乙基3,4-二氢-2H-吡喃-2-羧酸盐

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

实验步骤: A mixture of sodium 3,4-dihydro-2H-pyran-2-carboxylate (150.0 g, 10 mol), ethyl iodide (192.3 g, 1.2 mol), sodium carbonate (10 g), and dimethylformamide (500 ml) was heated at 105°-110° C. for 5 hours. The reaction mixture was cooled to room temperature and water (450 ml) was added to dissolve inorganic sales. The mixture was extracted with four 200 ml portions of benzene. The combined organic layers were washed with four 200 ml portions of water and dried over anhydrous magnesium sulfate. The solution was filtered and the solvent was removed by rotary evaporation. The oily residue was distilled under reduced pressure giving a yield of 87% of product having a bp of 75°-80° C. was heated at 105°-110° C. for 5 hours to dissolve inorganic sales The mixture was extracted with four 200 ml portions of benzene The combined organic layers were washed with four 200 ml portions of water dried over anhydrous magnesium sulfate The solution was filtered the solvent was removed by rotary evaporation The oily residue was distilled under reduced pressure

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

实验步骤: The synthesis of 2,5-dioxabicyclo[2.2.2]octan-3 one was achieved through a three step reaction sequence as illustrated below: ##STR3## Sodium 3,4-dihydro-2H-Pyran-2-carboxylate was esterified with ethyl iodide in dimethylformamide to afford ethyl 3,4-dihydro-2H-pyran-2-carboxylate. Subsequent hydroboration with a borane solution in tetrahydropyran at 0° C., followed by oxidation with a sodium dichromate-sulfuric acid aqueous solution and subsequent treatment with sodium hydrogen sulfite gave ethyl 5-hydroxytetrahydropyran-2-carboxylate as a stereoisomer mixture. The hydroxytetrahydropyran ester was heated in a dilute solution in the presence of a catalytic amount of p-toluenesulfonic acid, any ethyl alcohol being liberated was removed through a Soxhlet extractor containing type 5A molecular sieves. Column chromatographic separation of the reaction products and subsequent repeated recrystallization gave the bicyclic lactone as colorless crystals; the overall yield was approximately 20%.

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

实验步骤: The synthesis of 2,5-dioxabicyclo[2.2.2]octan-3 one was achieved through a three step reaction sequence as illustrated below: ##STR3## Sodium 3,4-dihydro-2H-Pyran-2-carboxylate was esterified with ethyl iodide in dimethylformamide to afford ethyl 3,4-dihydro-2H-pyran-2-carboxylate. Subsequent hydroboration with a borane solution in tetrahydropyran at 0° C., followed by oxidation with a sodium dichromate-sulfuric acid aqueous solution and subsequent treatment with sodium hydrogen sulfite gave ethyl 5-hydroxytetrahydropyran-2-carboxylate as a stereoisomer mixture. The hydroxytetrahydropyran ester was heated in a dilute solution in the presence of a catalytic amount of p-toluenesulfonic acid, any ethyl alcohol being liberated was removed through a Soxhlet extractor containing type 5A molecular sieves. Column chromatographic separation of the reaction products and subsequent repeated recrystallization gave the bicyclic lactone as colorless crystals; the overall yield was approximately 20%.

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

实验步骤: A mixture of sodium 3,4-dihydro-2H-pyran-2-carboxylate (150.0 g, 10 mol), ethyl iodide (192.3 g, 1.2 mol), sodium carbonate (10 g), and dimethylformamide (500 ml) was heated at 105°-110° C. for 5 hours. The reaction mixture was cooled to room temperature and water (450 ml) was added to dissolve inorganic sales. The mixture was extracted with four 200 ml portions of benzene. The combined organic layers were washed with four 200 ml portions of water and dried over anhydrous magnesium sulfate. The solution was filtered and the solvent was removed by rotary evaporation. The oily residue was distilled under reduced pressure giving a yield of 87% of product having a bp of 75°-80° C. was heated at 105°-110° C. for 5 hours to dissolve inorganic sales The mixture was extracted with four 200 ml portions of benzene The combined organic layers were washed with four 200 ml portions of water dried over anhydrous magnesium sulfate The solution was filtered the solvent was removed by rotary evaporation The oily residue was distilled under reduced pressure

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

实验步骤: The synthesis of 2,5-dioxabicyclo[2.2.2]octan-3 one was achieved through a three step reaction sequence as illustrated below: ##STR3## Sodium 3,4-dihydro-2H-Pyran-2-carboxylate was esterified with ethyl iodide in dimethylformamide to afford ethyl 3,4-dihydro-2H-pyran-2-carboxylate. Subsequent hydroboration with a borane solution in tetrahydropyran at 0° C., followed by oxidation with a sodium dichromate-sulfuric acid aqueous solution and subsequent treatment with sodium hydrogen sulfite gave ethyl 5-hydroxytetrahydropyran-2-carboxylate as a stereoisomer mixture. The hydroxytetrahydropyran ester was heated in a dilute solution in the presence of a catalytic amount of p-toluenesulfonic acid, any ethyl alcohol being liberated was removed through a Soxhlet extractor containing type 5A molecular sieves. Column chromatographic separation of the reaction products and subsequent repeated recrystallization gave the bicyclic lactone as colorless crystals; the overall yield was approximately 20%.