3,3-dimethoxypentane

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: In 150 ml of 3,3-dimethoxypentane was dissolved 25 g of (S)(-)-butanetriol, and 0.1 g of p-toluenesulfonic acid was added to the solution. The solution was stirred for 16 hr to conduct a reaction. The resultant reaction mixture was poured into a saturated aqueous solution of sodium hydrogencarbonate, the reaction product was extracted with an ether, and the extract was washed with a saturated saline solution. The solvent was distilled off from the extract as washed, and the resultant residue was purified by a silica gel column chromatography through the use of hexane-ethyl acetate as a developing solvent to obtain 26.5 g of (S)-2,2-diethyl-4-(2-hydroxyethyl)-1,3-dioxolane. The whole quantity of the product was dissolved in 500 ml of benzene, and 24 g of imidazole, 100 g of triphenylphosphine and 40 g of iodine were added to the solution. The mixture was stirred for 2 hr and then poured into ice water. The reaction product was extracted with an ether, and the extract was well washed with a 10% aqueous solution of sodium thiosulfate and dried over magnesium sulfate. The solvent was removed from the dried reaction product by distillation, and the resultant residue was purified by a silica gel column chromatography through the use of hexane-ethyl acetate as a developing solvent to obtain 31 g of (S)-2,2-diethyl-4-(2-iodoethyl)-1,3-dioxolane. was added to the solution a reaction The resultant reaction mixture the reaction product was extracted with an ether the extract was washed with a saturated saline solution The solvent was distilled off from the extract as washed the resultant residue was purified by a silica gel column chromatography through the use of hexane-ethyl acetate as a developing solvent

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

Procedure: In 150 ml of 3,3-dimethoxypentane was dissolved 25 g of (S)(-)-butanetriol, and 0.1 g of p-toluenesulfonic acid was added to the solution. The solution was stirred for 16 hr to conduct a reaction. The resultant reaction mixture was poured into a saturated aqueous solution of sodium hydrogencarbonate, the reaction product was extracted with an ether, and the extract was washed with a saturated saline solution. The solvent was distilled off from the extract as washed, and the resultant residue was purified by a silica gel column chromatography through the use of hexane-ethyl acetate as a developing solvent to obtain 26.5 g of (S)-2,2-diethyl-4-(2-hydroxyethyl)-1,3-dioxolane. The whole quantity of the product was dissolved in 500 ml of benzene, and 24 g of imidazole, 100 g of triphenylphosphine and 40 g of iodine were added to the solution. The mixture was stirred for 2 hr and then poured into ice water. The reaction product was extracted with an ether, and the extract was well washed with a 10% aqueous solution of sodium thiosulfate and dried over magnesium sulfate. The solvent was removed from the dried reaction product by distillation, and the resultant residue was purified by a silica gel column chromatography through the use of hexane-ethyl acetate as a developing solvent to obtain 31 g of (S)-2,2-diethyl-4-(2-iodoethyl)-1,3-dioxolane. was added to the solution a reaction The resultant reaction mixture the reaction product was extracted with an ether the extract was washed with a saturated saline solution The solvent was distilled off from the extract as washed the resultant residue was purified by a silica gel column chromatography through the use of hexane-ethyl acetate as a developing solvent

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

Procedure: In 150 ml of 3,3-dimethoxypentane was dissolved 25 g of (S)(-)-butanetriol, and 0.1 g of p-toluenesulfonic acid was added to the solution. The solution was stirred for 16 hr to conduct a reaction. The resultant reaction mixture was poured into a saturated aqueous solution of sodium hydrogencarbonate, the reaction product was extracted with an ether, and the extract was washed with a saturated saline solution. The solvent was distilled off from the extract as washed, and the resultant residue was purified by a silica gel column chromatography through the use of hexane-ethyl acetate as a developing solvent to obtain 26.5 g of (S)-2,2-diethyl-4-(2-hydroxyethyl)-1,3-dioxolane. The whole quantity of the product was dissolved in 500 ml of benzene, and 24 g of imidazole, 100 g of triphenylphosphine and 40 g of iodine were added to the solution. The mixture was stirred for 2 hr and then poured into ice water. The reaction product was extracted with an ether, and the extract was well washed with a 10% aqueous solution of sodium thiosulfate and dried over magnesium sulfate. The solvent was removed from the dried reaction product by distillation, and the resultant residue was purified by a silica gel column chromatography through the use of hexane-ethyl acetate as a developing solvent to obtain 31 g of (S)-2,2-diethyl-4-(2-iodoethyl)-1,3-dioxolane. was added to the solution a reaction The resultant reaction mixture the reaction product was extracted with an ether the extract was washed with a saturated saline solution The solvent was distilled off from the extract as washed the resultant residue was purified by a silica gel column chromatography through the use of hexane-ethyl acetate as a developing solvent

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:20.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 2.5 g of ethyl (2R,3S)-3-tert-butoxycarbonylamino-2-hydroxy-3-phenylpropionate, 1.12 g of 3,3-dimethoxypentane and 25 mg of pyridinium p-toluene-sulphonate in 25 cm3 of toluene is stirred for 3 hours at a temperature in the region of 20° C. The reaction mixture is heated to boiling and the distillate is collected in a graduated vessel. After 20 cm3 of distillate have been collected, a solution of 1.12 g of 3,3-dimethoxypentane and 25 mg of pyridinium p-toluenesulphonate in 10 cm3 of toluene is added to the reaction medium and the mixture is heated to reflux of the toluene for 5 hours. The reaction medium is cooled to a temperature in the region of 20° C. and 10 cm3 of saturated aqueous sodium hydrogen carbonate solution are then added. The aqueous phase is separated after settling has taken place and then extracted with 2 times 10 cm3 of dichloromethane. The organic phases are combined, dried over magnesium sulphate, filtered and concentrated to dryness under reduced pressure (2.7 kPa) at a temperature in the region of 40° C. 2.3 g of ethyl (4S,5R)-3-tert-butoxycarbonyl-2,2-diethyl-4-phenyl-5-oxazolidinecarboxylate are thereby obtained in the form of a yellow oil. The reaction mixture is heated the distillate is collected in a graduated vessel After 20 cm3 of distillate have been collected a solution of 1.12 g of 3,3-dimethoxypentane and 25 mg of pyridinium p-toluenesulphonate in 10 cm3 of toluene is added to the reaction medium the mixture is heated to reflux of the toluene for 5 hours are then added The aqueous phase is separated after settling extracted with 2 times 10 cm3 of dichloromethane dried over magnesium sulphate filtered concentrated to dryness under reduced pressure (2.7 kPa) at a temperature in the region of 40° C

Conditions: temp:5.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: First, 43.11 g (50.1 mmol) of 3-pentanone, 43.11 g (1.35 mol) of methanol, and 0.43 g (2.26 mmol) of p-toluenesulfonic acid monohydrate were added to a 3-necked flask (300 ml volume) equipped with a thermometer, a mechanical stirrer and a dropping funnel, and cooled to 5° C. Next, 63.03 g (525 mmol) of trimethyl orthoacetate was added dropwise to this solution over a period of 90 minutes while keeping internal temperature at 10° C. or lower. Then the temperature of the reaction mixture was raised to room temperature and the reaction mixture was agitated for 2 hours. The reaction solution was neutralized with 1.0 g (4.63 mmol) of 25% sodium methoxide/methanol solution, and then distilled under reduced pressure to give 59.34 g of 3,3-dimethoxypentane (boiling point: 55-57° C./50 torr, yield of approximately 100%). equipped with a thermometer, a mechanical stirrer and a dropping funnel at 10° C. Then the temperature of the reaction mixture was raised to room temperature distilled under reduced pressure

Conditions: temp:5.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: First, 43.11 g (50.1 mmol) of 3-pentanone, 43.11 g (1.35 mol) of methanol, and 0.43 g (2.26 mmol) of p-toluenesulfonic acid monohydrate were added to a 3-necked flask (300 ml volume) equipped with a thermometer, a mechanical stirrer and a dropping funnel, and cooled to 5° C. Next, 63.03 g (525 mmol) of trimethyl orthoacetate was added dropwise to this solution over a period of 90 minutes while keeping internal temperature at 10° C. or lower. Then the temperature of the reaction mixture was raised to room temperature and the reaction mixture was agitated for 2 hours. The reaction solution was neutralized with 1.0 g (4.63 mmol) of 25% sodium methoxide/methanol solution, and then distilled under reduced pressure to give 59.34 g of 3,3-dimethoxypentane (boiling point: 55-57° C./50 torr, yield of approximately 100%). equipped with a thermometer, a mechanical stirrer and a dropping funnel at 10° C. Then the temperature of the reaction mixture was raised to room temperature distilled under reduced pressure

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

Procedure: In 150 ml of 3,3-dimethoxypentane was dissolved 25 g of (S)(-)-butanetriol, and 0.1 g of p-toluenesulfonic acid was added to the solution. The solution was stirred for 16 hr to conduct a reaction. The resultant reaction mixture was poured into a saturated aqueous solution of sodium hydrogencarbonate, the reaction product was extracted with an ether, and the extract was washed with a saturated saline solution. The solvent was distilled off from the extract as washed, and the resultant residue was purified by a silica gel column chromatography through the use of hexane-ethyl acetate as a developing solvent to obtain 26.5 g of (S)-2,2-diethyl-4-(2-hydroxyethyl)-1,3-dioxolane. The whole quantity of the product was dissolved in 500 ml of benzene, and 24 g of imidazole, 100 g of triphenylphosphine and 40 g of iodine were added to the solution. The mixture was stirred for 2 hr and then poured into ice water. The reaction product was extracted with an ether, and the extract was well washed with a 10% aqueous solution of sodium thiosulfate and dried over magnesium sulfate. The solvent was removed from the dried reaction product by distillation, and the resultant residue was purified by a silica gel column chromatography through the use of hexane-ethyl acetate as a developing solvent to obtain 31 g of (S)-2,2-diethyl-4-(2-iodoethyl)-1,3-dioxolane. was added to the solution a reaction The resultant reaction mixture the reaction product was extracted with an ether the extract was washed with a saturated saline solution The solvent was distilled off from the extract as washed the resultant residue was purified by a silica gel column chromatography through the use of hexane-ethyl acetate as a developing solvent