[Br:1][C:2]1[N:3]=[CH:4][C:5](=[N:15]S(C2C=CC(C)=CC=2)(=O)=O)[N:6]([CH:8]([CH3:14])[C:9]([CH:11]2[CH2:13][CH2:12]2)=O)[CH:7]=1.FC(F)(F)C(OC(=O)C(F)(F)F)=O>C1COCC1>[Br:1][C:2]1[N:3]=[CH:4][C:5]2[N:6]([C:8]([CH3:14])=[C:9]([CH:11]3[CH2:13][CH2:12]3)[N:15]=2)[CH:7]=1To a solution of N-(5-bromo-1-(1-cyclopropyl-1-oxopropan-2-yl)pyrazin-2(1H)-ylidene)-4-methylbenzenesulfonamide (1.24 g) in THF (10 ml) was added trifluoroacetic anhydride (1.23 g) at 0° C., and the mixture was heated at 60° C. for 3 h. The mixture was partitioned between EtOAc and saturated NaHCO3 solution, and the organic layer was washed with 1 M NaOH and brine successively, dried over MgSO4, concentrated in vacuo, and purified by silica gel column chromatography (hexane/EtOAc) to give the title compound (593 mg) as pale yellow crystals.
Wird geladen…