(2R)-2-amino-3-methylbutanenitrile

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2-Hydroxy-2-(4-(5-(3-phenyl-4-(trifluoromethyl)isoxazol-5-yl)-1,2,4-oxadiazol-3-yl)phenyl)acetic acid (Int-Va, 40 mg, 0.093 mmol), (R)-2-amino-3-methylbutanenitrile (Int-VII, 9.10 mg, 0.093 mmol), HATU (45.8 mg, 0.121 mmol), and 4-methylmorpholine (37.5 mg, 0.371 mmol) were dissolved in DMF (1 mL). After stirring 1 h, the mixture was purified by prep HPLC (PHENOMENEX® Luna 5u 21.2×250 mm, gradient elution with Method 2—CH3CN/water containing 0.1% trifluoroacetic acid as defined above, 0% B to 100% B over 35 min, 20 mL/min, 220 nM, product retention=30.3 min) to provide single enantiomer N—((R)-1-cyano-2-methylpropyl)-2-hydroxy-2-(4-(5-(3-phenyl-4-(trifluoromethyl)isoxazol-5-yl)-1,2,4-oxadiazol-3-yl)phenyl)acetamide (20 mg, 0.037 mmol, 40.1% yield): LCMS=512.1 [M+H]+; 1H NMR (400 MHz, methanol-d4) δ ppm 8.90 (1 H, d, J=8.58 Hz), 8.13-8.26 (2 H, m), 7.50-7.81 (7 H, m), 5.21 (1 H, s), 4.54-4.69 (1 H, m), 2.05-2.25 (1 H, m), 1.09 (3 H, d, J=6.82 Hz), 0.98 (3 H, d, J=6.60 Hz); HPLC peak RT=10.5 min (Method A). the mixture was purified by prep HPLC (PHENOMENEX® Luna 5u 21.2×250 mm, gradient elution with Method 2—CH3CN/water containing 0.1% trifluoroacetic acid as defined above, 0% B to 100% B over 35 min, 20 mL/min, 220 nM, product retention=30.3 min)