The present invention relates to the alkylidene phosphonate esters of formula I wherein, R.sub.1 is selected from a group consisting of hydrogen or alkyl group; R.sub.2 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 Alzheimer's disease.

##STR00001##

Disclosed is a phosphorus-containing compound capable of serving as a flame retardant to be used in conjunction with other ingredients to make resin compositions, useful for fabricating such as a prepreg, a resin film, a resin film with copper foil, a laminate or a printed circuit board, having improved one or more properties including glass transition temperature, coefficient of thermal expansion, thermal resistance, flame retardancy, dielectric constant, and dissipation factor. In addition, a method of preparing the phosphorus-containing compound and a resin composition comprising the phosphorus-containing compound are also disclosed.

The present invention relates to the alkylidene phosphonate esters of formula I wherein, R.sub.1 is selected from a group consisting of hydrogen or alkyl group; R.sub.2 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 Alzheimer's disease. ##STR00001##

Disclosed is a phosphorus-containing compound capable of serving as a flame retardant to be used in conjunction with other ingredients to make resin compositions, useful for fabricating such as a prepreg, a resin film, a resin film with copper foil, a laminate or a printed circuit board, having improved one or more properties including glass transition temperature, coefficient of thermal expansion, thermal resistance, flame retardancy, dielectric constant, and dissipation factor. In addition, a method of preparing the phosphorus-containing compound and a resin composition comprising the phosphorus-containing compound are also disclosed.