4-Methylmorpholine → Methyl N2-(tert-butoxycarbonyl)-N5,N5-bis(2-((tert-butoxycarbonyl)amino)ethyl)-L-glutaminate

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Reaction Steps

To a solution of CDMT (2.22 g, 12.62 mmol) in DCM (40 mL) and cooled to 0° C. was added N-methylmorpholine (1.38 mL, 12.63 mmol). The mixture was stirred for 10 min before adding (4S)-4-{[(tert-butoxy)carbonyl]amino}-5-methoxy-5-oxopentanoic acid (3.0 g, 11.48 mmol). The solution was stirred for 60 min at 0° C. The tert-butyl N-{2-[(2-{[(tert-butoxy)carbonyl]amino}ethyl)amino]ethyl}carbamate XIV was then added and the mixture stirred at room temperature overnight. The solution was washed with 1 M aq. K2CO3, 1 M aq. HCl, brine and dried over anhydrous MgSO4. The crude product was crystallized from DCM/hexane to give methyl (2S)-4-[bis(2-{[(tert-butoxy)carbonyl]amino}ethyl)carbamoyl]-2-{[(tert-butoxy)carbonyl]amino}butanoate (XV) (4.91 g, 8.98 mmol, 72% yield). 1H NMR (DMSO-d6) δ ppm 1.35-1.47 (m, 27H), 1.80-1.91 (m, 1H), 2.19-2.32 (m, 1H), 2.33-2.42 (m, 1H), 2.46-2.57 (m, 1H), 3.11-3.38 (m, 6H), 3.40-3.53 (m, 1H), 3.54-3.62 (m, 1H), 3.73 (s, 3H), 4.26-4.38 (m, 1H), 4.99-5.09 (brs, 1H), 5.31-5.46 (m, 2H); ESIMS found for C25H46N4O9 m/z 547 (M+H).

Provenance & Evidence