Dicyclohexylcarbodiimide → N,N'-Dicyclohexylurea

Beteiligte Stoffe

Reaktionsschritte

1.06 g of a mixture of 80% of EDT-methanol and 20% of hydroxy-PDT (corresponding to 6.19 mmol; 4.95 mmol based on the main component EDT-methanol), 1.04 g (5.04 mmol) of N,N′-dicyclohexylcarbodiimide and 0.15 g (1.22 mmol) of 4-(dimethylamino)pyridine are dissolved in 50 ml of CH2Cl2 and cooled in an ice bath. 1.42 g (5.05 mmol) of [(4′-cyano-1,1′-biphenyl-4-yl)oxy]-butyric acid (see formula) are added in small doses while stirring to the ice-cooled solution. After 1 hour, the reaction is continued at room temperature. After a further 64 hours, the colourless precipitate (N,N′-dicyclohexylurea) formed is filtered off. The clear, colourless solution is washed in succession with 2×75 ml of 1 N HCl, 2×75 ml of saturated NaHCO3 solution and 2×75 ml of NaCl solution. The clear organic phase is dried over MgSO4, the desiccant is filtered off and the solvent is removed on a rotary evaporator. This gives 2.38 g of crude product.

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