The hydroxy amide cyclopentyl-(S)-1-((3S,5R)-3-((S)-1-(cyclopropylamino)-2-hydroxy-1-oxohexan-3-ylcarbamoyl)-8-oxo-7-phenyl-2,7-diazaspiro[4.4]nonan-2-yl)-3,3-dimethyl-1-oxobutan-2-ylcarbamate (J6a) (4.1 mg, 6.3 μmol) was dissolved in CH2Cl2 (1.0 ml) and treated with Dess-Martin periodinane (DMP, 8.0 mg, 18.9 μmol, 3 eq) for 3 hrs at room temp. The reaction was quenched with 1M sodium thiosulfate in water (32 μl, 5 eq). The reaction was loaded onto silica (eluted with ethyl acetate/hexane gradient) to give cyclopentyl-(S)-1-((3S,5R)-3-((S)-1-(cyclopropylamino)-1,2-dioxohexan-3-ylcarbamoyl)-8-oxo-7-phenyl-2,7-diazaspiro[4.4]nonan-2-yl)-3,3-dimethyl-1-oxobutan-2-ylcarbamate (compound no. 1) (3.1 mg, 4.8 μmol) as a white solid. NMR (CDCl3) δ5195m, 46H), 1.96 (m, 1H), 2.25 (m, 1H), 2.61 (m, 2H), 2.80 (s, 2H), 3.60 (dd, 2H), 4.00 (d, 1H), 4.22 (m, 2H), 4.70 (m, 1H), 4.90 (m, 1H), 5.20 (d, 1H), 5.35 (m, 1H), 6.90 (s, 1H), 7.19 (m, 1H), 7.38 (m, 2H), 7.65 (d, 1H). LCMS for C35H49N5O7 651.36 [M], found ES+ 652.5 [M+H]+ and ES− 650.6 [M−H]−, at 3.2 minutes retention time, using 10-90% acetonitrile/water (with 0.1% formic acid buffer) gradient over 5 minutes. The minor diastereomer cyclopentyl (S)-1-((3S,5S)-3-((S)-1-(cyclopropylamino)-1,2-dioxohexan-3-ylcarbamoyl)-8-oxo-7-phenyl-2,7-diazaspiro[4.4]nonan-2-yl)-3,3-dimethyl-1-oxobutan-2-ylcarbamate (compound no. 4) (1.4 mg, 2 pimp was obtained in similar fashion. 1H NMR (CDCl3) δ0.52 (m, 2H), 71m, 14H), 1.0-2.0 (m, 22H), 2.10 (m, 1H), 2.45-2.75 (m, 4H), 3.64 (t, 2H), 3.90 (d, 2H), 4.15 (d, 1H), 4.60 (m, 1H), 5.00 (m, 1H), 5.13 (d, 1H), 5.25 (m, 1H), 6.80 (m, 1H), 7.10 (m, 2H), 7.30 (m, 4H), 7.50 (m, 2H), 7.90 (m, 1H); LCMS for C35H49N5O7 651.36 [M], found ES+652.5 [M+H]+ and ES− 650.6 [M−H]−, at 3.2 minutes retention time, using 10-90% acetonitrile/water (with 0.1% formic acid buffer) gradient over 5 minutes.
