Ammonium Chloride → 2-(1-Pyridin-2-yl-cyclopentyl)-acetamidine hydrochloride

To a stirred suspension of NH4Cl (1.05 g, 19.355 mmol) in dry toluene (15 mL) was added tri-methyl aluminum (2M) (5.2 mL, 10.323 mmol) at 5° C. The reaction mixture was warmed to room temperature and the reaction mixture was stirred for 2 h. A solution of (1-pyridin-2-yl-cyclopentyl)-acetonitrile (434) (1.2 g, 6.45 mmol) in toluene (5 mL) was added to above reaction mixture and the reaction mixture was stirred for 14 h at 100° C. After completion of the reaction, the reaction mixture was quenched with a suspension of silica gel (5 g) in chloroform (30 mL) and reaction mixture was stirred for half an hour at room temperature. It was filtered through a sintered funnel and the residue (silica gel) was washed with methanol (30 mL). The combined filtrate was concentrated and the resulting crude mass was stirred with 10% methanol in dichloromethane (100 mL). The thus generated suspension was filtered and the filtrate was concentrated under reduced pressure to get 2-(1-pyridin-2-yl-cyclopentyl)-acetamidine hydrochloride (435) (1.05 g, 80%) as a white solid.