Cyclohexane → 1,2,3,4,4a,5,6,7,8,9a-Decahydrofluoren-9-one

Beteiligte Stoffe

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Reaktionsschritte

In a 250 ml three neck round bottom flask, equipped with a mechanical stirrer, a thermometer and a reflux condenser 16.276 g of polyphosphoric acid was charged and heated to a temperature of 70° C. 16.276 g of 1-cyclohexenecarboxylic acid and 10.592 g of cyclohexane were added dropwise maintaining a temperature of the reaction mass below 100° C. The mixture was stirred at 78° C. for additional 4.5 hours. The dark brown reaction mass was was poured onto 237 g of ice and neutralised with 89 g aqueous ammonium sulphate solution in 474 g of water. The resulting mixture was then extracted 4 times with 300 ml of petroleum ether and 300 ml of diethyl ether. All organic layers were combined, washed successively with 5% aqueous ammonium hydroxide, brine dried over magnesium sulphate and concentrated in vacuum. Fractional distillation (b.p. 130° C. at 3.0 mmHg) of this crude product yielded 10.294 g of 1,2,3,4,4a,5,6,7,8,9a-decahydro-9H-fluoren-9-one. 1H-NMR (CDCl3): δ 2.73 (q, J=7 Hz, 1 H), 2.2–0.5 (m, 17 H).

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