1,8-Diazabicyclo(5.4.0)undec-7-ene → Methyl 15-(((benzyloxy)carbonyl)amino)-12-isobutyl-6,11,14-trioxo-1,5,10,13,18,19-hexaazabicyclo[15.2.1]icosa-17(20),18-diene-9-carboxylate

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Reaction Steps

To a solution of compound 10 (0.3 g: 0.512 mmol) in dry DCM (420 mL) under N2 atmosphere, was added DBU (0.233 g; 1.53 mmol) at room temperature with vigorous stirring. After 15 min, Cu(I)Br (0.073 g; 0.512 mmol) was added and the reaction mixture was stirred for 12 h at room temperature. The reaction mixture was quenched by adding 3M HCl (100 mL) and the aqueous layer was separated and extracted with DCM (2×500 mL). The combined organic layers were washed with brine (300 mL), and dried over anhydrous sodium sulfate. The solution was filtered and concentrated to give a crude product which was purified using flash chromatography (silica gel; methylene chloride/methanol 99:1) to give compound 11 as a white solid (0.14 g; 45% yield). 1H NMR (DMSO-d6) δ 8.5 (s, 1H), 8.1 (s, 1H), 7.5 (s, 1H), 7.3 (m, 5H), 5.0 (m, 2H), 4.3 (m, 1H), 4.1 (m, 2H), 3.6 (m, 2H), 3.3 (s, 3H), 3.11 (m, 2H), 2.88 (m, 2H), 2.98-2.24 (m, 5H), 1.49-1.8 (m, 5H), 0.86 (m, 6H).

Provenance & Evidence