Potassium Carbonate → (4R,5S)-ethyl 4-((tert-butoxycarbonyl)amino)-5-((tert-butyldimethylsilyl)oxy)-2-(2-(3-(cyclopropylamino)-6-fluoro-2-methylquinoxalin-5-yl)-2-oxoethyl)-3-oxohexanoate

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Reaction Steps

This compound (2.43 g, 73% yield) as a bright yellow crystalline solid was prepared according to the procedures described for Intermediate 352b, using 2-bromo-1-(3-(cyclopropylamino)-6-fluoro-2-methylquinoxalin-5-yl)ethanone (613) (1.82 g, 5.39 mmol) and (4R,5S)-ethyl 4-((tert-butoxycarbonyl)amino)-5-((tert-butyldimethylsilyl)oxy)-3-oxohexanoate (615) (2.61 g, 6.47 mmol) and K2CO3 (0.931 g, 6.73 mmol) in DMF (10 mL) as the strafing materials, followed by subsequent treatment of the resulting (4R,5S)-ethyl 4-((tert-butoxycarbonyl)amino)-5-((tert-butyldimethylsilyl)oxy)-2-(2-(3-(cyclopropylamino)-6-fluoro-2-methylquinoxalin-5-yl)-2-oxoethyl)-3-oxohexanoate (353a) (3.42 g, 96% yield, LC-MS m/z 661.1, [M+H]+) with NH4OAc (5.98 g, 78 mmol) in 10 mL of EtOH and 5 mL of AcOH. 19F NMR (DMSO-d6; 376 MHz): δ −110.91 (s, 1F). LC-MS m/z 642.2, [M+H]+.

Provenance & Evidence