Synthesis, Structural Determination, and Antioxidant Activities of Acyclic and Substituted Heterocyclic Phosphonates Linearly Linked 4-hydroxy-2(1)-quinolinone.

The chemical reactivity of 3-[()-3-(dimethylamino)-2-propenoyl]-4-hydroxy-1-methy-2(1)-quinolinone () towards some phosphorus reagents was studied. The enaminone was cyclized into pyranoquinolinylphosphonate via treatment with diethyl phosphite in basic medium. However, its reaction with triethoxy phosphonoacetate gave the substituted oxopyranylphosphonate . Using the same reaction conditions, both thioxopyridinylphosphonate and oxopyranylphosphonate were produced via a reaction of enaminone with both diethyl 2-amino-2-thioxoethylphosphonate and diethyl vinylphosphonate, respectively, in low yields. In addition, the two novel oxopyridinylphosphonates and were obtained by treatment of enaminone with a diethyl cyanomethylphosphonate reagent. Two oaxathiaphosphininyl derivatives, and were obtained by treatment of the enaminone with -diethyl dithiophosphoric acid under different reaction conditions. Diazaphosphininyl and oxazaphosphininyl derivatives were obtained in excellent yields using a -phenylphosphonic diamide reagent under different reaction conditions. The treatment of the enaminone with phosphorus pentasulfide produced the non-phosphorylated product thioxothiopyranoquinolinone . Finally, the enaminone was turned into oxathiaphosphininyl using Lawesson's reagent. The possible reaction mechanisms of the formation of these products were discussed. The structures of newly isolated products were established by elemental analysis and spectral tools. The compounds were evaluated for their antioxidant activities.