Dicyclohexylcarbodiimide → N,N'-Dicyclohexylurea

Beteiligte Stoffe

Reaktionsschritte

A portion (10.3g= 0.05 mole) of dicyclohexylcarbodiimide (DCC) was added dropwise under stirring at 0° C. to a solution of N-Boc-glycyl-L-proline prepared in accordance with the method described in J. Chem. Soc. (C), 954 (1969) (27.2g= 0.1 mole) in dried THF (100ml) and the reaction mixture was kept under continuous stirring for 45 minutes. To the filtrate obtained by filtering-off of dicyclohexyl urea precipitated in the mixture, was added at 0° C. a solution of 7-amino-4-methylcoumarin (8.75g= 0.05 mole) in dimethylformamide (DMF) (60ml). After standing overnight at room temperature, the reaction mixture was concentrated in vacuo to give a residue which was dissolved in ethyl acetate (300ml.). The solution was washed successively with 1 N hydrochloric acid, aqueous 5% sodium bicarbonate and water, dried with anhydrous magnesium sulfate, and concentrated in vacuo. The residue was recrystallized from a binary mixture of ethyl acetate (150ml) and n-hexance (70ml) to give 20.1g (yield, 93.4%) of crystalline 7-(n-BOC-glycyl-L-prolyl)-amino-4-methylcoumarin.

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