2-Chloroethyl chlorosulfonylcarbamate → 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-oxooxazolidine-3-sulfonamide

To a mixture of 2-chloroethyl chlorosulfonylcarbamate (prepared as detailed in Bioorg. Med. Chem. Lett., 2006 16, 3367-3370; 0.052 g, 0.236 mmol) and (1S,3R,4S)-3-ethyl-4-(6-tosyl-6H-pyrrolo[2,3-e][1,2,4]triazolo[4,3-a]pyrazin-1-yl)cyclopentanamine (0.100 g, 0.236 mmol, Example #8 Step M) in DCM (2.4 mL) was added TEA (0.098 mL, 0.71 mmol) and the reaction mixture was stirred at ambient temperature for about 1 h. The reaction mixture was concd under reduced pressure to give 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-oxooxazolidine-3-sulfonamide (0.098 g, 65%) as a light brown solid: LC/MS (Table 1, Method a) Rt=2.18 min; MS m/z 574 (M+H)+.