Potassium Carbonate → 2-(3,4-Dimethoxy-phenyl)-6-methyl-5-pyridin-3-yl-imidazo[2,1-b][1,3,4]thiadiazole

Participants

Reaction Steps

A mixture of 2-(3,4-dimethoxy-phenyl)-5-iodo-6-methyl-imidazo[2,1-b][1,3,4]thiadiazole (0.070 g, 0.174 mmol), pyridine-3-boronic acid (0.026 g, 0.209 mmol), Pd(dppf)Cl2.DCM (0.014 g. 0.017 mmol) and potassium carbonate (0.5 mL, sat. aq) in DME (1.7 mL) was heated in the microwave oven at 150° C. for 2 h. Since the conversion was incomplete, another 1.2 eq of pyridine-3-boronic acid and 0.1 eq of Pd(dppf)Cl2.DCM were added, and the mixture was subjected to another 7 hours of microwave irradiation at 150° C. The reaction mixture was cooled, diluted with DCM, washed with water, dried (Na2SO4) and concentrated. A yellow solid (0.055 g) was obtained that was purified by silica gel chromatography (cyclohexane/0-60% EtOAc) to give the desired product (white solid, 0.042 g, 39%). HPLC-MS: (5-100% B in 8 min, 0.8 mL/min, 50° C.): tR=4.09 min, [M+H]+ m/z 353.1. 1H NMR (300 MHz, CDCl3) δ/ppm 9.00 (d, J=2.2, 1H), 8.53 (dd, J=4.8, 1.6, 1H), 8.00 (dd, J=8.0, 1.8, 1H), 7.48-7.29 (m, 3H), 6.88 (d, J=9.0, 1H), 3.90 (d, J=5.0, 7H), 2.50 (s, 3H).

Provenance & Evidence