Triethylamine → 3-(2-Pyridyl)-5-(3-cyano-5-nitrophenyl)-1,2,4-oxadiazole

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Using the general procedure for the preparation of acid chlorides, 3-cyano-5-nitrobenzoyl chloride was prepared from 3-cyano-5-nitrobenzoic acid (1.0 g, 5.1 mmol). A solution of the acid chloride in dichloromethane (5 mL) at 0° C. was treated with pyrid-2-ylamidoxime (700 mg, 5.1 mMol) and triethylamine (2.1 mL, 15.3 mmol) and then stirred at ambient temperature for 1 hour. The reaction mixture was washed with water and saturated brine, dried over anhydrous sodium sulfate, filtered, and concentrated. The residue was dissolved in N,N-dimethylformamide (5 mL) and heated at 110° C. for 4 hours. Standard work up and silica gel chromatography using hexanes:ethyl acetate:dichloromethane (3.5:0.5:4) afforded 149 mg (50%) of 3-(2-pyridyl)-5-(3-cyano-5-nitrophenyl)-1,2,4-oxadiazole: 1H NMR (CDCl3), 6 (ppm): 9.35 (d, 1H), 8.91 (s, 1H), 8.89 (d, 1H), 8.75 (s,1H), 8.26 (d, 1H), 7.94 (m, 1H), 7.53 (m, 1H).

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