Triethylamine → (R)-1-(4-benzyloxy-3,5-dimethyl-benzyl)-2-(4-benzyl-piperazin-1-yl)-2-oxo-ethyl 4-(2-oxo-1,2,4,5-tetrahydro-1,3-benzodiazepin-3-yl)-piperidine-1-carboxylate

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Reaction Steps

A solution of 1.54 g (2.69 mmol) (R)-2-(4-benzyloxy-3,5-dimethyl-phenyl)-1-carboxy-ethyl 4-(2-oxo-1,2,4,5-tetrahydro-1,3-benzodiazepin-3-yl)-piperidine-1-carboxylate (Example 1g), 952 mg (2.96 mmol) TBTU and 0.47 mL (3.37 mmol) triethylamine in 10 mL THF and 2 mL DMF the mixture was stirred for 1 h at RT. Then 0.52 mL (2.96 mmol) 1-benzyl-piperazine was added and the reaction mixture was stirred for another 14 h at RT. 30 mL EtOAc were added, the organic phase was washed with semisaturated NaHCO3 solution and dried on Na2SO4. After the elimination of the desiccant and solvent the residue was purified by chromatography (silica gel, EtOAc/Cyc 95:5), the fractions containing the product were combined, evaporated down, the residue was triturated with DIPE, suction filtered and dried.

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