Polymeric mesoions, 4. Synthesis of polymerizable mesoionic 4,6-dioxo-1,3-diazines derived from vinylbenzylmalonic acid

Vinylbenzylmalonic acid (4) was condensed with N,N'-diphenylformamidine (5a), N,N'-diphenylacetamidene (5b), S-propyl-1,3-diphenylisothiourea (6) and anilinopyridine (7) in the presence of dicyclohexylcarbodiimide (DDC). The resulting new mesoionic monomers 8a-d were polymerized with 2,2'-azoisobutyronitrile (AIBN) as an initiator and dodecanethiol as a chain transfer agent. The low molecular weight model compounds 5-benzyl-pyrido[1,2-a]pyrimidine-2,4-dione (9a) and 5-hexadecyl-4,6-dioxo-1,3-diphenyl-2-hexadecylthio-1,3-diazine (9b) were prepared for X-ray diffraction analysis and comparison of spectrospical data.