Dicyclohexylcarbodiimide → 1-[1-oxo-2-(4-Nitro-1H-imidazol-1-yl)octyl]-L-proline benzyl ester

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Reaction Steps

Diisopropylethylamine (39.6 mmoles, 5.1 g) was added to a solution of L-proline benzyl ester hydrochloride (39.6 mmoles, 10.1 g) in 20 ml DMF at 0° and stirred for 1 hour. The solution was added to 2-(4-nitro-1H-imidazol-1-yl) octanoic acid (39.6 mmoles, 10.1 g) and hydroxybenzotriazole (43 mmoles, 5.8 g) in 10 ml DMF, and stirred for 30 minutes. Dicyclohexylcarbodiimide (43 mmoles, 8.97 g) was added portionwise over 2 hours. Ethyl acetate (50 ml) was added. The solution was filtered, dried over sodium sulfate and concentrated. The oil was chromatographed over silica gel eluted with 40% ethyl acetate in hexane to yield 5.32 g of 1-[1-oxo-2-(4-Nitro-1H-imidazol-1-yl)octyl]-L-proline benzyl ester.

Provenance & Evidence