4-Methylmorpholine → (S)-2-[(S)-4-benzyloxycarbonyl-2-(1,3-dioxo-1,3-dihydro-isoindol-2-yl)-butyryl]-3-phenethylcarbamoyl-tetrahydro-pyridazine-1-carboxylic acid benzyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of (S)-2-(1,3-dioxo-1,3-dihydro-isoindol-2-yl)-pentanedioic acid 5-benzyl ester (580 mg, 1.59 mmol) in ether (25 mL) at 0° C., is added PCl5 (920 mg, 4.38 mmol) in one portion. After stirring at 25° C. for 40 minutes, ether is removed by evaporation, and the residue is dissolved in 20 mL of THF, and is added to a solution of (S)-3-phenethylcarbamoyl-tetrahydro-pyridazine-1-carboxylic acid benzyl ester (580 mg) and N-methylmorpholine (0.74 mL, 6.77 mmol) in THF (10 mL) at 0° C. slowly. After stirring at room temperature for 2 hours, the reaction mixture is diluted with 100 mL of ether and washed with 2×20 mL of water. The combined organic layers is dried over Na2SO4 and concentrated, and purified by chromatography (CH2Cl2/MeOH:97/3) to give (S)-2-[(S)-4-benzyloxycarbonyl-2-(1,3-dioxo-1,3-dihydro-isoindol-2-yl)-butyryl]-3-phenethylcarbamoyl-tetrahydro-pyridazine-1-carboxylic acid benzyl ester (1.13 g, 99.2%) as pale solid. (NMR and MS data confirmed, U-3133-62).

Provenance & Evidence