Putrescine → 3-Butylcyclohexanone

Beteiligte Stoffe

Reaktionsschritte

To 30 ml of anhydrous diethyl ether were added 1.5 g (10 mmol) of cuprous bromide and 2.5 g (20 mmol) of trimethyl phosphite, and the mixture stirred for about 1 hour at room temperature in an atmosphere of nitrogen. The mixture was cooled to -78° C, and 12.8 ml (20 mmol) of a 15 % by weight hexane solution of n-butyllithium was added, followed by further stirring the mixture for 30 minutes. Then, 960 mg (10 mmol) of 2-cycohexenone was added and reacted for 1 hour. After the reaction, 5 ml of tetramethylenediamine was added, and the mixture was stirred for about 10 minutes. The resulting solution was added dropwise at 0° C to a solution prepared by adding 2.84 g (20 mmol) of a boron trifluoride-diethyl ether complex and 2.04 g (20 mmol) of acetic anhydride to 20 ml of anhydrous diethyl ether, and stirring the mixture at 0° C for about 30 minutes in an atmosphere of nitrogen. Then, the mixture was stirred for an additional 3 hours at room temperature, and then, post-treated, extracted, washed with dilute hydrochloric acid, and dried in the same way as in Example 4 to afford 5.432 g of a crude product. The crude product was purified by distillation at reduced pressure to afford 370 mg (2.4 mmol) of 3-n-butylcyclohexanone in a yield of 24% and 170 mg (0.9 mmol) of 2-acetyl-3-n-butylcyclohexanone in a yield of 9%.

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