Diisopropylethylamine → 4-(4-cyclopropylethynyl-2-oxo-4-trifluoromethyl-1,4-dihydro-2H-benzo[d][1,3]oxazin-6-yloxy)-butyric Acid 2,5-dioxo-pyrrolidin-1-yl Ester

Participants

Reaction Steps

A solution of 35 mg (0.091 mmol) of the acid 11 in 2 mL of anhydrous THF was cooled to 0° C., and 30 μL (0.15 mmol) of N,N-diisopropylethylamine was added followed by 40 mg (1.28 mmol) of O-(N-succinimidyl)-N,N,N′,N′-tetramethyluronium tetrafluoroborate. The reaction mixture was allowed to warm up to room temperature. The reaction mixture was concentrated under reduced pressure, and the residue was purified by RP preparative HPLC using acetonitrile and water as a mobile phase containing 0.1% of trifluoroacetic acid to give 30 mg (00.62 mmol, 68%) of 12 as a white powder [LC-MS; M+H 481.0].

Provenance & Evidence