反应详情

A mixture of 2-bromo-5-cyano-benzoic acid methyl ester (which may be prepared as described for Intermediate 2; 17.4 g, 72.6 mmol), 2-nitrophenylboronic acid (available from Aldrich Chemical Company, Inc.; 13.2 g, 79.9 mmol), Pd(dppf)Cl2 (available from Aldrich Chemical Company, Inc.; 7 g, 8.7 mmol) and K2CO3 (29.9 g, 218 mmol) in a mixture of water (26.5 mL) and dioxane (530 mL) was heated at reflux for 3.5 h. The reaction mixture was cooled and evaporated to dryness. The residue was co-evaporated with toluene, and then purified by silica gel chromatography, using 20-33% ethyl acetate/petroleum ether as eluent, to give 4-cyano-2′-nitro-biphenyl-2-carboxylic acid methyl ester (10.4 g, 51%). 1H NMR (300 MHz, CDCl3) δ 8.38 (d, J=1.7 Hz, 1H), 8.20 (d, J=8.0 Hz, 1H), 7.88-7.83 (m, 1H), 7.71-7.57 (m, 2H), 7.37 (d, J=7.9 Hz, 1H), 7.30-7.22 (m, 1H), 3.71 (s, 3H).

1. temperaturewas heated
2. temperatureat reflux for 3.5 h
3. temperatureThe reaction mixture was cooled
4. customevaporated to dryness
5. custompurified by silica gel chromatography