Hydrochloric Acid → Ethyl (2E)-3-{5-chloro-6-[(3R)-3-pyrrolidinylamino]-3-pyridyl}acrylate dihydrochloride

A mixture of tert-butyl (3R)-3-({3-chloro-5-[(1E)-3-ethoxy-3-oxo-1-propen-1-yl]-2-pyridinyl}amino)-1-pyrrolidinecarboxylate (0.98 g) and 4N hydrogen chloride in dioxane solution (5 ml) in EtOH (10 ml) was stirred at ambient temperature for 4 hours. The reaction mixture was evaporated in vacuo and the residue was triturated with hexane was collected by filtration to give ethyl (2E)-3-{5-chloro-6-[(3R)-3-pyrrolidinylamino]-3-pyridinyl}acrylate dihydrochloride (0.9 g).ethyl (2E)-3-{5-chloro-6-[(3R)-3-pyrrolidinylamino]-3-pyridinyl}acrylate dihydrochloride