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

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

Procedure: Little is known, however, concerning the reaction of methoxy and 2,6-dimethoxy-p-benzoquinone. (The latter can be generated from lignin). It has been shown that methoxy-p-benzoquinone will react with 1,3-butadiene to give 2-methoxy-4a,5,8,8a-tetrahydronapthoquinone [G. I. Birnbaum, J. Org. Chem., 25, 1660-1, (1960)]and with 2,3-dimethyl-1,3-butadiene to give 5,8-dihydro-2-methoxy-6,7-dimethyl -1,4-napthoquinone [M. F. Ansell, J. Chem. Soc., 3020, (1963)]. A more recent publication has shown that 2,6-dimethoxy-p-benzoquinone can be combined with isoprene to give a mixture of 2-methoxy-6-methyl-1,4-napthoquinone and 2-methoxy-7-methyl-1,4-napthoquinone [I.-M. TegmoLarsson, Tetra. Letters, 22, 2043-6, (1981)].

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

Procedure: To a suspension of 2-methoxy-p-benzoquinone (1.15 kg) (Step 1) in methanol (8 l) was added portionwise a suspension of 2-amino-5-methoxythiophenol (from Step 2) in methanol (6 l). The reacting mixture was stirred for 15 minutes, filtered and washed with methanol (8 l). The product isolated was swished with DMF (16 l) for 2 hours, filtered and air-dried. The crude material was dissolved in hot DMF (16 l) (130°-140° C.), filtered on Celite and the filtrate cooled to room temperature. The resulting crystals were filtered, washed with methanol (8 l) and air-dried to afford the title compound (70.3 g), m.p. 237°-238° C. was added portionwise filtered washed with methanol (8 l) The product isolated filtered air-dried The crude material was dissolved in hot DMF (16 l) (130°-140° C.) filtered on Celite The resulting crystals were filtered washed with methanol (8 l) air-dried

Conditions: temp:10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Vanillin (2.432 kg) was added to a solution of sodium hydroxide (640 g) in water (8 l) and cooled to 10° C. with an ice-bath. Then a solution of hydrogen peroxide (30%) (2.4 1) was added at a rate to keep the temperature of the reacting mixture below 30° C. The addition completed (about 2 hours), the reaction mixture was added over a period of 3 hours to a suspension of sodium periodate (880 g) in water (4 l) and acetic acid (640 ml) cooled with an ice-bath to 10° C. (the temperature of the reacting mixture was kept below 35° C.). The resulting precipitate was filtered, washed with cold water followed by ethanol/hexane (1:1) mixture and air-dried to afford the title compound (1.9 kg), m.p. 144°-147° C. the temperature of the reacting mixture below 30° C The addition (about 2 hours) cooled with an ice-bath to 10° C. (the temperature of the reacting mixture was kept below 35° C. The resulting precipitate was filtered washed with cold water air-dried

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

Procedure: To a suspension of 2-methoxy-p-benzoquinone, (1.15 kg) (Step 1) in methanol (8 l) was added portionwise a suspension of 2-amino-5-methoxythiophenol (from Step 2) in methanol (6 l). The reaction mixture was stirred for 15 minutes at room temperature, filtered and the collected solid washed with methanol (8 l). The product isolated was swished with DMF (16 l) for 2 hours, filtered and air-dried. The crude material was dissolved in hot DMF (16 l) (130°-140° C.), filtered through Celite and the filtrate cooled to room temperature. The crystals were filtered, washed with methanol (8 l) and air-dried to afford the title compound (703 g), m.p. 237°-238° C. was added portionwise filtered the collected solid washed with methanol (8 l) The product isolated filtered air-dried The crude material was dissolved in hot DMF (16 l) (130°-140° C.) filtered through Celite the filtrate cooled to room temperature The crystals were filtered washed with methanol (8 l) air-dried

Conditions: temp:10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Vanillin (2.432 kg) was added to a solution of sodium hydroxide (640 g) in water (8 l) and cooled to 10° C. with an ice-bath. Then a solution of hydrogen peroxide (30%) (2.4 l) was added at a rate to keep the temperature of the reaction mixture below 30° C. The addition completed (about 2 hours), the reaction mixture was added over a period of 3 hours to a suspension of sodium periodate (880 g) in water (4 l) and acetic acid (640 ml) cooled with an ice-bath to 10° C. (the temperature of the reaction mixture was kept below 35° C.). The precipitate was filtered, washed with cold water followed by ethanol/hexane (1:1) mixture and air-dried to afford the title compound (1.9 kg), m.p. 144°-147° C. the temperature of the reaction mixture below 30° C The addition (about 2 hours) cooled with an ice-bath to 10° C. (the temperature of the reaction mixture was kept below 35° C. The precipitate was filtered washed with cold water air-dried

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

Procedure: To a suspension of 2-methoxy-p-benzoquinone (1.15 kg) (Step 1) in methanol (8 l) was added portionwise a suspension of 2-amino-5-methoxythiophenol (from Step 2) in methanol (6 l). The reacting mixture was stirred for 15 minutes, filtered and washed with methanol (8 l). The product isolated was swished with DMF (16 l) for 2 hours, filtered and air-dried. The crude material was dissolved in hot DMF (16 l) (130°-140° C.), filtered on Celite and the filtrate cooled to room temperature. The resulting crystals were filtered, washed with methanol (8 l) and air-dried to afford the title compound (70.3 g), m.p. 237°-238° C. was added portionwise filtered washed with methanol (8 l) The product isolated filtered air-dried The crude material was dissolved in hot DMF (16 l) (130°-140° C.) filtered on Celite The resulting crystals were filtered washed with methanol (8 l) air-dried

Conditions: temp:10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Vanillin (2.432 kg) was added to a solution of sodium hydroxide (640 g) in water (8 l) and cooled to 10° C. with an ice-bath. Then a solution of hydrogen peroxide (30%) (2.4 l) was added at a rate to keep the temperature of the reacting mixture below 30° C. The addition completed (about 2 hours), the reaction mixture was added over a period of 3 hours to a suspension of sodium periodate (880 g) in water (4 l) and acetic acid (640 ml) cooled with an ice-bath to 10° C. (the temperature of the reacting mixture was kept below 35° C.). The resulting precipitate was filtered, washed with cold water followed by ethanol/hexane (1:1) mixture and air-dried to afford the title compound (1.9 kg), m.p. 144°-147° C. the temperature of the reacting mixture below 30° C The addition (about 2 hours) cooled with an ice-bath to 10° C. (the temperature of the reacting mixture was kept below 35° C. The resulting precipitate was filtered washed with cold water air-dried

Conditions: temp:210.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The same reactor as used in Example 7 was adopted. In this reactor, a solution of 120 g of maleic anhydride in 360 g of tetrahydronaphthalene was placed. Then, a solution of 220 g of dodecylamine and 1760 g of tetrahydronaphthalene was added thereto at 40° C. over a period of 120 minutes. After the addition was completed, the resultant mixture and 65.4 g of ortho-phosphoric acid (purity 89% by weight), 1.344 g of methoxybenzoquinone, and 0.1 g of zinc acetate added thereto were heated at 210° C. for one hour to effect reaction. Thereafter, the resultant reaction mixture was cooled to 30° C. and separated into a water layer and a tetrahydronaphthalene layer. The tetrahydronaphthalene layer was distilled to expel tetrahydronaphthalene. Consequently, there was obtained 285 g of slightly impure N-dodecyl maleimide. It was found to have purity of 92.3% by weight, indicating the yield thereof to be 83.5 mol % based on dodecylamine. After the addition reaction Thereafter, the resultant reaction mixture was cooled to 30° C. separated into a water layer The tetrahydronaphthalene layer was distilled

Conditions: temp:45.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Methoxy-p-benzoquinone (0.50 g) and 2,3-dimethyl-1,3-butadiene (0.63 ml) were added to 23.0 mL of glacial acetic acid. The mixture was heated at 45° C. for 18.5 hrs. A chromic acid solution consisting of 1.85 g of Na2Cr2O7.2H2O, 1.16 mL water, and 0.09 mL of concentrated H2SO4 was then added, and the temperature was kept at approximately 67° C. for 1 hour. The product was precipitated by the addition of ice water, washed several times with cold water, and then dried over P2O5. A 71% yield (0.557 g) of 2-methoxy-6,7-dimethyl-1,4-naphthoquinone was obtained. was then added The product was precipitated by the addition of ice water washed several times with cold water dried over P2O5

Conditions: temp:45.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Methoxy-p-benzoquinone (0.50 g) and 2,3-dimethyl-1,3-butadiene (0.63 ml) were added to 23.0 mL of glacial acetic acid. The mixture was heated at 45° C. for 18.5 hrs. A chromic acid solution consisting of 1.85 g of Na2Cr2O7.2H2O, 1.16 mL water, and 0.09 mL of concentrated H2SO4 was then added, and the temperature was kept at approximately 67° C. for 1 hour. The product was precipitated by the addition of ice water, washed several times with cold water, and then dried over P2O5. A 71% yield (0.557 g) of 2-methoxy-6,7-dimethyl-1,4-naphthoquinone was obtained. was then added The product was precipitated by the addition of ice water washed several times with cold water dried over P2O5

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

Procedure: Little is known, however, concerning the reaction of methoxy and 2,6-dimethoxy-p-benzoquinone. (The latter can be generated from lignin). It has been shown that methoxy-p-benzoquinone will react with 1,3-butadiene to give 2-methoxy-4a,5,8,8a -tetrahydronapthoquinone [G. I. Birnbaum, J. Org. Chem., 25, 1660-1, (1960)] and with 2,3-dimethyl-1,3-butadiene to give 5,8-dihydro-2-methoxy-6,7-dimethyl-1,4-napthoquinone [M. F. Ansell, J. Chem. Soc., 3020, (1963)]. A more recent publication has shown that 2,6-dimethoxy-p-benzoquinone can be combined with isoprene to give a mixture of 2-methoxy-6-methyl-1,4-napthoquinone and 2-methoxy-7-methyl-1,4-napthoquinone [I.-M. TegmoLarsson, Tetra. Letters, 22, 2043-6, (1981)].

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

Procedure: To a vigorously stirred solution of NaIO4 (33.5 g, 157 mmol, Baker) in H2O (1500 mL), there was added solid 2-methoxyhydroquinone (11.00 g, 50.0 mmol) in portions. The reaction immediately became dark orange. The reaction was allowed to stir for 1 h at rt and was extracted with CH2Cl2 (3×150 mL). The extract was washed with half saturated brine (1×150 mL), filtered through cotton and the solvent removed in vacuo to yield 2-methoxybenzoquinone as an orange solid (10.5 g) which was of sufficient purity (TLC analysis, 10% EtOAc/90% CHCl3) for further reaction. The crude quinone was combined with toluene (150 mL) and hydroquinone (1.0 g, Mallinkrodt). Neat 2,3-dimethyl-1,3-butadiene (8.3 g, 101 mmol, Aldrich) was added. The reaction was allowed to stir overnight at 65° C. under N2. TLC (10% EtOAc/90% CHCl3) indicated total consumption of the dienophile. The solvent was removed in vacuo to yield a dark solid. This was triturated with MeOH (100 mL) at n to give a beige solid. Crystallization from MeOH (dissolved in 140 mL, allowed to cool to rt) yielded a fluffy colorless solid (10.2 g, 64%, >95% pure by 1H NMR analysis); mp 133°-134° C. (MeOH); 1H NMR (CDCl3) δ1.62 (s, 6H), 2.12 (m, 2H), 2.42 (m, 2H), 3.09 (m, 1H), 3.20 (m, 1H), 3.78 (s, 3H), 5.88 (s, 1H). The reaction immediately became dark orange was extracted with CH2Cl2 (3×150 mL) The extract was washed with half saturated brine (1×150 mL) filtered through cotton the solvent removed in vacuo