4?,7-Dimethoxy-N-methylisoflavone-3?-sulfonamide(3) was synthesized by a two step synthesis method and characterized via IR and 1H NMR. Its chemical structure was determined by X-ray single-crystal diffraction. It crystallizes in monoclinic, space group C2/c with a = 27.677(13), b = 10.490(5), c = 13.982(7) ?, β = 118.781(9)o, V = 3558(3) ?3, Z = 8, F(000) = 1568, Dc = 1.401 Mg/m3, Mr = 375.39, μ = 0.217 mm–1, λ = 0.71073 ?, the final R = 0.0436 and w R = 0.0910 for 3168 observed reflections with I > 2σ(I). The compound was studied subsequently for the potent neuroprotective activity, and showed effects against oxygen-glucose deprivation injury in PC12 cells in a dose-dependent manner(protection: 42.5% at 100 μg·m L-1, 35.1% at 10 μg·m L-1 and 22.5% at 1 μg·m L-1).