4-氧代戊基乙酸酯

反应条件: temp:0.00; pressure:0.00; stir:

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

实验步骤: Potassium tert-butoxide (9.4 g, 84 mmol) was added to a mixture of methyltriphenylphosphonium bromide (30 g, 84 mmol) in THF (300 ml), and the mixture was stirred at room temperature for 40 minutes. To the mixture a solution of 4-oxopentyl acetate (9.9 g, 68.8 mmol) in THF (30 ml) was gradually added dropwise while cooling in an ice-bath, and the mixture was stirred at room temperature for 2 hours. The reaction mixture was poured into ice water, and extracted with diethyl ether twice. The extracts were combined, washed with brine, and dried over magnesium sulfate. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography (n-hexane/ethyl acetate=4/1) to afford 4-methyl-4-pentenyl acetate (5.9 g, yield 60.4%) as a colorless oil. while cooling in an ice-bath the mixture was stirred at room temperature for 2 hours extracted with diethyl ether twice washed with brine dried over magnesium sulfate After filtration the filtrate was concentrated under reduced pressure The residue was purified by silica gel column chromatography (n-hexane/ethyl acetate=4/1)

反应条件: temp:0.00; pressure:0.00; stir:

反应条件: temp:40.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a 1 liter 3-neck round bottom flask equipped with a stirrer, thermometer, condenser and addition funnel, was added 102 grams (1 mole) of 3-acetylpropanol, 125 mls of pyridine and 600 mls of methylene chloride. With ice cooling and good agitation, 78.5 grams (1 mole) of acetyl chloride was added slowly from the addition funnel while holding the temperature at 25° C. or below. Pyridine hydrochloride began coming out of solution about 1/3 of the way through the addition. After the addition was complete, the reaction mixture was stirred an additional 15 minutes at 20°-25° C. and then warmed to 40° C. and stirred an hour at 40° C. Then 150 mls of water were added to dissolve the pyridine hydrochloride and the aqueous layer was separated. The organic layer was washed twice with 200 mls of 10% HCl, once with water and saturated sodium bicarbonate solution. The organic layer was dried over anhydrous sodium sulfate, filtered and the methylene chloride stripped off on a rotary evaporator under reduced pressure. The light yellow liquid weighed 104 grams (72% crude yield). The infrared spectrum of the product contained two strong carbonyl bands at 1720 cm-1 and 1745cm-1 and there was no OH band. To a 1 liter 3-neck round bottom flask equipped with a stirrer thermometer, condenser and addition funnel at 25° C. or below After the addition stirred an hour at 40° C the aqueous layer was separated The organic layer was washed twice with 200 mls of 10% HCl, once with water and saturated sodium bicarbonate solution The organic layer was dried over anhydrous sodium sulfate filtered the methylene chloride stripped off on a rotary evaporator under reduced pressure

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

实验步骤: A mixture of 0.5 moles of 1-acetoxypentan-4-one and 0.5 moles of piperidine in benzene is refluxed using a water separator until no more water distills from the reaction mixture. The reaction mixture is then cooled, washed and dried to afford the 4-piperidyl-1-acetoxypent-3-ene (XIX). A mixture of 5 g. of XIX in 100 ml. of dioxane is treated with an excess of methyl iodide at 20°C for 18 hours and then heated at 70°C for 6 hours. The reaction mixture is concentrated to a small volume, diluted with water and 1-acetoxy-3-methylpentan-4-one isolated by extraction with ethyl acetate. A mixture of 0.5 g. of this ketone, 100 mg. of p-toluenesulfonic acid, 3 ml. of ethyleneglycol and 100 ml. of benzene is refluxed using a water separator for 24 hours. The reaction mixture is cooled and then 100 ml. of ethanol and 2 g. of potassium hydroxide are added. This mixture is refluxed for 6 hours, cooled, diluted with water and the corresponding ethylene ketal is isolated by extraction with ethyl acetate. A solution of 0.1 moles of the ketal in 50 ml. of dimethylformamide containing 0.1 moles of triphenylphosphine is reacted with 0.1 moles of carbon tetrabromide at room temperature for 18 hours. The mixture is diluted with water and extracted with ether. The ether extracts are combined, washed with water, dried and evaporated. The residue is chromatographed on 400 g. of alumina eluting with hexane-benzene and benzene to give the ethylene ketal of 1-bromo-3-methylpentan-4-one. ##EQU16## is refluxed distills from the reaction mixture The reaction mixture is then cooled washed dried

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

实验步骤: Potassium tert-butoxide (9.4 g, 84 mmol) was added to a mixture of methyltriphenylphosphonium bromide (30 g, 84 mmol) in THF (300 ml), and the mixture was stirred at room temperature for 40 minutes. To the mixture a solution of 4-oxopentyl acetate (9.9 g, 68.8 mmol) in THF (30 ml) was gradually added dropwise while cooling in an ice-bath, and the mixture was stirred at room temperature for 2 hours. The reaction mixture was poured into ice water, and extracted with diethyl ether twice. The extracts were combined, washed with brine, and dried over magnesium sulfate. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography (n-hexane/ethyl acetate=4/1) to afford 4-methyl-4-pentenyl acetate (5.9 g, yield 60.4%) as a colorless oil. while cooling in an ice-bath the mixture was stirred at room temperature for 2 hours extracted with diethyl ether twice washed with brine dried over magnesium sulfate After filtration the filtrate was concentrated under reduced pressure The residue was purified by silica gel column chromatography (n-hexane/ethyl acetate=4/1)