Procedure

A mixture of 2-bromobenzoic acid (10.63 g, 52.9 mmol), 4-methoxythiophenol (6.57 g, 52.9 mmol), K,CO, (14.60 g, 105.8 mmol and powdered Cu bronze (1.71 g, 26.44 mmol) in DMF (100 mL) was stirred at reflux for 6 hours. Upon cooling, the reaction mixture was poured into ice (500 g) and acidified with concentrated HCl to pH=4 giving a white solid. The solid was isolated and dried at the vacuum pump*" to yield 2-(4-methoxyphenyl)thio)benzoic acid (6.10 g, 44%) as a white solid. 1H NMR (400 MHZ,DMS0-d6) 6 13.27 (s, 1H), 7.93 (dd, J= 7.7, 1.5 Hz, 1H), 7.7 (d, J= 8.5 Hz, 2H), 7.36 - 7.29 (m, 1H), 7.15 (td, J= 7.5, 1.2 Hz, 1H), 7.06 (d, J= 8.6 HZ, 2H), 6.65 (dd, J= 8.3, 1.2 Hz, 1H), 3.81 (s, 3H). 13C NMR (101 MHZ, DMSO) 167.80,160.80, 143.95,137.89, 132.81, 131.42, 127.13,126.37, 124.57, 122.41, 116.15, 55.77. MS m/z: 261.02 (M+).

References:

[1] ROBERT B. SMITH. Coupling of 2-bromobenzoic acid with 4-methoxyphenol under Ullmann conditions[J]. ChemSpider Synthetic Pages, 2018. DOI:10.1039/SP846.