2-(1H-Pyrazol-5-yl)aniline

Typical Procedure:
A mixture of phenylboronic acid (1) (0.25 mmol) and 2-(1H-pyrazol-5-yl)aniline (0.25 mmol) in toluene (1 mL) is heated under reflux with a Dean-Stark condenser for 1 h. After being cooled to room temperature, the solvent is evaporated in vacuo. To the residue, RuH₂(CO)(PPh₃)₃ (0.0075 mmol) is added. After filling dry nitrogen in the glass tube, norbornene (1.25 mmol), triethylsilane (1.25 mmol) and toluene (0.13 mL) are added under a nitrogen atmosphere. The mixture is heated at 135 °C for 12 h. 2 is isolated by bulb-to-bulb distillation (280-290 °C / 4.7 mmHg, mp 138 °C, Y. 89%) as a white solid.