tert-Butyl carbamate → 1,1-Dimethylethyl N-(5-((4-methylphenyl)sulfonyl)-5H-pyrrolo(2,3-b)pyrazin-2-yl)carbamate

Participants

Reaction Conditions

Reaction Steps

To a flask was added Pd2(dba)3 (1.3 g, 1.42 mmol), di-tert-butyl-(2′,4′,6′-triisopropyl-biphenyl-2-yl)-phosphane (1.21 g, 2.84 mmol), and 1,4-dioxane (75 mL). The catalyst-ligand mixture was degassed via vacuum/nitrogen purge (3 times) and heated at about 80° C. for about 10 min. Then 2-bromo-5-tosyl-5H-pyrrolo[2,3-b]pyrazine (5.0 g, 14.2 mmol, Preparation #7), tert-butyl carbamate (2.5 g, 21.29 mmol), and NaOt-Bu (2.05 g, 21.29 mmol) were added. After an additional vacuum/nitrogen purge, the reaction was heated at about 80° C. for about 16 h. The reaction was cooled to ambient temperature and diluted with EtOAc (70 mL). The reaction mixture was filtered and the filtrate was washed with water (3×20 mL). The organic layer was dried over anhydrous MgSO4, filtered, and solvent removed under reduced pressure to give a reddish-brown solid. The crude material was purified via silica gel chromatography eluting with a gradient of 10-50% EtOAc in heptane to yield tert-butyl 5-tosyl-5H-pyrrolo[2,3-b]pyrazin-2-ylcarbamate as a yellow amorphous solid (1.0 g, 18%): LC/MS (Table 2, Method a) Rt=2.63 min; MS m/z: 389 (M+H)+.

Provenance & Evidence