1-(8-ethyl-1,4-dioxaspiro[4.4]nonan-7-yl)-6-tosyl-6H-pyrrolo[2,3-e][1,2,4]triazolo[4,3-a]pyrazine → 1-(8-ethyl-1,4-dioxaspiro[4.4]nonan-7-yl)-6H-pyrrolo[2,3-e][1,2,4]triazolo[4,3-a]pyrazine

To the solution of 1-(8-ethyl-1,4-dioxaspiro[4.4]nonan-7-yl)-6-tosyl-6H-pyrrolo[2,3-e][1,2,4]triazolo[4,3-a]pyrazine (3.76 g, 8.04 mmol) in 1,4-dioxane (55 mL), aqueous sodium hydroxide solution (2N, 12 mL) was added and the reaction mixture was heated at about 60° C. for about 90 min. The solvent was removed and the residue partitioned between saturated solution of ammonium chloride in water and EtOAc (75 mL each). The aqueous phase was further washed with EtOAc (60 mL); the combined organic extracts were washed with brine (65 mL), dried over anhydrous magnesium sulfate, filtered, and concentrated to yield a brown solid. The solid was triturated in ether (20 mL) and the precipitate was collected by filtration and dried to yield 1-(8-ethyl-1,4-dioxaspiro[4.4]nonan-7-yl)-6H-pyrrolo[2,3-e][1,2,4]triazolo[4,3-a]pyrazine (2.22 g, 88%) as a beige solid. LC/MS (Table 1, Method a) Rt=1.71 min; MS m/z: 314 (M+H)+.