Hydrochloric Acid → 5-(4-tert-butylphenylsulfonyl)-2-hydrazinyl-5H-pyrrolo[2,3-b]pyrazine

Participants

Reaction Conditions

Reaction Steps

To a mixture of tert-butyl 2-(5-(4-tert-butylphenylsulfonyl)-5H-pyrrolo[2,3-b]pyrazin-2-yl)hydrazinecarboxylate and tert-butyl 1-(5-(4-tert-butylphenylsulfonyl)-5H-pyrrolo[2,3-b]pyrazin-2-yl)hydrazinecarboxylate (11.24 g, 25.2 mmol, Preparation #2) in 1,4-dioxane (125 mL) was added HCl (4 M in 1,4-dioxane, 125 mL, 500 mmol). The reaction mixture was heated at about 60° C. for about 1 h and then the reaction mixture was cooled to ambient temperature. The mixture was filtered, while washing with Et2O (150 mL), and the solid was partitioned between EtOAc (500 mL) and saturated aqueous NaHCO3 (500 mL). The layers were separated and the organic layer was washed with saturated aqueous NaHCO3 and brine (200 mL each), dried over anhydrous Na2SO4, filtered, concentrated under reduced pressure, and dried in a vacuum oven at about 70° C. to give 5-(4-tert-butylphenylsulfonyl)-2-hydrazinyl-5H-pyrrolo[2,3-b]pyrazine as a tan solid (7.54 g, 87%): LC/MS (Table 2, Method a) Rt=2.20 min; MS m/z: 346 (M+H)+.

Provenance & Evidence