[Synthesis]
The general procedure for the synthesis of 3-isothiocyanato-1,1'-biphenyl from 3-aminobiphenyl and N,N'-thiocarbonyldiimidazole was as follows: to a stirred solution of 3-aminobiphenyl (338 mg, 2 mmol) in dichloromethane (DCM, 5 mL) under nitrogen protection, N,N'-thiocarbonyldiimidazole (TCDI, 535 mg, 3 mmol) and 4 -dimethylaminopyridine (DMAP, 48.8 mg, 0.04 mmol). The reaction mixture was stirred continuously at room temperature for 1 h. The progress of the reaction was monitored by thin layer chromatography (TLC) until the starting materials were completely consumed. Upon completion of the reaction, the mixture was purified by passing through a silica gel column (with DCM as eluent). Subsequently, the solvent was removed under reduced pressure to afford the colorless oily product 3-isothiocyanato-1,1'-biphenyl (407 mg, 96% yield). The Rf value of the product was 0.86 (eluent ratio 1:1 DCM/hexane). Nuclear magnetic resonance hydrogen spectrum (1H NMR, CDCl3) showed: δ 7.16 (ddd, 1H, J=8.2, 2.1 Hz, H6'), 7.34-7.48 (m, 6H, H4', H5', H4'', H3', H5'', H2'), 7.52 (m, 2H, H2'', H6''). The nuclear magnetic resonance carbon spectrum (13C NMR, CDCl3) showed δ 124.4 (CH), 124.5 (CH), 126.2 (CH), 127.2 (CH), 128.2 (CH), 129.1 (CH), 130.0 (CH), 131.8 (C), 135.7 (NCS), 139.5 (C), 143.0 (C ). |