8-(4-Fluorobenzylidene)-4-(4-fluorophenyl)-7,8-dihydro-5H-pyrano[4,3-d]pyrimidin-2-amine 8-(4-Fluorobenzylidene)-4-(4-fluorophenyl)-7,8-dihydro-5H-pyrano[4,3-d]pyrimidin-2-ylamine AIDS-150904 AIDS150904 NSC689281