benzyl (2R)-2-hydroxy-4-methylpentanoate

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

Procedure: To 150 ml of tetrahydrofurane of 14.50 of D-leucic acid, 15.2 g of triethylamine and then 14.4 ml of benzyl bromide are added, and the solution was stirred for 3 hours while refluxing. The insoluble matter produced from the reaction solution was filtered off, and the filtrate was concentrated in vacuo. The obtained residue was dissolved and extracted in 150 ml of ethyl acetate. The ethyl acetate layer was washed twice with saturated bicarbonate water, twice with 1N hydrochloric acid, and twice with saturated brine sequentially, and dried over sodium sulfate anhydride, and concentrated in vacuo. The obtained oily residue was dried, and the captioned compound was obtained. Yield: 18.34 g. while refluxing The insoluble matter produced from the reaction solution was filtered off the filtrate was concentrated in vacuo The obtained residue was dissolved extracted in 150 ml of ethyl acetate The ethyl acetate layer was washed twice with saturated bicarbonate water, twice with 1N hydrochloric acid twice with saturated brine sequentially, and dried over sodium sulfate anhydride concentrated in vacuo The obtained oily residue was dried the captioned compound was obtained

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

Procedure: 264.0 g. of (R)-2-hydroxy-isocaproic acid were dissolved in 1.8 litres of absolute dioxan in a three-necked flask fitted with a stirrer, thermometer annd reflux condenser with a calcium chloride tube. The solution was treated successively with 285 ml. of triethylamine and 236 ml. of benzyl chloride and heated at an internal temperature of 100° for 20 hours with stirring in an oil-bath. After cooling, the resulting triethylamine hydrochloride was filtered off and washed with 500 ml. of ethyl acetate. The filtrate was evaporated under reduced pressure at 50°. The residual oil was dissolved in 800 ml. of ethyl acetate and washed twice with 150 ml. portions of 3-N hydrochloric acid, twice with 100 ml. portions of 5% sodium chloride solution, twice with 150 ml. portions of 10% potassium bicarbonate solution and twice with 100 ml. portions of 5% sodium chloride solution. After each of these washings, the oil was rinsed with 200 ml. of ethyl acetate. The ethyl acetate solutions were dried over magnesium sulphate and evaporated under reduced pressure at 50°. The crude product which was thus-obtained was distilled at 0.3 Torr (112°-115°). There was obtained benzyl-(R)-2-hydroxyisocaproate; [α]D25 = + 18.0° (c = 1 in methanol); nD23 = 1.498. fitted with a stirrer The solution was treated successively with 285 ml After cooling the resulting triethylamine hydrochloride was filtered off washed with 500 ml The filtrate was evaporated under reduced pressure at 50° The residual oil was dissolved in 800 ml of ethyl acetate and washed twice with 150 ml After each of these washings, the oil was rinsed with 200 ml The ethyl acetate solutions were dried over magnesium sulphate evaporated under reduced pressure at 50° The crude product which was thus-obtained was distilled at 0.3 Torr (112°-115°)

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

Procedure: 264.0 g of (R)-2-hydroxy-isocaproic acid were dissolved in 1.8 liters of absolute dioxan in a three-necked flask fitted with a stirrer, thermometer and reflux condenser with a calcium chloride tube. The solution was treated successively with 285 ml. of triethylamine and 236 ml. of benzyl chloride and heated at an internal temperature of 100° for 20 hours with stirring in an oil-bath. After cooling, the resulting triethylamine hydrochloride was filtered off and washed with 500 ml. of ethyl acetate. The filtrate was evaporated under reduced pressure at 50°. The residual oil was dissolved in 800 ml. of ethyl acetate and washed twice with 150 ml. portions of 3-N hydrochloric acid, twice with 100 ml. portions of 5% sodium chloride solution, twice with 150 ml. portions of 10% potassium bicarbonate solution and twice with 100 ml. portions of 5% sodium chloride solution. After each of these washings, the oil was rinsed with 200 ml. of ethyl acetate. The ethyl acetate solutions were dried over magnesium sulphate and evaporated under reduced pressure at 50°. The crude product which was thus-obtained was distilled at 0.3 Torr (112°-115°). There was obtained benzyl-(R)-2-hydroxyisocaproate; [α]D25 =+18.0° (c = 1 in methanol); nD23 = 1.498. fitted with a stirrer thermometer and reflux condenser with a calcium chloride tube The solution was treated successively with 285 ml After cooling the resulting triethylamine hydrochloride was filtered off washed with 500 ml The filtrate was evaporated under reduced pressure at 50° The residual oil was dissolved in 800 ml of ethyl acetate and washed twice with 150 ml After each of these washings, the oil was rinsed with 200 ml The ethyl acetate solutions were dried over magnesium sulphate evaporated under reduced pressure at 50° The crude product which was thus-obtained was distilled at 0.3 Torr (112°-115°)

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

Procedure: To 150 ml of tetrahydrofurane of 14.50 of D-leucic acid, 15.2 g of triethylamine and then 14.4 ml of benzyl bromide are added, and the solution was stirred for 3 hours while refluxing. The insoluble matter produced from the reaction solution was filtered off, and the filtrate was concentrated in vacuo. The obtained residue was dissolved and extracted in 150 ml of ethyl acetate. The ethyl acetate layer was washed twice with saturated bicarbonate water, twice with 1N hydrochloric acid, and twice with saturated brine sequentially, and dried over sodium sulfate anhydride, and concentrated in vacuo. The obtained oily residue was dried, and the captioned compound was obtained. Yield: 18.34 g. while refluxing The insoluble matter produced from the reaction solution was filtered off the filtrate was concentrated in vacuo The obtained residue was dissolved extracted in 150 ml of ethyl acetate The ethyl acetate layer was washed twice with saturated bicarbonate water, twice with 1N hydrochloric acid twice with saturated brine sequentially, and dried over sodium sulfate anhydride concentrated in vacuo The obtained oily residue was dried the captioned compound was obtained

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

Procedure: A mixture of 2.05 g of 2-(R)-hydroxy-4-methylpentanoic acid, 2.01 g of benzyl alcohol and 0.251 g of p-toluenesulfonic acid monohydrate in 40 ml of benzene was heated to reflux for 1.5 hours. The reaction mixture, after being allowed to cool, was washed with a saturated aqueous solution of sodium bicarbonate and brine, and then dried over anhydrous magnesium sulfate. Then the solvent was distilled off under reduced pressure to yield the title compound as a colorless oil (2.30 g). was heated to reflux for 1.5 hours to cool was washed with a saturated aqueous solution of sodium bicarbonate and brine dried over anhydrous magnesium sulfate Then the solvent was distilled off under reduced pressure

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

Procedure: 278 g of benzyl bromide were added to a stirred solution of 215 g of D-leucic acid and 246 g of triethylamine in 2.5 l of ethy acetate. The mixture was then heated under reflux for 5 hours, cooled and filtered to remove triethylamine hydrobromide. The filtrate was washed twice with 2M hydrochloric acid, water, saturated sodium bicarbonate solution and then saturated sodium chloride solution. The organic extract was dried over magnesium sulfate and evaporated to give 225 g of D-leucic acid benzyl ester as a yellow liquid. The mixture was then heated under reflux for 5 hours cooled filtered to remove triethylamine hydrobromide The filtrate was washed twice with 2M hydrochloric acid, water, saturated sodium bicarbonate solution The organic extract was dried over magnesium sulfate evaporated

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

Procedure: 264.0 g. of (R)-2-hydoxy-isocaproic acid were dissolved in 1.8 liters of absolute dioxan in a three-necked flask fitted with a stirrer, thermometer and reflux condenser with a calcium chloride tube. The solution was treated successively with 285 ml. of triethylamine and 236 ml. of benzyl chloride and heated at an internal temperature of 100° for 20 hours with stirring in an oil-bath. After cooling, the resulting triethylamine hydrochloride was filtered off and washed with 500 ml. of ethyl acetate. The filtrate was evaporated under reduced pressure at 50°. The residual oil was dissolved in 800 ml. of ethyl acetate and washed twice with 150 ml. portions of 3-N hydrochloric acid, twice with 100 ml. portions of 5 percent sodium chloride solution, twice with 150 ml. portions of 10 percent potassium bicarbonate solution and twice with 100 ml. portions of 5 percent sodium chloride solution. After each of these washings, the oil was rinsed with 200 ml. of ethyl acetate. The ethyl acetate solutions were dried over magnesium sulphate and evaporated under reduced pressure at 50°. The crude product which was thus-obtained was distilled at 0.3 Torr (112°-115°). There was obtained benzyl-(R)-2-hydroxy-isocaproate; [α]D25 = + 18.0° (c = 1 in methanol); nD23 = 1.498. fitted with a stirrer thermometer and reflux condenser with a calcium chloride tube The solution was treated successively with 285 ml After cooling the resulting triethylamine hydrochloride was filtered off washed with 500 ml The filtrate was evaporated under reduced pressure at 50° The residual oil was dissolved in 800 ml of ethyl acetate and washed twice with 150 ml After each of these washings, the oil was rinsed with 200 ml The ethyl acetate solutions were dried over magnesium sulphate evaporated under reduced pressure at 50° The crude product which was thus-obtained was distilled at 0.3 Torr (112°-115°)

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

Procedure: 264.0 g. of (R)-2-hydroxy-isocaproic acid were dissolved in 1.8 litres of absolute dioxan in a three-necked flask fitted with a stirrer, thermometer annd reflux condenser with a calcium chloride tube. The solution was treated successively with 285 ml. of triethylamine and 236 ml. of benzyl chloride and heated at an internal temperature of 100° for 20 hours with stirring in an oil-bath. After cooling, the resulting triethylamine hydrochloride was filtered off and washed with 500 ml. of ethyl acetate. The filtrate was evaporated under reduced pressure at 50°. The residual oil was dissolved in 800 ml. of ethyl acetate and washed twice with 150 ml. portions of 3-N hydrochloric acid, twice with 100 ml. portions of 5% sodium chloride solution, twice with 150 ml. portions of 10% potassium bicarbonate solution and twice with 100 ml. portions of 5% sodium chloride solution. After each of these washings, the oil was rinsed with 200 ml. of ethyl acetate. The ethyl acetate solutions were dried over magnesium sulphate and evaporated under reduced pressure at 50°. The crude product which was thus-obtained was distilled at 0.3 Torr (112°-115°). There was obtained benzyl-(R)-2-hydroxyisocaproate; [α]D25 = + 18.0° (c = 1 in methanol); nD23 = 1.498. fitted with a stirrer The solution was treated successively with 285 ml After cooling the resulting triethylamine hydrochloride was filtered off washed with 500 ml The filtrate was evaporated under reduced pressure at 50° The residual oil was dissolved in 800 ml of ethyl acetate and washed twice with 150 ml After each of these washings, the oil was rinsed with 200 ml The ethyl acetate solutions were dried over magnesium sulphate evaporated under reduced pressure at 50° The crude product which was thus-obtained was distilled at 0.3 Torr (112°-115°)

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

Procedure: 264.0 g of (R)-2-hydroxy-isocaproic acid were dissolved in 1.8 liters of absolute dioxan in a three-necked flask fitted with a stirrer, thermometer and reflux condenser with a calcium chloride tube. The solution was treated successively with 285 ml. of triethylamine and 236 ml. of benzyl chloride and heated at an internal temperature of 100° for 20 hours with stirring in an oil-bath. After cooling, the resulting triethylamine hydrochloride was filtered off and washed with 500 ml. of ethyl acetate. The filtrate was evaporated under reduced pressure at 50°. The residual oil was dissolved in 800 ml. of ethyl acetate and washed twice with 150 ml. portions of 3-N hydrochloric acid, twice with 100 ml. portions of 5% sodium chloride solution, twice with 150 ml. portions of 10% potassium bicarbonate solution and twice with 100 ml. portions of 5% sodium chloride solution. After each of these washings, the oil was rinsed with 200 ml. of ethyl acetate. The ethyl acetate solutions were dried over magnesium sulphate and evaporated under reduced pressure at 50°. The crude product which was thus-obtained was distilled at 0.3 Torr (112°-115°). There was obtained benzyl-(R)-2-hydroxyisocaproate; [α]D25 =+18.0° (c = 1 in methanol); nD23 = 1.498. fitted with a stirrer thermometer and reflux condenser with a calcium chloride tube The solution was treated successively with 285 ml After cooling the resulting triethylamine hydrochloride was filtered off washed with 500 ml The filtrate was evaporated under reduced pressure at 50° The residual oil was dissolved in 800 ml of ethyl acetate and washed twice with 150 ml After each of these washings, the oil was rinsed with 200 ml The ethyl acetate solutions were dried over magnesium sulphate evaporated under reduced pressure at 50° The crude product which was thus-obtained was distilled at 0.3 Torr (112°-115°)

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

Procedure: To 150 ml of tetrahydrofurane of 14.50 of D-leucic acid, 15.2 g of triethylamine and then 14.4 ml of benzyl bromide are added, and the solution was stirred for 3 hours while refluxing. The insoluble matter produced from the reaction solution was filtered off, and the filtrate was concentrated in vacuo. The obtained residue was dissolved and extracted in 150 ml of ethyl acetate. The ethyl acetate layer was washed twice with saturated bicarbonate water, twice with 1N hydrochloric acid, and twice with saturated brine sequentially, and dried over sodium sulfate anhydride, and concentrated in vacuo. The obtained oily residue was dried, and the captioned compound was obtained. Yield: 18.34 g. while refluxing The insoluble matter produced from the reaction solution was filtered off the filtrate was concentrated in vacuo The obtained residue was dissolved extracted in 150 ml of ethyl acetate The ethyl acetate layer was washed twice with saturated bicarbonate water, twice with 1N hydrochloric acid twice with saturated brine sequentially, and dried over sodium sulfate anhydride concentrated in vacuo The obtained oily residue was dried the captioned compound was obtained