Acetic Acid → tert-butyl-4-((5-tosyl-5H-pyrrolo[2,3-b]pyrazin-2-yl)methylcarbamoyl)bicyclo[2.2.2]octan-1-ylcarbamate

Participants

Reaction Conditions

Reaction Steps

To a solution of 5-tosyl-5H-pyrrolo[2,3-b]pyrazine-2-carbaldehyde (0.49 g, 1.6 mmol, Example #10, Step B) in MeOH (10 mL) was added hydroxylamine (50% in water, 0.199 mL, 3.25 mmol). The reaction mixture was heated to about 40° C. After about 2 h, the reaction mixture was cooled to ambient temperature and concentrated under reduced pressure. To a solution of the crude oxime in THF (10 mL) and AcOH (0.93 mL, 16 mmol) was added zinc dust (<10 micron, 0.425 g, 6.50 mmol). After about 4 h at ambient temperature, the reaction mixture was diluted with DCM and saturated aqueous NaHCO3 and filtered through Celite®. The layers were separated and the organic layer was dried over anhydrous Na2SO4, filtered, treated with HCl (4 N in 1,4-dioxane, 1 mL) and concentrated under reduced pressure. To a solution of the crude amine in DCM (10 mL) was added 4-(tert-butoxycarbonylamino)bicyclo[2.2.2]octane-1-carboxylic acid (0.48 g, 1.8 mmol, Prime Organics), TEA (0.23 mL, 1.6 mmol) and HATU (0.618 g, 1.63 mmol). After about 4 h at ambient temperature, the reaction mixture was diluted with DCM and saturated aqueous NaHCO3 and filtered through Celite®. The layers were separated and the organic layer was dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The crude amide was purified by chromatography on silica gel eluting with a gradient of 20-80% EtOAc in DCM to provide tert-butyl-4-((5-tosyl-5H-pyrrolo[2,3-b]pyrazin-2-yl)methylcarbamoyl)bicyclo[2.2.2]octan-1-ylcarbamate as a tan solid (0.205 g, 23%). LC/MS (Table 2, Method a) Rt=2.52 min; MS m/z: 554 (M+H)+.

Provenance & Evidence