tert-butyl 1-[[(2S)-1-[(Z)-1-aminoethylideneamino]oxy-3,3-dimethyl-1-oxobutan-2-yl]carbamoyl]-3-phenyl-6,8-dihydro-5H-imidazo[1,5-a]pyrazine-7-carboxylate → (S)-tert-butyl 1-(2,2-dimethyl-1-(3-methyl-1,2,4-oxadiazol-5-yl)propylcarbamoyl)-3-phenyl-5,6-dihydroimidazo[1,5-a]pyrazine-7(8H)-carboxylate

Participants

Reaction Steps

Intermediate 22C (0.20 g, 0.39 mmol) was dissolved in a 1N solution of TBAF in THF (0.55 mL). The resulting mixture was stirred overnight, concentrated, diluted with EtOAc and washed successively with water and brine, dried over anhydrous Na2SO4, filtered and concentrated. The residue was purified by preparative flash chromatography on silica, eluting with a 20-70% ethyl acetate/hexanes gradient to provide Intermediate 22D (0.17 g, 88%). 1H-NMR (400 MHz, CDCl3-d) δ: 1.09 (s, 9H), 1.51 (s, 9H), 2.40 (s, 3H), 3.78 (m, 2H), 4.11 (m, 2H), 5.01 (m, 2H), 5.37 (d, 1H), 7.35 (m, 3H), 7.64 (m, 2H), 7.78 (d, 1H); LCMS (+ESI) m/z 495.1 [M+H]+.

Provenance & Evidence