Hydrochloric Acid → 3-Nonen-5-ol, 4,8-dimethyl-

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Reaction Conditions

Reaction Steps

69.5 g (2.9 g atoms) of magnesium are placed in 500 ml of absolute ether. Subsequently, a solution of 438 g of isoamyl bromide, which contains ca 1.5% n-amyl bromide in accordance with gas chromatography, in 1.2 l of absolute ether is added dropwise so that the exothermic reaction maintains the ether constantly at the boiling point. After completing the addition, the mixture is held at reflux temperature for a further 30 minutes. The Grignard solution is thereupon cooled to 10° C. Then, 236.5 g (2.41 mol) of 2-methyl-2-pentenal in 600 ml of absolute ether are added dropwise within 40 minutes, the temperature being held between 10° and 20° C. during the addition. In order to complete the reaction, the mixture is held at reflux temperature for a further 1 hour. The mixture is subsequently added to ice, decomposed with aqueous hydrochloric acid, the ethereal solution is washed neutral with sodium carbonate solution and saturated sodium chloride solution and then dried. The crude product (480 g) remaining after distillation of the solvent is fractionally distilled over a Widmer column and gives 312 g of 2,6-dimethyl-6-nonen-5-ol (III) of boiling point 62° C./0.05 mm Hg; nD25 =1.4479, which contains 1.5% of 4-methyl-3-decen-5-ol in accordance with gas chromatography (Carbowax, 130° C.).

Provenance & Evidence