Benzene → 5,7-Diphenylquinolin-8-ol

Participants

Reaction Steps

Reaction of 5,7-diiodo-quinolin-8-ol with 2-bromopropane following the method described in Example 8 gave 5,7-dibromo-8-isopropoxy-quinoline 7 (93%): 1H NMR (CDCl3): δ 8.86 (dd, J=1.5 and 4.4, 1 H), 8.46 (s, 1 H), 8.33 (dd, J=1.5 and 8.5, 1 H), 7.49 (dd, J=4.4 and 8.5, 1 H), 5.40 (m, 1 H), 1.43 (d, J=6.1, 6 H). To a stirred mixture of 7 (200 mg, 0.51 mmol), phenylboronic acid (143 mg, 1.17 mmol), 2 N Na2CO3 (7.2 mL), EtOH (1.2 mL) and benzene (6 mL) was added, under a blanket of argon, Pd(PPh3)4 (21 mg). The mixture was stirred under reflux for 16 h, cooled and concentrated. This provided, after column chromatography on silica (ethyl acetate/hexane, 1:9), 5,7-diphenyl-8-isopropoxy-quinoline as a yellow solid (157 mg, 91%). Cleavage of the isopropoxy group following the method outlined in Example 8 gave 5,7-diphenyl-8-hydroxy-quinoline M1 in 91% yield. (See table 4 for data).

Provenance & Evidence