Synthetic Approach for Novel Fluorine Substituted α-Aminophosphonic Acids Containing 1,2,4-Triazin-5-One Moiety as Antioxidant Agents

Novel fluorine substituted α-amino phosphonic acids containing 1,2,4-triazin- 5-one (6a-f) have been obtained from fluoroacylation of 6-(2′-amino-5′-nitrophenyl)-3-thioxo-1,2,4-triazin-5(4H)-one (1) followed by ammonilysis to give the corresponding 3-amino-derivative 3. Condensation of compound 3 with nitro/halogenated aromatic aldehydes yielded the Schiff bases 4. The simple addition of diethyl phosphonate to compound 4 produced the α-amino phosphonates 5. Acidic hydrolysis of compound 5 produced the fluorine substituted α-amino acids derivatives 6. Structures of the new compounds have been established with the help of elemental analysis and spectral measurements. Also, the products evaluated as antioxidants, where the fluorinated α-amino phosphonic acids 6 are more active than the other synthesized systems.