Hydrochloric Acid → 2-Hydrazinyl-5-tosyl-5H-pyrrolo[2,3-b]pyrazine

Participants

Reaction Conditions

Reaction Steps

To a mixture of tert-butyl 2-(5-tosyl-5H-pyrrolo[2,3-b]pyrazin-2-yl)hydrazinecarboxylate and tert-butyl 1-(5-tosyl-5H-pyrrolo[2,3-b]pyrazin-2-yl)hydrazinecarboxylate (18.8 g, 46.6 mmol) in 1,4-dioxane (239 mL) was added HCl (4 M in 1,4-dioxane, 86 mL, 345 mmol). The reaction was heated at about 60° C. for about 1 h and then cooled to about 15-20° C. The solid was collected by vacuum filtration, washed with cold 1,4-dioxane (2×20 mL), and then stirred with a solution of saturated NaHCO3 and water (1:1, 150 mL). After about 1 h, the effervescence had subsided and the solid was collected by vacuum filtration, washed with ice cold water (3×20 mL), and dried in a vacuum oven to a constant weight to afford 2-hydrazinyl-5-tosyl-5H-pyrrolo[2,3-b]pyrazine as a light yellowish brown solid (8.01 g, 50%): LC/MS (Table 2, Method d) Rt=1.28 min; MS m/z: 304 (M+H)+.

Provenance & Evidence