone-d6) δ ppm: 2.15 (6H, s, Me), 6.45 (2H, s, Ar-H), 6.58 (1H, s, OH), 7.47 (1H, s, OH); 13C-NMR (75 MHz, acetone-d6) δ ppm: 16.84, 116.00, 126.45, 147.46, 151.54; MS (isobutane-DCI) m/e 139 (MH+). The ether layer was washed with brine (200 mL×2) dried (MgSO4) concentrated in vacuo

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

Procedure: A solution of 2,6-dimethyl-1,4-benzoquinone (Xa) (5.66g, 42 mmol, Aldrich) in Et2O (200 mL) was shaken vigorously in a separatory funnel with two 200 mL portions of aqueous sodium hydrosulfite solution (sodium dithionite, Na2S2O4, 14.5 g, 83.3 mmol) until the Et2O layer turned bright yellow. The ether layer was washed with brine (200 mL×2), dried (MgSO4) and concentrated in vacuo to obtain 4.865g (35.3 mmol, Y: 83.9%) of the title compound as a white solid: mp, 148°-150° C. (acetone-hexane) [mp reported by L. A. Carpino, S. A. Triolo, and R. A. Berglund in J. Org. Chem., 54, 3303 (1989): 145°-148° C.]; Rf 0.47 (10% EtOAc in CH2Cl2); IR(KBr) 3312 cm-1 (OH); 1H-NMR (300 MHz, acetone-d6) δ ppm: 2.15 (6H, s, Me), 6.45 (2H, s, Ar-H), 6.58 (1H, s, OH), 7.47 (1H, s, OH); 13C-NMR (75 MHz, acetone-d6) δ ppm: 16.84, 116.00, 126.45, 147.46, 151.54; MS (isobutane-DCI) m/e 139 (MH+). The ether layer was washed with brine (200 mL×2) dried (MgSO4) concentrated in vacuo