Process for the preparation of pyrrolidone-5,5-difosfonsyrer and water-soluble salts thereof

摘要

Pyrrolidone-5,5-diphosphonic acids having the formula OO HO PARALLEL PARALLEL OH ANGLE PP ANGLE HOOH ANGLE C ANGLE CH2N-R ¦¦ CH2---C=O wherein R is a member selected from the group consisting of hydrogen and alkyl having from 1 to 6 carbon atoms; as well as their water-soluble salts. The pyrrolidone-5,5-diphosphonic acids are excellent sequestering agents especially for alkaline earth metal ions. They are stabilizers for percompounds and are useful in the delaying of the setting times for gypsum. In addition, the compounds are useful as cosmetic preparations such as toothpastes and mouthwashes where they prevent formation of tartar and plaque and are useful in therapy in the treatment of diseases related to the abnormal deposition or dissolution of difficultly soluble calcium salts in the animal body.