Piperidine → 3-[4-(2-chlorophenyl)-6,9-dimethyl-6H-thieno[3,2-f][1,2,4]triazolo[4,3-a][1,4]diazepin-2-yl]propionic acid piperidide

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Reaction Steps

To a solution of 1.1 g of 3-[4-(2-chlorophenyl)-6,9-dimethyl-6H-thieno[3,2-f][1,2,4]triazolo[4,3-a][1,4]diazepin-2-yl]propionic acid in 15 ml of dimethylformamide are added 0.4 g of N-hydroxybenzotriazole and 0.25 g of piperidine and stirred at room temperature for 10 minutes. To the mixture is added 0.65 g of dicyclohexyl carbodiimide under ice-cooling and stirred for 1 hour and furthermore stirred at room temperature for 20 hours. The resulting dicyclohexylurea is filtered off and to the filtrate is added 50 ml of chloroform. The solution is washed with 5% aqueous sodium hydrogencarbonate solution and water and dried over anhydrous magnesium sulfate. After separating by filtration, the filtrate is concentrated under reduced pressure and the residue is crystallized from ethyl acetate. The precipitated crystals are collected by filtration and recrystallized from ethyl acetate to give 0.9 g of 3-[4-(2-chlorophenyl)-6,9-dimethyl-6H-thieno[3,2-f][1,2,4 ]triazolo[4,3-a][1,4]diazepin-2-yl]propionic acid piperidide as colorless crystals, melting at 157°-160° C.

Provenance & Evidence