[S:1]([N:11]1[C:15]2=[N:16][CH:17]=[C:18]([CH:20](O)[CH3:21])[N:19]=[C:14]2[CH:13]=[CH:12]1)([C:4]1[CH:10]=[CH:9][C:7]([CH3:8])=[CH:6][CH:5]=1)(=[O:3])=[O:2].O=S(Cl)Cl.[N-:27]=[N+:28]=[N-:29].[Na+].O>C(Cl)Cl.CCOC(C)=O.C([O-])(O)=O.[Na+]>[N:27]([CH:20]([C:18]1[N:19]=[C:14]2[CH:13]=[CH:12][N:11]([S:1]([C:4]3[CH:10]=[CH:9][C:7]([CH3:8])=[CH:6][CH:5]=3)(=[O:3])=[O:2])[C:15]2=[N:16][CH:17]=1)[CH3:21])=[N+:28]=[N-:29]To a solution of 1-(5-tosyl-5H-pyrrolo[2,3-b]pyrazin-2-yl)ethanol (0.600 g, 1.89 mmol) in DCM (10 mL) was added SOCl2 (0.690 mL, 9.45 mmol) at ambient temperature. After about 4 h the reaction mixture was diluted with EtOAc (50 mL) and saturated aqueous NaHCO3 (50 mL) was added to the reaction mixture. After gas evolution ceased, the organic layer was separated, dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The residue was dissolved in DMF (10 mL) and sodium azide (0.615 g, 9.45 mmol) was added to the reaction mixture. After about 15 h, EtOAc (50 mL) and water (50 mL) were added to the reaction mixture. The organic layer was separated, concentrated under reduced pressure, and purified by silica gel chromatography eluting with 20-80% EtOAc/heptane to provide 2-(1-azidoethyl)-5-tosyl-5H-pyrrolo[2,3-b]pyrazine (0.65 g, 100%) as a colorless solid: LC/MS (Table 2, Method a) Rt=2.67 min; MS m/z: 343 (M+H)+.
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