Phosphoric Acid → 5-tosyl-5H-pyrrolo[2,3-b]pyrazin-2-amine

Participants

Reaction Conditions

Reaction Steps

To a solution of tert-butyl 5-tosyl-5H-pyrrolo[2,3-b]pyrazin-2-ylcarbamate (12.35 g, 31.8 mmol, Example #3 Step E) in THF (35 mL) was added H3PO4 (20.16 mL, 350 mmol). The reaction mixture was heated to about 65° C. After about 90 min, the reaction mixture was cooled to about 0° C. and a solution of K3PO4 (29.0 mL, 350 mmol) in water (100 mL) was added. A white precipitate was removed by filtration. The organic layer was separated, dried over anhydrous MgSO4, and concd in vacuo to provide crude 5-tosyl-5H-pyrrolo[2,3-b]pyrazin-2-amine (8.58 g, 94%) as a tan solid: LC/MS (Table 1, Method a) Rt=1.85 min; MS m/z: 289 (M+H)+.

Provenance & Evidence