4741-67-7

3-Phosphonophthalide can be useful in the synthesis of 1-??[2-??amino-??1-??(4-??chlorophenyl)??ethyl]??-??3-??oxo-??1,??3-??dihydroisobenzofuran-??1-??ylphosphonic acid as a potential GABAB receptor antagonist. It is also useful in the preparation of phosphonic acid dichlorides.