Cesium carbonate → HCID 131736368, compound

Participants

Reaction Conditions

Reaction Steps

Cs2CO3 (331 mg, 1.01 mmol, Eq: 2.2) was added was added to a solution of tert-butyl methyl((S)-1-oxo-1-((S)-4-oxo-2′,3′,4,5,5′,6′-hexahydro-3H-spiro[benzo[b][1,4]oxazepine-2,4′-pyran]-3-ylamino)propan-2-yl)carbamate (200 mg, 461 μmol, Eq: 1.00) and DMF (10 mL) and the mixture was cooled to 0° C. and a solution of NBS (82.1 mg, 461 μmol, Eq: 1.00) in 2 mL DMF was added dropwise over 5 min. and the mixture warmed to RT. After 10 h the mixture was diluted with sat. NH4Cl and extracted with EtOAc. The combined extracts were washed with H2O, concentrated and the residue was purified by preparative TLC to give tert-butyl (S)-1-((S)-8-bromo-4-oxo-2′,3′,4,5,5′,6′-hexahydro-3H-spiro[benzo[b][1,4]oxazepine-2,4′-pyran]-3-ylamino)-1-oxopropan-2-yl(methyl)carbamate (300 mg, 98%).

Provenance & Evidence