tert-Butyl ((2R,5R)-5-(2-fluoro-5-nitrophenyl)-2,5-dimethyl-2-(trifluoromethyl)-5,6-dihydro-2H-1,4-oxazin-3-yl)carbamate → [(2R,5R)-5-(5-Amino-2-fluoro-phenyl)-2,5-dimethyl-2-trifluoromethyl-5,6-dihydro-2H-[1,4]oxazin-3-yl]-carbamic acid tert-butyl ester

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Reaction Steps

A solution of [(2R,5R)-5-(2-fluoro-5-nitro-phenyl)-2,5-dimethyl-2-trifluoromethyl-5,6-dihydro-2H-[1,4]oxazin-3-yl]-carbamic acid tert-butyl ester (0.98 g, 2.25 mmol) in isopropanol-THF 2:1 (24 ml) was hydrogenated over 5% Pd—C for 4 h at 50° C. The catalyst was filtered off over Celite and the filtrate was concentrated to provide the title compound after crystallization from TBME-hexane as beige crystals: TLC (hexane-EtOAc 1:1): Rf=0.42; UPLC RtH5=0.955 min; ESIMS: 406 [(M+H)+]; 1H NMR (360 MHz, CDCl3): δ 6.82 (dd, 1H), 6.52 (m, 2H), 4.30 (dd, 1H), 3.97 (dd, 1H), 3.06 (br s, 2H), 1.58 (s, 3H), 1.48 (s, 3H), 1.46 (s, 9H).

Provenance & Evidence