Diisopropylethylamine → 2-((3-(5-Phenyl-4-(trifluoromethyl)isoxazol-3-yl)-4,5-dihydronaphtho[1,2-c]isoxazol-7-yl)methyl)-2,5,7-triazaspiro[3.4]octane-6,8-dione

Participants

Reaction Conditions

Reaction Steps

To a stirred mixture of 7-(bromomethyl)-3-(5-phenyl-4-(trifluoromethyl)isoxazol-3-yl)-4,5-dihydronaphtho[1,2-c]isoxazole (Preparation 6C, 25 mg, 0.053 mmol), 2,5,7-triazaspiro[3.4]octane-6,8-dione, hydrochloric acid (Preparation 17B, 11 mg, 0.079 mmol), and anhydrous dimethylformamide (0.5 mL) was added N,N-diisopropylethylamine (0.046 mL, 0.263 mmol) dropwise at 0° C. The mixture was stirred at 0° C. for 30 min and at room temperature for 80 min. The reaction mixture was concentrated and subjected to prep HPLC conditions (PHENOMENEX® Luna Axia 30×100 mm; 10 min. gradient; solvent A=10% MeOH, 90% H2O, 0.1% TFA, solvent B=90% MeOH, 10% H2O, 0.1% TFA). The desired fractions were concentrated to yield an aqueous suspension of the product, to which saturated aqueous sodium bicarbonate solution (1 mL) was added to make the mixture basic. The solid was filtered and washed with water (3×1 mL) and then lyophilized to give 2-((3-(5-phenyl-4-(trifluoromethyl)isoxazol-3-yl)-4,5-dihydronaphtho[1,2-c]isoxazol-7-yl)methyl)-2,5,7-triazaspiro[3.4]octane-6,8-dione (19 mg, 0.034 mmol, 65.4% yield) as a white solid. The compound had an HPLC retention time=3.19 min (condition C); LC/MS M+1=536.3; 1H NMR (400 MHz, MeOD) δ ppm 7.92 (1H, d, J=7.9 Hz), 7.77 (2H, d, J=7.3 Hz), 7.58-7.71 (3H, m), 7.40 (1H, s), 7.37 (1H, d, J=7.7 Hz), 3.78 (2H, s), 3.75 (2H, d, J=8.6 Hz), 3.48 (2H, d, J=8.8 Hz), 3.08 (4H, s).

Provenance & Evidence