(4S)-4,8-dimethyl-7-nonen-2-ol → (4S)-4,8-dimethyl-7-nonen-2-one

Beteiligte Stoffe

Reaktionsschritte

Acetone (2,000 ml) and the (4S)-4,8-dimethyl-7-nonen-2-ol (240 g) synthesized in Reference Example 1 were placed in a 5-liter, 4-necked flask equipped with a dropping funnel, thermometer, condenser and stirrer. Jones reagent (prepared from water (520 ml), conc. sulfuric acid (165 g) and chromium trioxide (112 g)) placed in the dropping funnel was dropped in over the course of 4 hours while cooling with ice. After the dropwise addition, the mixture was stirred for 2 hours. The sodium hydrogen sulfite was added little by little until the orange color of chromium (VI) disappeared. The liquid was then separated and the bottom layer was extracted with petroleum ether (1,000 ml). Since the liquid was again separated into two layers when the extract was combined with the top layer, that bottom layer was added to the previous bottom layer and additionally extracted three times with 500 ml of petroleum ether. After combining the extracts and washing with a saturated brine, a saturated aqueous sodium hydrogencarbonate solution and again with a saturated brine, the solvent was distilled off and the resulting concentrated oil was distilled with a Widmer distiller to obtain 194 g of (4S)-4,8-dimethyl-7-nonen-2-one: (4S)-(14) (b.p.: 63° C./133 Pa (1.0 torr)).

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