Diisopropylethylamine → methyl (1S)-1-({[(1S,3S,4S)-3-hydroxy-4-{[(2S)-2-hydroxy-3,3-dimethylbutanoyl]amino}-5-phenyl-1-(4-pyridin-2-ylbenzyl)pentyl]amino}carbonyl)-2,2-dimethylpropylcarbamate

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Reaction Conditions

Reaction Steps

A solution of the product of Example 2C (0.020 g, 0.038 mmol) in tetrahydrofuran (0.40 mL) was treated with (s)-(−)-2-hydroxy-3,3-dimethylbutyric acid (0.006 g, 0.045 mmol), DEPBT (0.017 g, 0.057 mmol), and N,N-diisopropylethylamine (0.035 mL, 0.201 mmol), stirred at 25° C. for 2 hours and partitioned between ethyl acetate and 10% Na2CO3 solution. The organic layer was washed with additional 10% Na2CO3 solution and brine, dried over MgSO4, filtered and concentrated. The residue was chromatographed on silica gel eluting with a gradient starting with dichloromethane and ending with ethyl acetate to give the title compound (0.005 g, 21% yield). 1H NMR (300 MHz, DMSO-d6), δ ppm 0.70 (s, 9 H), 0.79 (s, 9 H), 1.42-1.54 (m, 2 H), 2.71-2.76 (m, 3 H), 3.42 (d, J=5.9 Hz, 1 H), 3.48 (s, 3 H), 3.61-3.67 (m, 1 H), 3.82 (d, J=9.9 Hz, 1 H), 4.10-4.21 (m, 2 H), 4.98 (d, J=5.5 Hz, 1 H), 5.33 (d, J=5.8 Hz, 1 H), 6.65 (d, J=9.6 Hz, 1 H), 7.09-7.24 (m, 9 H), 7.28-7.32 (m, 1 H), 7.80 (d, J=8.5 Hz, 1 H), 7.84-7.89 (m, 4 H), 8.62 (m, 1 H).

Provenance & Evidence