3-(2,2-Difluoro-1,3-benzodioxol-5-yl)-(2E)-propenoic Acid (CAS# 721-13-1) can be used to prepare pyrazolyl Ph urea derivatives as inhibitors of p38 kinase and/or tumor necrosis factor (TNF). It can also be used as an anti-cancer agent and for hepatitis C virus inhibitors.