The present invention relates to the alkylidene phosphonate esters of formula I wherein, R1 is selected from a group consisting of hydrogen or alkyl group R2 is selected from a group consisting of hydrogen, hydroxy, alkyl, alkoxy, nitro, halogen, amino, N- substituted alkylamino alkyl group is selected from a group consisting of methyl, ethyl and isopropyl Ar is selected from a group consisting of aryl, substituted aryl, fused aryl, heteroaryl, and substituted heteroaryl. The present invention particularly relates to synthesis and p-glycoprotein induction activity of the alkylidene phosphonate esters. In addition, the invention relates to methods of using compounds for treating or preventing Alzheimers disease.
