5-Chloro-salicylaldehyde → 5-Chloro-2-(4-chloro-trans-2-butenyloxy)-benzaldehyde

Beteiligte Stoffe

Reaktionsschritte

To 1.2 lt of refluxing water, 1 ml of 40% aqueous tetrabutylammonium hydroxide, 160 g of 5-chloro-salicylaldehyde and 140 ml of trans-1,4-dichloro-2-butene are added while vigorously stirring, followed by the dropwise addition of the solution of 42 g of sodium hydroxide in 200 ml of water at such a rate that the pH of the mixture is kept between 7 and 8. Thereafter the mixture is refluxed until the pH is about 7, cooled and extracted with methylene chloride. The extract is washed with 5% aqueous sodium hydroxide, dried, evaporated and the residue heated to 30°/0.1 mmHg in order to remove the excess of 1,4-dichloro-2-butene. The residue is taken up in 1 lt of diethyl ether, the solution filtered, the filtrate evaporated and the residue recrystallized from ethyl acetate, to yield the 5-chloro-2-(4-chloro-trans-2-butenyloxy)-benzaldehyde melting at 62°-63°.

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