6-hydroxyquinoline-3-carboxylic acid

71082-47-8

1137826-05-1

Example 11: Synthesis of N-hydroxy-6-phenoxyquinoline-3-carboxamide compounds 1-12 Step 1: Preparation of 6-hydroxyquinoline-3-carboxylic acid intermediate-15-methoxyquinoline-3-carboxylic acid (0.75 g, 3.69 mmol) 6-Methoxyquinoline-3-carboxylic acid (0.75 g, 3.69 mmol) was placed in a 20 mL microwave reaction flask equipped with a stirrer. The solid was suspended in acetic acid (7 mL) followed by the addition of hydrobromic acid (48% aqueous solution, 3.5 mL). The reaction vial was sealed and the suspension was cautiously heated under microwave radiation at 140°C for 1 hour. Upon completion of the reaction, the reaction vial was thoroughly cooled to room temperature and opened in a fume hood after careful venting with an 18 g needle. The solid product was collected by filtration and washed with ethyl acetate to give the title product as a solid (0.678 g, 91% yield). LC-MS (formic acid system) ES+ m/z: 190. 1H NMR (400 MHz, d6-DMSO) δ ppm: 10.68 (br s, 1H), 9.26 (d, J = 1.9Hz, 1H), 9.14 (d, J = 1.3Hz, 1H), 8.08 (d, J = 9.1Hz, 1H), 7.62 (dd, J = 9.1, 2.7Hz, 1H), 7.52 (d, J = 2.7Hz, 1H).