N,N'-Dimethylethylenediamine → tert-Butyl [(3R)-1-{4-[(Benzyloxy)methyl]-3-oxo-3,4-dihydro-2H-1,4-benzoxazin-6-yl}-5-oxopyrrolidin-3-yl]carbamate

Participants

Reaction Conditions

Reaction Steps

In a reaction vessel were weighed and charged 4-[(Benzyloxy)methyl]-6-bromo-2H-1,4-benzoxazin-3(4H)-one (366 mg, 1.05 mmol), tert-butyl [(3R)-5-oxopyrrolidin-3-yl]carbamate (200 mg, 1.00 mmol), cesium carbonate (652 mg, 2.00 mmol) and 1,4-dioxane (5 ml), which was purged with nitrogen gas, subsequently copper (I) iodide (190 mg, 1.00 mmol) and N,N′-dimethylethylenediamine (0.107 ml, 1.00 mmol) were added thereto, and the mixture was stirred with heating for 9 hours on an oil bath at 100° C. After lowering the temperature to room temperature, the reaction solution was diluted with a mixed solvent of chloroform-methanol (9:1) to remove insoluble material by filtration using celite. The filtrate was concentrated under reduced pressure. The residue was roughly purified by silica gel column chromatography (chloroform/methanol), subsequently crystallized in a mixed solvent of n-hexane-ethyl acetate (1:1) and collected by filtration to yield 373 mg (80%) of the title compound in the form of a white solid.

Provenance & Evidence