Diisopropylethylamine → (9H-fluoren-9-yl)methyl 4-(5-((2S,5R)-6-(benzyloxy)-7-oxo-1,6-diaza-bicyclo[3.2.1]octan-2-yl)-1,2,4-oxadiazol-3-yl)piperidine-1-carboxylate

Participants

Reaction Steps

DIPEA (1.6 mL, 10.0 mmol) was slowly added dropwise to a solution of (2S,5R)-6-(benzyloxy)-2-(3-(piperidin-4-yl)-1,2,4-oxadiazol-5-yl)-1,6-diaza-bicyclo[3.2.1]octan-7-one (1.1 g, 2.0 mmol) in THF (50 mL) at 0° C. The mixture was stiffed under N2 atmosphere at 0° C. for 15 minutes, then, Fmoc-OSu (2.4 g, 7.2 mmol) was added and the mixture was stirred at rt. for 8 hrs. The mixture was concentrated and the residue was purified by silica gel column chromatography (gradient elution 1:6 to 1:2 EtOAc/hexanes) to give (9H-fluoren-9-yl)methyl 4-(5-((2S,5R)-6-(benzyloxy)-7-oxo-1,6-diaza-bicyclo[3.2.1]octan-2-yl)-1,2,4-oxadiazol-3-yl)piperidine-1-carboxylate (1.0 g, 86%) as a white solid.

Provenance & Evidence