Cesium carbonate → ethyl 4-[5-(5-{3-cyano-4-[(1-methylethyl)oxy]phenyl}-1,2,4-oxadiazol-3-yl)-3,4-dihydro-2(1H)-isoquinolinyl]butanoate formic acid salt

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Reaction Steps

A suspension of 2-[(1-methylethyl)oxy]-5-[3-(1,2,3,4-tetrahydro-5-isoquinolinyl)-1,2,4-oxadiazol-5-yl]benzonitrile (Example 3, 28.8 mg, 0.080 mmol), ethyl 4-bromobutyrate (45.8 μl, 0.32 mmol) and Cs2CO3 (130 mg, 0.40 mmol) in DMF (2 mL) was stirred at room temperature for 1 h, and then irradiated to 60° C. for 5 min in the microwave. More ethyl 4-bromobutyrate (45.8 μl, 0.32 mmol) was added and the suspension was stirred at room temperature for 3.5 h. It was then filtered, concentrated in vacuo and purified by MDAP to give the title compound as a yellow film (8.0 mg, 21%). 1H NMR (400 MHz, CDCl3) δ 8.42 (1H, d), 8.34 (1H, dd), 8.27 (br. s), 8.09 (1H, d), 7.39 (1H, t), 7.27 (1H, d), 7.13 (1H, d), 4.80 (1H, sept), 4.19 (2H, s), 4.13 (2H, q), 3.47 (2H, t), 3.28 (2H, t), 2.99 (2H, t), 2.44 (2H, t), 2.10 (2H, quin), 1.48 (6H, d), 1.25 (3H, t); m/z (ES) 475 [M+H]+.

Provenance & Evidence