To a solution of (1S,3R,4S)-3-ethyl-4-(6-tosyl-6H-pyrrolo[2,3-e][1,2,4]triazolo[4,3-a]pyrazin-1-yl)cyclopentanamine (115 mg, 0.271 mmol, Preparation #BB.1*) in DCM (1.5 mL) was added DIEA (0.071 mL, 0.406 mmol) followed by 2-methylpropane-2-sulfinic chloride (0.037 mL, 0.298 mmol). After about 4 h the reaction mixture was diluted with EtOAc (10 mL) and aqueous saturated NaHCO3 (10 mL). The organic layer was separated, dried over anhydrous Na2SO4, filtered and concd in vacuo. The crude residue was dissolved in DCM (1.5 mL) and a freshly prepared solution of m-chloroperbenzoic acid (0.271 mL, 0.271 mmol, 1M in DCM) was added. After about 2 h the reaction mixture was diluted with EtOAc (10 mL) and saturated aqueous NaHCO3 (10 mL). The organic layer was separated, dried over anhydrous Na2SO4, filtered and concd in vacuo. The crude residue was purified by chromatography on silica gel eluting with EtOAc to provide N-((1S,3R,4S)-3-ethyl-4-(6-tosyl-6H-pyrrolo[2,3-e][1,2,4]triazolo[4,3-a]pyrazin-1-yl)cyclopentyl)-2-methylpropane-2-sulfonamide (95 mg, 64% yield) as an oil. LC/MS (Table 1, Method a) Rt=2.40 min; MS m/z: 545 (M+H)+.
