Sodium Carbonate → 2-(9,9-dimethyl-9H-fluoren-2-yl)-1-methyl-4-(5-methylthiophen-2-yl)-1H-imidazole

Participants

Reaction Steps

A mixture of 2-iodo-1-methyl-4-(5-methylthiophen-2-yl)-1H-imidazole 6 (1.26 g, 4.16 mmol), (9,9-dimethyl-9H-fluoren-2-yl)boronic acid (1.19 g, 5.00 mmol), Na2CO3 (2.20 g, 20.8 mmol) in H2O (10 mL) and DMF (40 mL) was degassed (N2 bubbling). Pd(PPh3)4 (120 mg, 0.10 mmol) was added and the mixture was heated to reflux for 2 h. The mixture was allowed to cool to room temperature and concentrated. The mixture was filtered through Celite washing with CH2Cl2 and the combined filtrate and washings were concentrated. The residue was taken up in CH2Cl2 and H2O and the organic phase was separated. The aqueous phase was re-extracted (CH2Cl2) and the combined organics were washed (saturated aqueous NaCl), dried (MgSO4), filtered and concentrated to give a residue. The residue was purified by flash chromatography (EtOAc/hexanes 5:95 then 10:90 then 12:88) to give 2-(9,9-dimethyl-9H-fluoren-2-yl)-1-methyl-4-(5-methylthiophen-2-yl)-1H-imidazole 9 (1.19 g, 76%) as a colourless solid. A portion of this material was further purified by, firstly, recrystallisation (EtOAc/hexanes) and, secondly, by sublimation (180° C., 10−6 mBar): m.p. 188-191° C. (DSC)1H NMR (CDCl3, 400 MHz) δ1.53 (s, 6H), 2.50 (d, J=0.6 Hz, 3H), 3.76 (s, 3H), 6.68-6.71 (m, 1H), 7.11 (s, 1H), 7.13-7.19 (m, 1H), 7.32-7.40 (m, 2H), 7.43-7.49 (m, 1H), 7.58 (dd, J 1.4, 8.0 Hz, 1H), 7.73-7.81 (m, 3H); 13C NMR (CDCl3, 100 MHz) δ15.3, 27.1, 34.6, 47.0, 117.1, 119.8, 120.3, 122.1, 122.7, 123.6, 125.6, 127.0, 127.7, 137.8, 138.5, 139.9, 148.3, 153.9, 154.0; HRMS (EI) m/z 370.1490 C24H22N2S [M]+. requires 370.1498.

Provenance & Evidence