Dicyclohexylcarbodiimide → N,N'-Dicyclohexylurea

Beteiligte Stoffe

Reaktionsschritte

3.26 g of a mixture of 80% of EDT-methanol and 20% of hydroxy-PDT (corresponding to 18.9 mmol; 15.1 mmol based on the main component EDT-methanol), 3.14 g (15.2 mmol) of N,N′-dicyclohexylcarbodiimide and 0.3 g (2.45 mmol) of 4-(dimethylamino)pyridine are dissolved in 100 ml of CH2Cl2 and cooled in an ice bath. 5.25 g (15.0 mmol) of [(4′-bromo-1,1′-biphenyl-4-yl)oxy]-valeric acid are added a spatula at a time to the ice-cooled solution while stirring. After 1 hour, the reaction is continued at room temperature. After a further 65 hours, the colourless precipitate formed (N,N′-dicyclohexylurea) is filtered off. The clear, colourless solution is washed in succession with 3×250 ml of 1 N HCl, 3×150 ml of saturated NaHCO3 solution and 1×150 ml and 2×100 ml of saturated NaCl solution. The organic phase is dried over MgSO4, the desiccant is filtered off and the solvent is removed on a rotary evaporator. This gives 7.98 g of crude product.

Herkunft & Nachweise