2-THIOPHENECARBOXIMIDIC ACID ETHYL ESTER → HCID 67070782, compound

Participants

Reaction Steps

3-[3-(3-chloro-phenyl)-[1,2,4]oxadiazol-5-yl]-propionic acid hydrazide (266.69 mg, 1 mmol) was mixed with thiophene-2-carboximidic acid ethyl ester (191.6 mg, 1 mmol) in ethanol (6 ml) and stirred at room temperature overnight. The reaction was quenched with water, extracted with ethyl acetate, dried and concentrated in vacuo. The crude product was triturated with hexane to yield 3-[3-(3-Chloro-phenyl)-[1,2,4]oxadiazol-5-yl]-propionic acid (ethoxy-thiophen-2-yl-methylene)-hydrazide as a white solid (305 mg, 75%). 1H-NMR(CDCl3) d(ppm): 8.99 (ws, 1H), 8.09 (s, 1H), 7.98 (d, 1H), 7.41(m, 4H), 7.08 (dd, 1H), 4.27 (q, 2H), 3.34 (m, 4H) and 1.41 (t, 3H). Step 2: 3-(3-Chloro-phenyl)-5-[2-(4-methyl-5-thiophen-2-yl-4H-[1,2,4]triazol-3-yl)-ethyl]-[1,2,4]oxadiazole: 3-[3-(3-chloro-phenyl)-[1,2,4]oxadiazol-5-yl]-propionic acid (ethoxy-thiophen-2-yl-methylene)-hydrazide (81 mg, 0.2 mmol) was mixed with 2M methylamine (0.3 ml in THF) in ethanol (2 ml) at 70˜80° C. overnight. The reaction mixture was concentrated with silica gel and purified by column chromatography with 0.5˜2.0% methanol in ethyl acetate to give 54 mg (72.5%) of 3-(3-chloro-phenyl)-5-[2-(4-methyl-5-thiophen-2-yl-4H-[1,2,4]triazol-3-yl)-ethyl]-[1,2,4]oxadiazole. 1H-NMR(CDCl3) d (ppm): 8.08 (s, 1H), 7.97 (d, 1H), 7.41 (m, 4H), 7.20 (dd, 1H), 3.80 (s, 3H), 3.68 (dd, 2H), 3.38 (dd, 2H).

Provenance & Evidence