1,2-Dibromoethane → 2,2,4-trimethyl-7-(2'-bromo-ethyl-oxy)-(2H)-chromene

Beteiligte Stoffe

Reaktionsschritte

To a 8% aqueous solution of 0.1 mole (19.02 g.) 2,2,4-trimethyl-7-hydroxy-(2H)-chromene and 0.2 mole (8 g.) sodium hydroxide 4 g. of benzene-tributyl-ammonium-chloride as phase transfer catalyst and a solution of 0.2 mole 1,2-dibromo-ethane in 200 ml. methylene-chloride are added under stirring and the solution is heated for 12 hours. After cooling the organic layer is separated and dried above sodium sulphate and evaporated. The residue is dissolved in 50 ml. diethyl-ether and the substance is precipitated by adding 300 ml. of n-hexane. The solvent is decanted from the precipitated substance. Thus 19.38 g. (0.065 mole) product are obtained in the form of a white waxy oily substance.

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