(±)-1-(2-呋喃基)乙醇

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: Ten grams of the distilled 1-furylethanol (0.089 mole) is charged to a reactor with 0.61 g (2 mole percent) tetrabutylammonium bisulfate and 19.2 g of a 50 percent aqueous solution of sodium hydroxide added over a 15 minute period with stirring. This is followed by addition of 34.7 g (0.25 mole) 1-bromopentane over a period of 15 minutes and the reaction mixture allowed to stir for 3 hours. The reaction mixture is then extracted with diethyl ether which, after drying over magnesium sulfate, is evaporated. The resulting crude product is short-path distilled to obtain 2-(1-pentoxyethyl)furan in low yield (B.p. 35° C. at 0.2 mm Hg.). The structure of the 2-(1-pentoxyethyl)furan ##STR5## is confirmed by infrared and nuclear magnetic resonance spectroscopy. added over a 15 minute period to stir for 3 hours The reaction mixture is then extracted with diethyl ether which after drying over magnesium sulfate is evaporated The resulting crude product is short-path distilled

反应条件: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a 3-neck round bottom flask is charged a solution of 50 ml of water and 20 ml of tetrahydrofuran and the solution is cooled to 0° C. An addition funnel is charged with a solution of 1(2-furyl)-1-ethanol (0.89 mole) in 25 ml of tetrahydrofuran and this solution is added dropwise to the reaction flask while BrCl (0.30 mole) is added via a gas inlet tube. The rate of addition is such that all the furfuryl alcohol is added in the first 1.3-1.5 equivalents of BrCl while maintaining the temperature below 30° C. The reaction mixture is heated to reflux and the tetrahydrofuran removed by distillation. When the temperature reaches 105° C., a condensor is attached and the reaction mixture heated under reflux for about 2 hours. The reaction mixture is cooled and maltol isolated by the method of Example 1. is added via a gas inlet tube The rate of addition while maintaining the temperature below 30° C The reaction mixture is heated to reflux the tetrahydrofuran removed by distillation reaches 105° C. the reaction mixture heated under reflux for about 2 hours The reaction mixture is cooled

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a solution of 1(2-furyl)-1-ethanol (0.05 mole) in 15 ml of tetrahydrofuran and 15 ml of water at 5° C. is added 21.7 ml of 2.8 M sodium hypochlorite solution. Chlorine (0.05 mole) is added to the reaction flask via a gas inlet tube maintaining the reaction temperature below 5° C. The reaction mixture is then heated to reflux and the tetrahydrofuran removed by distillation. Heating is continued for an additional hour. The reaction mixture is cooled and maltol is isolated by the procedure described in Example 1. maintaining the reaction temperature below 5° C The reaction mixture is then heated to reflux the tetrahydrofuran removed by distillation Heating is continued for an additional hour The reaction mixture is cooled

反应条件: temp:10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a 4-neck round bottom flask equipped with a thermometer, a condensor and two addition funnels was charged 50 ml of tetrahydrofuran and 50 ml of water and the solution was cooled to 10° C. To this well stirred solution was added together in the two addition funnels bromine (0.20 mole) and 1(2-furyl)-1-ethanol (0.09 mole). The temperature of the reaction was maintained at 15° C. throughout the double addition. The reaction mixture was then heated to 75° C. for 10 hours. Maltol was isolated by the procedure of Example 1 (53% yield). To a 4-neck round bottom flask equipped with a thermometer a condensor and two addition funnels The temperature of the reaction was maintained at 15° C. throughout the double addition The reaction mixture was then heated to 75° C. for 10 hours

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: In a 3-neck round bottom flask equipped with a stirring bar, a gas inlet tube and an addition funnel was added 20 ml of tetrahydrofuran, 50 ml of water and sodium bromide (0.20 mole). The solution was cooled to a temperature of 0° to 20° C. The addition funnel was charged with a solution of 1(2-furyl)-1-ethanol (0.18 mole) in 20 ml of tetrahydrofuran and this was added dropwise to the rapidly stirred reaction flask while gaseous chlorine (0.40 mole) is added via the gaseous inlet tube. The rate of the alcohol addition was such that a yellow orange color was maintained. The reaction temperature was kept below 20° C. with ice bath cooling. After the alcohol and chlorine had both been added to the reaction flask, the temperature was raised to reflux to distill off the tetrahydrofuran. The isolation procedure of Example 1 was used to isolate 12.47 g of pure maltol (55% yield). In a 3-neck round bottom flask equipped with a stirring bar, a gas inlet tube and an addition funnel The solution was cooled to a temperature of 0° to 20° C is added via the gaseous inlet tube was maintained The reaction temperature was kept below 20° C. with ice bath cooling both been added to the reaction flask the temperature was raised to reflux to distill off the tetrahydrofuran

反应条件: temp:5.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: In a 3-neck round bottom flask equipped with a magnetic stirring bar, a gas inlet tube, a thermometer and an addition funnel was added 20 ml of tetrahydrofuran and 50 ml of water. The solution was cooled to a temperature of 0° to 10° C. The addition funnel was charged with a solution of 1(2-furyl)-1-ethanol (0.089 moles) in 20 ml of tetrahydrofuran and this was added dropwise to the stirred reaction flask while chlorine (0.30 mole) was added via the gas inlet tube. The rate of addition was such that all the alcohol was added in the first 1.3-1.5 equivalents of chlorine (approximately 30 minutes) while maintaining the reaction temperature below 10° C. The reaction mixture was heated to reflux and the tetrahydrofuran removed by distillation. When the reaction mixture reached a temperature of about 105° C., a condenser was added and the refluxing continued for about 2 hours. The reaction mixture was then filtered hot, cooled, the pH adjusted to 2.2 and the reaction mixture was cooled to 5° C. Crystallization and filtration yielded 3.43 grams of crude 3-hydroxy-2-methyl-γ-pyrone (maltol). The aqueous filtrate was extracted with CHCl3 to obtain a second crop of 2.58 g of maltol. Distillation of the combined solids and recrystallization from methanol gave 5.5 g (49%) of pure white maltol, m.p. 159.5°-160.5° C. In a 3-neck round bottom flask equipped with a magnetic stirring bar, a gas inlet tube The solution was cooled to a temperature of 0° to 10° C was added via the gas inlet tube The rate of addition while maintaining the reaction temperature below 10° C The reaction mixture was heated to reflux the tetrahydrofuran removed by distillation a temperature of about 105° C., a condenser was added The reaction mixture was then filtered hot cooled Crystallization and filtration

反应条件: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a 3-neck round bottom flask is charged a solution of 50 ml of water and 20 ml of tetrahydrofuran and the solution is cooled to 0° C. An addition funnel is charged with a solution of 1(2-furyl)-1-ethanol (0.89 mole) in 25 ml of tetrahydrofuran and this solution is added dropwise to the reaction flask while BrCl (0.30 mole) is added via a gas inlet tube. The rate of addition is such that all the furfuryl alcohol is added in the first 1.3-1.5 equivalents of BrCl while maintaining the temperature below 30° C. The reaction mixture is heated to reflux and the tetrahydrofuran removed by distillation. When the temperature reaches 105° C., a condensor is attached and the reaction mixture heated under reflux for about 2 hours. The reaction mixture is cooled and maltol isolated by the method of Example 1. is added via a gas inlet tube The rate of addition while maintaining the temperature below 30° C The reaction mixture is heated to reflux the tetrahydrofuran removed by distillation reaches 105° C. the reaction mixture heated under reflux for about 2 hours The reaction mixture is cooled

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a solution of 1(2-furyl)-1-ethanol (0.05 mole) in 15 ml of tetrahydrofuran and 15 ml of water at 5° C. is added 21.7 ml of 2.8 M sodium hypochlorite solution. Chlorine (0.05 mole) is added to the reaction flask via a gas inlet tube maintaining the reaction temperature below 5° C. The reaction mixture is then heated to reflux and the tetrahydrofuran removed by distillation. Heating is continued for an additional hour. The reaction mixture is cooled and maltol is isolated by the procedure described in Example 1. maintaining the reaction temperature below 5° C The reaction mixture is then heated to reflux the tetrahydrofuran removed by distillation Heating is continued for an additional hour The reaction mixture is cooled

反应条件: temp:10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a 4-neck round bottom flask equipped with a thermometer, a condensor and two addition funnels was charged 50 ml of tetrahydrofuran and 50 ml of water and the solution was cooled to 10° C. To this well stirred solution was added together in the two addition funnels bromine (0.20 mole) and 1(2-furyl)-1-ethanol (0.09 mole). The temperature of the reaction was maintained at 15° C. throughout the double addition. The reaction mixture was then heated to 75° C. for 10 hours. Maltol was isolated by the procedure of Example 1 (53% yield). To a 4-neck round bottom flask equipped with a thermometer a condensor and two addition funnels The temperature of the reaction was maintained at 15° C. throughout the double addition The reaction mixture was then heated to 75° C. for 10 hours

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: In a 3-neck round bottom flask equipped with a stirring bar, a gas inlet tube and an addition funnel was added 20 ml of tetrahydrofuran, 50 ml of water and sodium bromide (0.20 mole). The solution was cooled to a temperature of 0° to 20° C. The addition funnel was charged with a solution of 1(2-furyl)-1-ethanol (0.18 mole) in 20 ml of tetrahydrofuran and this was added dropwise to the rapidly stirred reaction flask while gaseous chlorine (0.40 mole) is added via the gaseous inlet tube. The rate of the alcohol addition was such that a yellow orange color was maintained. The reaction temperature was kept below 20° C. with ice bath cooling. After the alcohol and chlorine had both been added to the reaction flask, the temperature was raised to reflux to distill off the tetrahydrofuran. The isolation procedure of Example 1 was used to isolate 12.47 g of pure maltol (55% yield). In a 3-neck round bottom flask equipped with a stirring bar, a gas inlet tube and an addition funnel The solution was cooled to a temperature of 0° to 20° C is added via the gaseous inlet tube was maintained The reaction temperature was kept below 20° C. with ice bath cooling both been added to the reaction flask the temperature was raised to reflux to distill off the tetrahydrofuran

反应条件: temp:5.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: In a 3-neck round bottom flask equipped with a magnetic stirring bar, a gas inlet tube, a thermometer and an addition funnel was added 20 ml of tetrahydrofuran and 50 ml of water. The solution was cooled to a temperature of 0° to 10° C. The addition funnel was charged with a solution of 1(2-furyl)-1-ethanol (0.089 moles) in 20 ml of tetrahydrofuran and this was added dropwise to the stirred reaction flask while chlorine (0.30 mole) was added via the gas inlet tube. The rate of addition was such that all the alcohol was added in the first 1.3-1.5 equivalents of chlorine (approximately 30 minutes) while maintaining the reaction temperature below 10° C. The reaction mixture was heated to reflux and the tetrahydrofuran removed by distillation. When the reaction mixture reached a temperature of about 105° C., a condenser was added and the refluxing continued for about 2 hours. The reaction mixture was then filtered hot, cooled, the pH adjusted to 2.2 and the reaction mixture was cooled to 5° C. Crystallization and filtration yielded 3.43 grams of crude 3-hydroxy-2-methyl-γ-pyrone (maltol). The aqueous filtrate was extracted with CHCl3 to obtain a second crop of 2.58 g of maltol. Distillation of the combined solids and recrystallization from methanol gave 5.5 g (49%) of pure white maltol, m.p. 159.5°-160.5° C. In a 3-neck round bottom flask equipped with a magnetic stirring bar, a gas inlet tube The solution was cooled to a temperature of 0° to 10° C was added via the gas inlet tube The rate of addition while maintaining the reaction temperature below 10° C The reaction mixture was heated to reflux the tetrahydrofuran removed by distillation a temperature of about 105° C., a condenser was added The reaction mixture was then filtered hot cooled Crystallization and filtration

反应条件: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a 3-neck round bottom flask is charged a solution of 50 ml of water and 20 ml of tetrahydrofuran and the solution is cooled to 0° C. An addition funnel is charged with a solution of 1(2-furyl)-1-ethanol (0.89 mole) in 25 ml of tetrahydrofuran and this solution is added dropwise to the reaction flask while BrCl (0.30 mole) is added via a gas inlet tube. The rate of addition is such that all the furfuryl alcohol is added in the first 1.3-1.5 equivalents of BrCl while maintaining the temperature below 30° C. The reaction mixture is heated to reflux and the tetrahydrofuran removed by distillation. When the temperature reaches 105° C., a condensor is attached and the reaction mixture heated under reflux for about 2 hours. The reaction mixture is cooled and maltol isolated by the method of Example 1. is added via a gas inlet tube The rate of addition while maintaining the temperature below 30° C The reaction mixture is heated to reflux the tetrahydrofuran removed by distillation reaches 105° C. the reaction mixture heated under reflux for about 2 hours The reaction mixture is cooled