(3R,4R)-1-苄基-4-甲氧基吡咯烷-3-胺

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

实验步骤: Trans-3-amino-1-benzyl-4-methoxypyrrolidine (racemic; 22.4 g) disclosed in Japanese Laid-open Patent Publication No. 69474/1990 and 19.6 g of L-tartaric acid were dissolved in methanol (350 ml), and the resulting solution was left still at room temperature for 7 hours. Precipitated L-tartrate was taken by filtration, and then, was subjected to recrystallization with methanol and water, and thus, there was obtained trans-3-amino-1-benzyl-4-methoxypyrrolidine L-tartrate (14.1 g) having the following physical properties. Then, all the mother liquors were put together, and the solvent was distilled off under reduced pressure, and then, a saturated brine was added, and, subsequently, potassium carbonate was added so that the obtained mixture might become basic. Then, the mixture was extracted with ethyl acetate. The obtained extract was washed with saturated brine, and was then dried over anhydrous sodium sulfate, and solvent was distilled off under reduced pressure. The resultant residue and D-tartaric acid (6.73 g) were dissolved in methanol (180 ml), and the obtained solution was left still at room temperature for 7 hours. Precipitated D-tartrate was taken by filtration, and was then subjected to recrystallization with methanol and water, and thus, there was obtained trans-3-amino-1-benzyl-4-methoxypyrrolidine D-tartrate (9.9 g) having the following physical properties. Precipitated L-tartrate was taken by filtration was subjected to recrystallization with methanol and water

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

实验步骤: 27 g (0.41 mmol) of sodim azide are dissolved in 50 ml of water, and 17.5 g (0.1 mol) of 3-benzyl-6-oxa-3-azabicyclo[3.1.0]hexane in 300 ml of dioxane are added. The mixture is heated under reflux for 72 hours and concentrated, the inorganic salts are dissolved in water and the mixture is extracted with chloroform. The extract is dried over potassium carbonate and concentrated. The residue is dissolved in 50 ml of absolute tetrahydrofuran and the solution is added dropwise to 4 g of sodium hydride (80% strength in paraffin oil) in 200 ml of absolute tetrahydrofuran. The mixture is heated under reflux for one hour and 15 g (0.1 mol) of methyl iodide are then added dropwise. The mixture is subsequently heated under reflux overnight and concentrated, the residue is taken up in water and the mixture is extracted with chloroform. The extract is dried over potassium carbonate and concentrated and the residue is distilled. 13.1 g of a material which is 73% pure according to the gas chromatogram are obtained. 12.7 g of this material in 40 ml of absolute tetrahydrofuran are added dropwise to a suspension of 4 g of lithium aluminum hydride in 150 ml of absolute tetrahydrofuran and the mixture is heated under reflux for 2 hours. Excess lithium aluminum hydride is decomposed by careful dropwise addition of 4 ml portions of water and 15% strength potassium hydroxide solution and again 4 ml of water. The inorganic salts are filtered off with suction and washed several times with chloroform. The organic phases are dried over potassium carbonate and concentrated and the residue is distilled. The mixture is heated under reflux for 72 hours concentrated the inorganic salts are dissolved in water the mixture is extracted with chloroform The extract is dried over potassium carbonate concentrated The residue is dissolved in 50 ml of absolute tetrahydrofuran the solution is added dropwise to 4 g of sodium hydride (80% strength in paraffin oil) in 200 ml of absolute tetrahydrofuran The mixture is heated under reflux for one hour The mixture is subsequently heated under reflux overnight concentrated the mixture is extracted with chloroform The extract is dried over potassium carbonate concentrated the residue is distilled are obtained the mixture is heated under reflux for 2 hours The inorganic salts are filtered off with suction washed several times with chloroform The organic phases are dried over potassium carbonate concentrated the residue is distilled

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

实验步骤: 27 g (0.41 mol) of sodium azide are dissolved in 50 ml of water, and 17.5 g (0.1 mol) of 3-benzyl-6-oxa-3-azabicyclo[3.1.0]hexane in 300 ml of dioxane are added. The mixture is heated under reflux for 72 hours and concentrated, the inorganic salts are dissolved in water and the mixture is extracted with chloroform. The extract is dried over potassium carbonate and concentrated. The residue is dissolved in 50 ml of absolute tetrahydrofuran and the solution is added dropwise to 4 g of sodium hydride (80% strength in paraffin oil) in 200 ml of absolute tetrahydrofuran. The mixture is heated under reflux for one hour and 15 g (0.1 mol) of methyl iodide are then added dropwise. The mixture is subsequently heated under reflux overnight and concentrated, the residue is taken up in water and the mixture is extracted with chloroform. The extract is dried over potassium carbonate and concentrated and the residue is distilled. 13.1 g of a material which is 73% pure according to the gas chromatogram are obtained. 12.7 g of this material in 40 ml of absolute tetrahydrofuran are added dropwise to a suspension of 4 g of lithium aluminum hydride in 150 ml of absolute tetrahydrofuran and the mixture is heated under reflux for 2 hours. Excess lithium aluminum hydride is decomposed by careful dropwise addition of 4 ml portions of water and 15% strength potassium hydroxide solution and again 4 ml of water. The inorganic salts are filtered off with suction and washed several times with chloroform. The organic phases are dried over potassium carbonate and concentrated and the residue is distilled. The mixture is heated under reflux for 72 hours concentrated the inorganic salts are dissolved in water the mixture is extracted with chloroform The extract is dried over potassium carbonate concentrated The residue is dissolved in 50 ml of absolute tetrahydrofuran the solution is added dropwise to 4 g of sodium hydride (80% strength in paraffin oil) in 200 ml of absolute tetrahydrofuran The mixture is heated under reflux for one hour The mixture is subsequently heated under reflux overnight concentrated the mixture is extracted with chloroform The extract is dried over potassium carbonate concentrated the residue is distilled are obtained the mixture is heated under reflux for 2 hours The inorganic salts are filtered off with suction washed several times with chloroform The organic phases are dried over potassium carbonate concentrated the residue is distilled

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

实验步骤: 27 g (0.41 mol) of sodium azide are dissolved in 50 ml of water, and 17.5 g (0.1 mol) of 3-benzyl-6-oxa-3-azabicyclo[3.1.0]hexane in 300 ml of dioxane are added. The mixture is heated under reflux for 72 hours and concentrated, the inorganic salts are dissolved in water and the mixture is extracted with chloroform. The extract is dried over potassium carbonate and concentrated. The residue is dissolved in 50 ml of absolute tetrahydrofuran and the solution is added dropwise to 4 g of sodium hydride (80% strength in paraffin oil) in 200 ml of absolute tetrahydrofuran. The mixture is heated under reflux for one hour and 15 g (0.1 mol) of methyl iodide are then added dropwise. The mixture is subsequently heated under reflux overnight and concentrated, the residue is taken up in water and the mixture is extracted with chloroform. The extract is dried over potassium carbonate and concentrated and the residue is distilled. 13.1 g of a material which is 73% pure according to the gas chromatogram are obtained. 12.7 g of this material in 40 ml of absolute tetrahydrofuran are added dropwise to a suspension of 4 g of lithium aluminum hydride in 150 ml of absolute tetrahydrofuran and the mixture is heated under reflux for 2 hours. Excess lithium aluminum hydride is decomposed by careful dropwise addition of 4 ml portions of water and 15% strength potassium hydroxide solution and again 4 ml of water. The inorganic salts are filtered off with suction and washed several times with chloroform. The organic phases are dried over potassium carbonate and concentrated and the residue is distilled. The mixture is heated under reflux for 72 hours concentrated the inorganic salts are dissolved in water the mixture is extracted with chloroform The extract is dried over potassium carbonate concentrated The residue is dissolved in 50 ml of absolute tetrahydrofuran the solution is added dropwise to 4 g of sodium hydride (80% strength in paraffin oil) in 200 ml of absolute tetrahydrofuran The mixture is heated under reflux for one hour The mixture is subsequently heated under reflux overnight concentrated the mixture is extracted with chloroform The extract is dried over potassium carbonate concentrated the residue is distilled are obtained the mixture is heated under reflux for 2 hours The inorganic salts are filtered off with suction washed several times with chloroform The organic phases are dried over potassium carbonate concentrated the residue is distilled

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

实验步骤: Trans-3-amino-1-benzyl-4-methoxypyrrolidine (racemic; 22.4 g) disclosed in Japanese Laid-open Patent Publication No. 69474/1990 and 19.6 g of L-tartaric acid were dissolved in methanol (350 ml), and the resulting solution was left still at room temperature for 7 hours. Precipitated L-tartrate was taken by filtration, and then, was subjected to recrystallization with methanol and water, and thus, there was obtained trans-3-amino-1-benzyl-4-methoxypyrrolidine L-tartrate (14.1 g) having the following physical properties. Then, all the mother liquors were put together, and the solvent was distilled off under reduced pressure, and then, a saturated brine was added, and, subsequently, potassium carbonate was added so that the obtained mixture might become basic. Then, the mixture was extracted with ethyl acetate. The obtained extract was washed with saturated brine, and was then dried over anhydrous sodium sulfate, and solvent was distilled off under reduced pressure. The resultant residue and D-tartaric acid (6.73 g) were dissolved in methanol (180 ml), and the obtained solution was left still at room temperature for 7 hours. Precipitated D-tartrate was taken by filtration, and was then subjected to recrystallization with methanol and water, and thus, there was obtained trans-3-amino-1-benzyl-4-methoxypyrrolidine D-tartrate (9.9 g) having the following physical properties. Precipitated L-tartrate was taken by filtration was subjected to recrystallization with methanol and water

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

实验步骤: 27 g (0.41 mmol) of sodim azide are dissolved in 50 ml of water, and 17.5 g (0.1 mol) of 3-benzyl-6-oxa-3-azabicyclo[3.1.0]hexane in 300 ml of dioxane are added. The mixture is heated under reflux for 72 hours and concentrated, the inorganic salts are dissolved in water and the mixture is extracted with chloroform. The extract is dried over potassium carbonate and concentrated. The residue is dissolved in 50 ml of absolute tetrahydrofuran and the solution is added dropwise to 4 g of sodium hydride (80% strength in paraffin oil) in 200 ml of absolute tetrahydrofuran. The mixture is heated under reflux for one hour and 15 g (0.1 mol) of methyl iodide are then added dropwise. The mixture is subsequently heated under reflux overnight and concentrated, the residue is taken up in water and the mixture is extracted with chloroform. The extract is dried over potassium carbonate and concentrated and the residue is distilled. 13.1 g of a material which is 73% pure according to the gas chromatogram are obtained. 12.7 g of this material in 40 ml of absolute tetrahydrofuran are added dropwise to a suspension of 4 g of lithium aluminum hydride in 150 ml of absolute tetrahydrofuran and the mixture is heated under reflux for 2 hours. Excess lithium aluminum hydride is decomposed by careful dropwise addition of 4 ml portions of water and 15% strength potassium hydroxide solution and again 4 ml of water. The inorganic salts are filtered off with suction and washed several times with chloroform. The organic phases are dried over potassium carbonate and concentrated and the residue is distilled. The mixture is heated under reflux for 72 hours concentrated the inorganic salts are dissolved in water the mixture is extracted with chloroform The extract is dried over potassium carbonate concentrated The residue is dissolved in 50 ml of absolute tetrahydrofuran the solution is added dropwise to 4 g of sodium hydride (80% strength in paraffin oil) in 200 ml of absolute tetrahydrofuran The mixture is heated under reflux for one hour The mixture is subsequently heated under reflux overnight concentrated the mixture is extracted with chloroform The extract is dried over potassium carbonate concentrated the residue is distilled are obtained the mixture is heated under reflux for 2 hours The inorganic salts are filtered off with suction washed several times with chloroform The organic phases are dried over potassium carbonate concentrated the residue is distilled

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

实验步骤: 27 g (0.41 mmol) of sodim azide are dissolved in 50 ml of water, and 17.5 g (0.1 mol) of 3-benzyl-6-oxa-3-azabicyclo[3.1.0]hexane in 300 ml of dioxane are added. The mixture is heated under reflux for 72 hours and concentrated, the inorganic salts are dissolved in water and the mixture is extracted with chloroform. The extract is dried over potassium carbonate and concentrated. The residue is dissolved in 50 ml of absolute tetrahydrofuran and the solution is added dropwise to 4 g of sodium hydride (80% strength in paraffin oil) in 200 ml of absolute tetrahydrofuran. The mixture is heated under reflux for one hour and 15 g (0.1 mol) of methyl iodide are then added dropwise. The mixture is subsequently heated under reflux overnight and concentrated, the residue is taken up in water and the mixture is extracted with chloroform. The extract is dried over potassium carbonate and concentrated and the residue is distilled. 13.1 g of a material which is 73% pure according to the gas chromatogram are obtained. 12.7 g of this material in 40 ml of absolute tetrahydrofuran are added dropwise to a suspension of 4 g of lithium aluminum hydride in 150 ml of absolute tetrahydrofuran and the mixture is heated under reflux for 2 hours. Excess lithium aluminum hydride is decomposed by careful dropwise addition of 4 ml portions of water and 15% strength potassium hydroxide solution and again 4 ml of water. The inorganic salts are filtered off with suction and washed several times with chloroform. The organic phases are dried over potassium carbonate and concentrated and the residue is distilled. The mixture is heated under reflux for 72 hours concentrated the inorganic salts are dissolved in water the mixture is extracted with chloroform The extract is dried over potassium carbonate concentrated The residue is dissolved in 50 ml of absolute tetrahydrofuran the solution is added dropwise to 4 g of sodium hydride (80% strength in paraffin oil) in 200 ml of absolute tetrahydrofuran The mixture is heated under reflux for one hour The mixture is subsequently heated under reflux overnight concentrated the mixture is extracted with chloroform The extract is dried over potassium carbonate concentrated the residue is distilled are obtained the mixture is heated under reflux for 2 hours The inorganic salts are filtered off with suction washed several times with chloroform The organic phases are dried over potassium carbonate concentrated the residue is distilled

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

实验步骤: 27 g (0.41 mol) of sodium azide are dissolved in 50 ml of water, and 17.5 g (0.1 mol) of 3-benzyl-6-oxa-3-azabicyclo[3.1.0]hexane in 300 ml of dioxane are added. The mixture is heated under reflux for 72 hours and concentrated, the inorganic salts are dissolved in water and the mixture is extracted with chloroform. The extract is dried over potassium carbonate and concentrated. The residue is dissolved in 50 ml of absolute tetrahydrofuran and the solution is added dropwise to 4 g of sodium hydride (80% strength in paraffin oil) in 200 ml of absolute tetrahydrofuran. The mixture is heated under reflux for one hour and 15 g (0.1 mol) of methyl iodide are then added dropwise. The mixture is subsequently heated under reflux overnight and concentrated, the residue is taken up in water and the mixture is extracted with chloroform. The extract is dried over potassium carbonate and concentrated and the residue is distilled. 13.1 g of a material which is 73% pure according to the gas chromatogram are obtained. 12.7 g of this material in 40 ml of absolute tetrahydrofuran are added dropwise to a suspension of 4 g of lithium aluminum hydride in 150 ml of absolute tetrahydrofuran and the mixture is heated under reflux for 2 hours. Excess lithium aluminum hydride is decomposed by careful dropwise addition of 4 ml portions of water and 15% strength potassium hydroxide solution and again 4 ml of water. The inorganic salts are filtered off with suction and washed several times with chloroform. The organic phases are dried over potassium carbonate and concentrated and the residue is distilled. The mixture is heated under reflux for 72 hours concentrated the inorganic salts are dissolved in water the mixture is extracted with chloroform The extract is dried over potassium carbonate concentrated The residue is dissolved in 50 ml of absolute tetrahydrofuran the solution is added dropwise to 4 g of sodium hydride (80% strength in paraffin oil) in 200 ml of absolute tetrahydrofuran The mixture is heated under reflux for one hour The mixture is subsequently heated under reflux overnight concentrated the mixture is extracted with chloroform The extract is dried over potassium carbonate concentrated the residue is distilled are obtained the mixture is heated under reflux for 2 hours The inorganic salts are filtered off with suction washed several times with chloroform The organic phases are dried over potassium carbonate concentrated the residue is distilled

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

实验步骤: 27 g (0.41 mol) of sodium azide are dissolved in 50 ml of water, and 17.5 g (0.1 mol) of 3-benzyl-6-oxa-3-azabicyclo[3.1.0]hexane in 300 ml of dioxane are added. The mixture is heated under reflux for 72 hours and concentrated, the inorganic salts are dissolved in water and the mixture is extracted with chloroform. The extract is dried over potassium carbonate and concentrated. The residue is dissolved in 50 ml of absolute tetrahydrofuran and the solution is added dropwise to 4 g of sodium hydride (80% strength in paraffin oil) in 200 ml of absolute tetrahydrofuran. The mixture is heated under reflux for one hour and 15 g (0.1 mol) of methyl iodide are then added dropwise. The mixture is subsequently heated under reflux overnight and concentrated, the residue is taken up in water and the mixture is extracted with chloroform. The extract is dried over potassium carbonate and concentrated and the residue is distilled. 13.1 g of a material which is 73% pure according to the gas chromatogram are obtained. 12.7 g of this material in 40 ml of absolute tetrahydrofuran are added dropwise to a suspension of 4 g of lithium aluminum hydride in 150 ml of absolute tetrahydrofuran and the mixture is heated under reflux for 2 hours. Excess lithium aluminum hydride is decomposed by careful dropwise addition of 4 ml portions of water and 15% strength potassium hydroxide solution and again 4 ml of water. The inorganic salts are filtered off with suction and washed several times with chloroform. The organic phases are dried over potassium carbonate and concentrated and the residue is distilled. The mixture is heated under reflux for 72 hours concentrated the inorganic salts are dissolved in water the mixture is extracted with chloroform The extract is dried over potassium carbonate concentrated The residue is dissolved in 50 ml of absolute tetrahydrofuran the solution is added dropwise to 4 g of sodium hydride (80% strength in paraffin oil) in 200 ml of absolute tetrahydrofuran The mixture is heated under reflux for one hour The mixture is subsequently heated under reflux overnight concentrated the mixture is extracted with chloroform The extract is dried over potassium carbonate concentrated the residue is distilled are obtained the mixture is heated under reflux for 2 hours The inorganic salts are filtered off with suction washed several times with chloroform The organic phases are dried over potassium carbonate concentrated the residue is distilled

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

实验步骤: 27 g (0.41 mol) of sodium azide are dissolved in 50 ml of water, and 17.5 g (0.1 mol) of 3-benzyl-6-oxa-3-azabicyclo[3.1.0]hexane in 300 ml of dioxane are added. The mixture is heated under reflux for 72 hours and concentrated, the inorganic salts are dissolved in water and the mixture is extracted with chloroform. The extract is dried over potassium carbonate and concentrated. The residue is dissolved in 50 ml of absolute tetrahydrofuran and the solution is added dropwise to 4 g of sodium hydride (80% strength in paraffin oil) in 200 ml of absolute tetrahydrofuran. The mixture is heated under reflux for one hour and 15 g (0.1 mol) of methyl iodide are then added dropwise. The mixture is subsequently heated under reflux overnight and concentrated, the residue is taken up in water and the mixture is extracted with chloroform. The extract is dried over potassium carbonate and concentrated and the residue is distilled. 13.1 g of a material which is 73% pure according to the gas chromatogram are obtained. 12.7 g of this material in 40 ml of absolute tetrahydrofuran are added dropwise to a suspension of 4 g of lithium aluminum hydride in 150 ml of absolute tetrahydrofuran and the mixture is heated under reflux for 2 hours. Excess lithium aluminum hydride is decomposed by careful dropwise addition of 4 ml portions of water and 15% strength potassium hydroxide solution and again 4 ml of water. The inorganic salts are filtered off with suction and washed several times with chloroform. The organic phases are dried over potassium carbonate and concentrated and the residue is distilled. The mixture is heated under reflux for 72 hours concentrated the inorganic salts are dissolved in water the mixture is extracted with chloroform The extract is dried over potassium carbonate concentrated The residue is dissolved in 50 ml of absolute tetrahydrofuran the solution is added dropwise to 4 g of sodium hydride (80% strength in paraffin oil) in 200 ml of absolute tetrahydrofuran The mixture is heated under reflux for one hour The mixture is subsequently heated under reflux overnight concentrated the mixture is extracted with chloroform The extract is dried over potassium carbonate concentrated the residue is distilled are obtained the mixture is heated under reflux for 2 hours The inorganic salts are filtered off with suction washed several times with chloroform The organic phases are dried over potassium carbonate concentrated the residue is distilled

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

实验步骤: Trans-3-amino-1-benzyl-4-methoxypyrrolidine (racemic; 22.4 g) disclosed in Japanese Laid-open Patent Publication No. 69474/1990 and 19.6 g of L-tartaric acid were dissolved in methanol (350 ml), and the resulting solution was left still at room temperature for 7 hours. Precipitated L-tartrate was taken by filtration, and then, was subjected to recrystallization with methanol and water, and thus, there was obtained trans-3-amino-1-benzyl-4-methoxypyrrolidine L-tartrate (14.1 g) having the following physical properties. Then, all the mother liquors were put together, and the solvent was distilled off under reduced pressure, and then, a saturated brine was added, and, subsequently, potassium carbonate was added so that the obtained mixture might become basic. Then, the mixture was extracted with ethyl acetate. The obtained extract was washed with saturated brine, and was then dried over anhydrous sodium sulfate, and solvent was distilled off under reduced pressure. The resultant residue and D-tartaric acid (6.73 g) were dissolved in methanol (180 ml), and the obtained solution was left still at room temperature for 7 hours. Precipitated D-tartrate was taken by filtration, and was then subjected to recrystallization with methanol and water, and thus, there was obtained trans-3-amino-1-benzyl-4-methoxypyrrolidine D-tartrate (9.9 g) having the following physical properties. Precipitated L-tartrate was taken by filtration was subjected to recrystallization with methanol and water

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

实验步骤: 27 g (0.41 mmol) of sodim azide are dissolved in 50 ml of water, and 17.5 g (0.1 mol) of 3-benzyl-6-oxa-3-azabicyclo[3.1.0]hexane in 300 ml of dioxane are added. The mixture is heated under reflux for 72 hours and concentrated, the inorganic salts are dissolved in water and the mixture is extracted with chloroform. The extract is dried over potassium carbonate and concentrated. The residue is dissolved in 50 ml of absolute tetrahydrofuran and the solution is added dropwise to 4 g of sodium hydride (80% strength in paraffin oil) in 200 ml of absolute tetrahydrofuran. The mixture is heated under reflux for one hour and 15 g (0.1 mol) of methyl iodide are then added dropwise. The mixture is subsequently heated under reflux overnight and concentrated, the residue is taken up in water and the mixture is extracted with chloroform. The extract is dried over potassium carbonate and concentrated and the residue is distilled. 13.1 g of a material which is 73% pure according to the gas chromatogram are obtained. 12.7 g of this material in 40 ml of absolute tetrahydrofuran are added dropwise to a suspension of 4 g of lithium aluminum hydride in 150 ml of absolute tetrahydrofuran and the mixture is heated under reflux for 2 hours. Excess lithium aluminum hydride is decomposed by careful dropwise addition of 4 ml portions of water and 15% strength potassium hydroxide solution and again 4 ml of water. The inorganic salts are filtered off with suction and washed several times with chloroform. The organic phases are dried over potassium carbonate and concentrated and the residue is distilled. The mixture is heated under reflux for 72 hours concentrated the inorganic salts are dissolved in water the mixture is extracted with chloroform The extract is dried over potassium carbonate concentrated The residue is dissolved in 50 ml of absolute tetrahydrofuran the solution is added dropwise to 4 g of sodium hydride (80% strength in paraffin oil) in 200 ml of absolute tetrahydrofuran The mixture is heated under reflux for one hour The mixture is subsequently heated under reflux overnight concentrated the mixture is extracted with chloroform The extract is dried over potassium carbonate concentrated the residue is distilled are obtained the mixture is heated under reflux for 2 hours The inorganic salts are filtered off with suction washed several times with chloroform The organic phases are dried over potassium carbonate concentrated the residue is distilled