Hydrochloric Acid → 3-Ethyl-4-(6-tosyl-6H-pyrrolo[2,3-e][1,2,4]triazolo[4,3-a]pyrazin-1-yl)cyclopentanamine

A round-bottomed flask was charged with tert-butyl-3-ethyl-4-(6-tosyl-6H-pyrrolo[2,3-e][1,2,4]triazolo[4,3-a]pyrazin-1-yl)cyclopentylcarbamate (1.7 g, 3.2 mmol) and 1,4-dioxane (20 mL) to give a brown solution. HCl (4 N in 1,4-dioxane, 4.05 mL, 16.2 mmol) was added and the mixture was stirred at about 40° C. for about 3 h. The solvent was removed under reduced pressure. EtOAc (50 mL) and saturated aqueous NaHCO3 (20 mL) were added. The resulting solid was collected by vacuum filtration and dried on the lyophilizer to give a grey solid (0.93 g). The layers of the filtrate were partitioned and the aqueous layer was extracted with EtOAc (3×40 mL). The organic layer was dried over anhydrous MgSO4, filtered, and the solvent was removed under reduced pressure to give a brown residue (0.52 g). The material obtained was combined to give 3-ethyl-4-(6-tosyl-6H-pyrrolo[2,3-e][1, 2, 4]triazolo[4,3-a]pyrazin-1-yl)cyclopenta amine (1.45 g, 80% UV purity, 84%): LC/MS (Table 2, Method a) Rt=1.76 min; MS m/z: 425 (M+H)+.