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 Synthesis of 1-(Hydroxymethyl)cyclohexanol
  • Synthesis of 1-(Hydroxymethyl)cyclohexanol
  • 1-(Hydroxymethyl)cyclohexanol (CAS no.: ), which is also known as methanol, 1-hydroxy-, could be produced through the following synthetic routes.

    A. 1-[(Isopropoxydimethylsilyl)methyl]cyclohexanol. A 500-mL, three-necked flask is equipped with a pressure-equalizing dropping funnel, a magnetic stirrer, a three-way stopcock, and a reflux condenser connected with a nitrogen bubbler. The flask is charged with magnesium turnings (2.43 g, 100 mg-atm) that are dried under a rapid stream of nitrogen with a heat gun. After the flask is cooled to room temperature, the rate of nitrogen flow is reduced. Several milliliters of a solution of (isopropoxydimethylsilyl)methyl chloride (16.67 g, 100 mmol) in dry tetrahydrofuran (THF) (120 mL) and about 50 μL of 1,2-dibromoethane are added. The mixture is stirred at room temperature and within a few minutes an exothermic reaction starts. The remaining solution is added dropwise at room temperature over ca. 45 min at such a rate as to maintain a gently exothermic reaction. After the addition is complete, the tan-gray mixture is refluxed for 0.5 hr and then cooled to 0°C with an ice bath. A solution of freshly distilled cyclohexanone (7.36 g, 75 mmol) in dry THF (30 mL) is added dropwise with stirring over 30 min. The resultant mixture is stirred at 0°C for another 30 min and then hydrolyzed by dropwise addition of an aqueous 10% solution of ammonium chloride (100 mL) at 0°C over 10 min. The organic layer is separated. The aqueous layer is extracted with four 40-mL portions of diethyl ether. The combined organic layer and extracts are washed once with aqueous saturated sodium chloride, dried over magnesium sulfate, filtered into a 500-mL round-bottomed flask and concentrated with a rotary evaporator below room temperature at water aspirator pressure. A colorless oil remains.

    B. 1-(Hydroxymethyl)cyclohexanol The 500-mL, round-bottomed flask containing the crude 1-[(isopropoxydimethylsilyl)methyl]cyclohexanol is equipped with a magnetic stirrer and a thermometer, and is kept open to air throughout the reaction. The flask is charged with tetrahydrofuran (75 mL), methanol (75 mL), potassium hydrogen carbonate (7.5 g 75 mmol), and potassium fluoride (8.7 g, 150 mmol). To the stirred mixture is added 30% hydrogen peroxide (28.0 mL, 247.5 mmol) in one portion at room temperature. A somewhat cloudy organic layer and a milky-white, heavy inorganic layer result. After several minutes an exothermic reaction begins which is controlled by intermittent, brief cooling with a water bath to maintain the temperature at 40–50°C. After about 30 min the exothermic reaction ceases. The mixture is then stirred at room temperature for 2 hr. The remaining hydrogen peroxide is decomposed by careful dropwise addition of an aqueous 50% solution of sodium thiosulfate pentahydrate (ca. 30 mL) with stirring over 30 min, during which time the temperature is maintained near 30°C by intermittent cooling with an ice bath. A negative starch-iodide test is observed. A white precipitate forms and diethyl ether (ca. 100 mL) is added to ensure further precipitation. The mixture is filtered with suction and the filter cake is washed with three 20-mL portions of diethyl ether. The combined filtrate and washes are concentrated with a rotary evaporator at 50°C at water aspirator pressure until much of the water has been removed. The remaining oil is diluted with diethyl ether (ca. 200 mL), transferred to a separatory funnel, and washed with saturated aqueous sodium chloride solution to remove the remaining water. The organic layer is separated, dried over magnesium sulfate, filtered, and concentrated with a rotary evaporator to give a colorless solid. The solid is dissolved in a 10 : 1 mixture of hexane–ethyl acetate (75 mL) at reflux, and the hot solution is filtered. The filtrate is allowed to cool to room temperature and finally is kept at 0°C for 2 hr. The crystals are separated with suction, washed with cold hexane/ethyl acetate (10 : 1, 10 mL), and dried under high vacuum at room temperature. There is obtained 7.54 g (77%) of 1-(hydroxymethyl)cyclohexanol as white crystals, mp 76.0–76.2°C.


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