Ethyl Acetate → 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)acetamide

Participants

Reaction Conditions

Reaction Steps

To a mixture of (1S,2R,4S)-4-acetamido-2-ethylcyclopentanecarboxylic acid (3.03 g, 15.2 mmol) in DCM (90 mL) was added 2-hydrazinyl-5-tosyl-5H-pyrrolo[2,3-b]pyrazine (4.20 g, 13.8 mmol, Example #4, Step D), HATU (5.53 g, 14.5 mmol) and TEA (7.72 mL, 55.4 mmol). After stirring at ambient temperature for about 2 h, the reaction was diluted with water (60 mL). The layers were separated and the aqueous layer was extracted with DCM (3×50 mL). The combined organic layers were washed with brine (50 mL), dried over anhydrous MgSO4, filtered, and concd under reduced pressure. The crude material was purified by silica gel chromatography eluting with a gradient of 0-5% MeOH in DCM to give N-((1S,3R,4S)-3-ethyl-4-(2-(5-tosyl-5H-pyrrolo[2,3-b]pyrazin-2-yl)hydrazinecarbonyl)cyclopentyl)acetamide (7.0 g, 90%, 87% purity) as a tan foam: LC/MS (Table 1, Method a) Rt=1.96 min; MS m/z: 485 (M+H)+. To a solution of impure N-((1S,3R,4S)-3-ethyl-4-(2-(5-tosyl-5H-pyrrolo[2,3-b]pyrazin-2-yl)hydrazinecarbonyl)-cyclo-pentyl)acetamide (9.40 g, 19.4 mmol) in 1,4-dioxane (100 mL) was added TEA (8 mL, 58 mmol) and thionyl chloride (1.9 mL, 27.1 mmol). The reaction mixture was heated at about 80° C. for about 2 h, and then cooled to about 0° C. and saturated aqueous NaHCO3 and EtOAc (100 mL each) were added. The layers were separated and the aqueous layer was extracted with additional EtOAc (2×100 mL). The combined organic layers were washed with brine (100 mL), dried over anhydrous MgSO4, filtered, and concd under reduced pressure. The crude material was purified by silica gel chromatography eluting with a gradient of 50-100% EtOAc/MeOH/Et2NH (90:9:1) in EtOAc 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)acetamide (6.00 g, 66%): LC/MS (Table 1, Method a) Rt=2.03 min; MS m/z: 467 (M+H)+.

Provenance & Evidence