Diisopropylethylamine → {(S)-1-[1-(2-hydroxy-2-methyl-propyl)-1H-pyrazol-3-ylcarbamoyl]-3-methyl-butyl}-carbamic acid t-butyl ester

A solution of N-t-butoxycarbonyl-(L)-leucine mono-hydrate (2.81 g, 11.28 mmol) and 1-(3-amino-pyrazol-1-yl)-2-methyl-propan-2-ol (prepared in U.S. Pat. Appl. US2008021032 Example 80, 2.02 g, 13 mmol) in N,N-dimethylformamide (15 mL) was treated with N,N-diisopropylethylamine (3.5 mL, 20 mmol) and benzotriazol-1-yl-oxy-tris(dimethylamino)phosphonium hexafluorophosphate (8.84 g, 20 mmol) and stirred at room temperature for 12 h. At this time the mixture was concentrated in vacuo. The residue was partitioned between ethyl acetate and a concentrated ammonium chloride solution. The layers were separated and the organic layer was washed with water and brine, and dried over anhydrous sodium sulfate. The mixture was filtered and concentrated in vacuo and the residue purified by ISCO flash chromatography (RediSep silica 120 g, 20% to 80% ethyl acetate/hexanes) which afforded {(S)-1-[1-(2-hydroxy-2-methyl-propyl)-1H-pyrazol-3-ylcarbamoyl]-3-methyl-butyl}-carbamic acid t-butyl ester (4.15 g, 100%) as a white solid.

1. concentrationAt this time the mixture was concentrated in vacuo
2. customThe residue was partitioned between ethyl acetate
3. customThe layers were separated
4. washthe organic layer was washed with water and brine
5. dry with materialdried over anhydrous sodium sulfate
6. filtrationThe mixture was filtered
7. concentrationconcentrated in vacuo
8. customthe residue purified by ISCO flash chromatography (RediSep silica 120 g, 20% to 80% ethyl acetate/hexanes) which

ORD record

ord-4827150e902b432aabb31ece66583d4f

Source dataset

uspto-grants-2010_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07741327B2