2-methylcyclohexa-2,5-diene-1,4-dione

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

Procedure: Methyl-p-benzoquinone 12.2 g, 0.1 mole) and 2-mercaptoethanol (3.9 g, 0.05 mole) are mixed in absolute ethanol (70 ml) under nitrogen and with stirring. The temperature rises to 50° C. The mixture is cooled in a bath of ice-water and left to stand, with stirring, for 2 hours at ambient temperature. The solution is concentrated under vacuum and the oil obtained is chromatographed on Silica 60 (eluent: dichloromethane). According to 1H and 13C NMR, a first fraction (3 g) is a 50/50 mixture of two products: 2-hydroxyethylthio-5-methyl-1,4-benzoquinone and 2-hydroxyethylthio-6-methyl-1,4-benzoquinone. A second fraction gives the expected product: rises to 50° C left with stirring, for 2 hours at ambient temperature The solution is concentrated under vacuum the oil obtained is chromatographed on Silica 60 (eluent: dichloromethane) a 50/50 mixture of two products

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

Procedure: 2-methyl hydroquinone (1b) of 3.0 g (24 mmol) is dissolved in 150 ml of chloroform, wherein 100 ml each of hypochloride solution which have been so prepared as mentioned above are added and each reaction is made in the same way as described in Example 1, and then 2-methyl benzoquinone (IIb) is obtained. Table below shows the yields of isolation corresponding to each case of the investigation: above are added

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

Procedure: 2-methyl hydroquinone (1b) of 3.0 g (24 mmol) is dissolved in 150 ml of chloroform, wherein 100 ml each of hypochloride solution which have been so prepared as mentioned above are added and each reaction is made in the same way as described in Example 1, and then 2-methyl benzoquinone (IIb) is obtained. Table below shows the yields of isolation corresponding to each case of the investigation: above are added

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

Procedure: A mixture of m-cresol (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-methyl-1,4-benzoquinone formed (99%) was separated by chromatographic purification. was heated heated for 1 h The catalyst was recovered by simple filtration and 2-methyl-1,4-benzoquinone formed (99%) was separated by chromatographic purification

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

Procedure: A mixture of m-cresol (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-methyl-1,4-benzoquinone formed (99%) was separated by chromatographic purification. was heated heated for 1 h The catalyst was recovered by simple filtration and 2-methyl-1,4-benzoquinone formed (99%) was separated by chromatographic purification

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

Procedure: A mixture of o-cresol (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-methyl-1,4-benzoquinone formed (96%) was separated by chromatographic purification. was heated heated for 1 h The catalyst was recovered by simple filtration and 2-methyl-1,4-benzoquinone formed (96%) was separated by chromatographic purification

Conditions: temp:40.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Oxygen was passed into a solution of 0.68 g (2 mmol) of iron 5,14-dihydrodibenzo[b,i][5,9,14,18]tetraaza[14]annulene in 150 ml of 85% by weight aqueous acetic acid and, during this, a solution of 12.4 g (100 mmol) of methylhydroquinone and 0.5 g of concentrated sulfuric acid in 75 ml of 85% by weight acetic acid was added dropwise while stirring vigorously at 40° C. After oxygen up-take ceased, the mixture was subjected to a steam distillation. The distillate was extracted with tert-butyl methyl ether. The organic phase was shaken with aqueous sodium bicarbonate solution and then with water, separated from the aqueous phase, dried over magnesium sulfate, filtered and evaporated to dryness to yield 7.5 g (46%) of 2-methylbenzoquinone in the form of a yellow powder. Melting point 66°-68° C. the mixture was subjected to a steam distillation The distillate was extracted with tert-butyl methyl ether The organic phase was shaken with aqueous sodium bicarbonate solution with water, separated from the aqueous phase dried over magnesium sulfate filtered evaporated to dryness

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

Procedure: A solution of 12.4 g (100 mmol) of methylhydroquinone in 90 ml of acetic acid and 28.4 g (250 mmol) of 30% by weight aqueous hydrogen peroxide were simultaneously added dropwise to a stirred solution of 0.68 g (2.0 mmol) of iron 5,14-dihydrodibenzo[b,i]-[5,9,14,18]tetraaza[14]annulene, 2.52 g (2.0 mmol) of a 40% by weight aqueous solution of pentasodium diethylenetriaminepentaacetate and 0.5 ml of concentrated sulfuric acid in 50 ml of acetic acid at 40° C. with cooling. The mixture was then stirred for 15 min and subsequently subjected to a steam distillation. The distillate was extracted three times with a total of 400 ml of methylene chloride. The organic phase was shaken with aqueous sodium bicarbonate solution and then with water, separated from the aqueous phase, dried over magnesium sulfate, filtered and evaporated to dryness to yield 10.9 g (89%) of methylbenzoquinone in the form of a yellow powder. Melting point 69°-71° C. with cooling subsequently subjected to a steam distillation The distillate was extracted three times with a total of 400 ml of methylene chloride The organic phase was shaken with aqueous sodium bicarbonate solution with water, separated from the aqueous phase dried over magnesium sulfate filtered evaporated to dryness

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

Procedure: A solution of 12.4 g (100 mmol) of methylhydroquinone in 90 ml of acetic acid and 28.4 g (250 mmol) of 30% by weight aqueous hydrogen peroxide were simultaneously added dropwise to a stirred solution of 0.68 g (2.0 mmol) of iron 5,14-dihydrodibenzo[b,i]-[5,9,14,18]tetraaza[14]annulene, 2.52 g (2.0 mmol) of a 40% by weight aqueous solution of pentasodium diethylenetriaminepentaacetate and 0.5 ml of concentrated sulfuric acid in 50 ml of acetic acid at 40° C. with cooling. The mixture was then stirred for 15 min and subsequently subjected to a steam distillation. The distillate was extracted three times with a total of 400 ml of methylene chloride. The organic phase was shaken with aqueous sodium bicarbonate solution and then with water, separated from the aqueous phase, dried over magnesium sulfate, filtered and evaporated to dryness to yield 10.9 g (89%) of methylbenzoquinone in the form of a yellow powder. Melting point 69°-71° C. with cooling subsequently subjected to a steam distillation The distillate was extracted three times with a total of 400 ml of methylene chloride The organic phase was shaken with aqueous sodium bicarbonate solution with water, separated from the aqueous phase dried over magnesium sulfate filtered evaporated to dryness

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

Procedure: To a mixture of methyl-p-benzoquinone (60 g.), and hexachlorocyclopentadiene (140 g.), was added 20 ml. of toluene. This reaction mixture was then heated at 130°-140° C. for 3 hours. Upon cooling to room temperature the mixture solidified. This solid was washed with Skelly "B" solvent several times on a Buchner funnel and recrystallized from a Skelly "B"-benzene mixed solvent (20/80). Pale yellow crystals were obtained, m.p. 163°-165° C. was added 20 ml This reaction mixture was then heated at 130°-140° C. for 3 hours This solid was washed with Skelly "B" solvent several times on a Buchner funnel recrystallized from a Skelly "B"-benzene mixed solvent (20/80) Pale yellow crystals were obtained

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

Procedure: To a mixture of methyl-p-benzoquinone (60 g.), and hexachlorocyclopentadiene (140 g.), was added 20 ml. of toluene. This reaction mixture was then heated at 130°-140° C. for 3 hours. Upon cooling to room temperature the mixture solidified. This solid was washed with Skelly "B" solvent several times on a Buchner funnel and recrystallized from a Skelly "B"-benzene mixed solvent (20/80). Pale yellow crystals were obtained, m.p. 163°-165° C. was added 20 ml This reaction mixture was then heated at 130°-140° C. for 3 hours This solid was washed with Skelly "B" solvent several times on a Buchner funnel recrystallized from a Skelly "B"-benzene mixed solvent (20/80) Pale yellow crystals were obtained

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

Procedure: Methyl-p-benzoquinone 12.2 g, 0.1 mole) and 2-mercaptoethanol (3.9 g, 0.05 mole) are mixed in absolute ethanol (70 ml) under nitrogen and with stirring. The temperature rises to 50° C. The mixture is cooled in a bath of ice-water and left to stand, with stirring, for 2 hours at ambient temperature. The solution is concentrated under vacuum and the oil obtained is chromatographed on Silica 60 (eluent: dichloromethane). According to 1H and 13C NMR, a first fraction (3 g) is a 50/50 mixture of two products: 2-hydroxyethylthio-5-methyl-1,4-benzoquinone and 2-hydroxyethylthio-6-methyl-1,4-benzoquinone. A second fraction gives the expected product: rises to 50° C left with stirring, for 2 hours at ambient temperature The solution is concentrated under vacuum the oil obtained is chromatographed on Silica 60 (eluent: dichloromethane) a 50/50 mixture of two products