反应详情

To a mixture of 5-phenyl-4-(trifluoromethyl)isoxazole-3-carbonyl fluoride (100 mg, 0.386 mmol) and (Z)-tert-butyl 1-(4-(N′-hydroxycarbamimidoyl)benzyl)azetidine-3-carboxylate (Int.1, 118 mg, 0.386 mmol) in acetonitrile (2 mL) at room temperature was added Hunig's Base (0.081 mL, 0.463 mmol). The reaction mixture was stirred at room temperature for 3 days. The volatiles were removed under reduced pressure, and the residue was partitioned between dichloromethane (30 mL) and a saturated aqueous solution of sodium bicarbonate (30 mL). The aqueous layer was extracted with dichloromethane (2×20 mL), and the combined organic layers were dried over anhydrous magnesium sulfate and concentrated to afford a light yellow oil. The compound was purified by flash silica gel chromatography using a mixture of ethyl acetate/hexane (0-70%) to give tert-butyl 1-(4-(5-(5-phenyl-4-(trifluoromethyl)isoxazol-3-yl)-1,2,4-oxadiazol-3-yl)benzyl)azetidine-3-carboxylate (175 mg, 0.332 mmol, 86% yield) as a white, crystalline solid. The compound had an HPLC retention time=3.34 minutes (YMC-Combi 4.6×50 mm S-5 ODS column) eluting with 10-90% aqueous methanol+0.2% phosphoric acid over a 4 minute gradient. MS: (M+H)=527.13. 1H NMR (400 MHz, CDCl3) δ ppm 1.47 (s, 9H), 3.26-3.33 (m, 3H), 3.54-3.59 (m, 2H), 3.70 (s, 2H), 7.46 (d, J=8.28 Hz, 2H), 7.56-7.62 (m, 2H), 7.63-7.68 (m, 1H), 7.78 (d, J=7.28 Hz, 2H), and 8.16 (d, 2H).

1. customThe volatiles were removed under reduced pressure
2. customthe residue was partitioned between dichloromethane (30 mL)
3. extractionThe aqueous layer was extracted with dichloromethane (2×20 mL)
4. dry with materialthe combined organic layers were dried over anhydrous magnesium sulfate
5. concentrationconcentrated
6. customto afford a light yellow oil
7. customThe compound was purified by flash silica gel chromatography
8. additiona mixture of ethyl acetate/hexane (0-70%)