Dicyclohexylcarbodiimide → Tert-butyl 5-(3-(3-chloro-4-isopropoxyphenyl)-1,2,4-oxadiazol-5-yl)isoindoline-2-carboxylate

Participants

Reaction Steps

To a solution of 2-(tert-butoxycarbonyl)isoindoline-5-carboxylic acid (190 mg, 0.722 mmol) in acetonitrile (3 mL) in a 5 mL microwave vial was added HOBT (330 mg, 2.16 mmol), DCC (298 mg, 2.16 mmol), and DIEA (0.115 mL, 0.656 mmol). The mixture was stirred at room temperature for approximately 16 hours. Next, (Z)-3-chloro-N′-hydroxy-4-isopropoxybenzimidamide (150 mg, 0.656 mmol) (prepared by General procedure B) was added and the reaction was heated to 150° C. under microwave irradiation (max 300 W) for 20 minutes. After cooling, the reaction mixture was filtered, concentrated, and purified via Analogix system using RediSep 40 g column, with a gradient of 0-40% EtOAc/Heptane over 30 min. at a flow rate of 30 ml/min. Fractions containing product were combined, rotovapped, and dried in a vacuum oven to give tert-butyl 5-(3-(3-chloro-4-isopropoxyphenyl)-1,2,4-oxadiazol-5-yl)isoindoline-2-carboxylate (46.2 mg, 15.5%) LCMS (Table 1, Method c) Rt=3.40 min, m/z 456.22 (M+H)+; 1H NMR (400 MHz, DMSO) δ ppm 8.16 (d, 1H), 8.10 (s, 1H), 8.05 (d, 1H), 7.61 (m, 1H), 7.39 (d, 1H), 4.82 (sept, 1H), 4.70 (d, 4H), 1.48 (s, 9H), 1.35 (d, 6H).

Provenance & Evidence