Monomers for adhesive polymers, 13.Synthesis, radical photopolymerization and adhesive properties of polymerizable 2-substituted 1,3-propylidenediphosphonic acids

摘要

A family of polymerizable 2-substituted-1,3-propylidenediphosphonic acids was successfully synthesized for an application in dental adhesives. Methacrylates as well as N-alkyl-acrylamides were prepared. Those monomers were synthesized in 4 to 6 steps and were fully characterized by ~1H NMR, ~(13)C NMR, ~(31)P NMR spectroscopy and by HRMS. In order to evaluate their reactivity, the copolymerization of each monomer with N,N'-diethyl-1,3-bis-(acrylamido)- propane (DEBAAP) in DMF was investigated by photo-DSC. Bis-(4-methoxybenzoyl)diethylgermanium (BMDG) was added as the photoinitiator to each mixture of acidic monomer/DEBAAP/DMF (2/3/5: mol/mol/mol). It was demon- strated that each monomer efficiently copolymerized with DEBAAP. Self-etching enamel-dentin adhesives containing these new diphosphonic acids were formulated and used to mediate a bond between the dental hard tissues (dentin and enamel) and a restorative material. According to both dentin and enamel shear bond strength measurements, 2-methacry- loyloxymethyl-1,3-propylidenediphosphonic acid 8, 2-[N-(2-methacryloyloxyethyl)-carbamoyloxymethyl]-1,3-propyliden- ediphosphonic acid 10a and 2-[N-(10-methacryloyloxydecyl)-carbamoyloxymethyl]-1,3-propylidenediphosphonic acid 10b were the best candidates to enter new formulations. Those diphosphonic acids were significantly more efficient regarding the etching of enamel than the 1,3-bis(methacrylamido)propane-2-yl dihydrogen phosphate 17, a monomer already used in some commercially available dental formulations.