Synthesis of natural products with vinamidine system (1,5-diaza-1,3-pentadiene) is of interest for many reasons. They are found in red beets and other as the betacyanin pigments [1]. They are reactive towards electrophiles at C? and nucleophiles at C? and therefore they have tendency to undergo substitution instead of addition reactions. Reactions of vinamidinium salts with nucleophiles are of special preparative value: they lead e.g. to pyrazoles, oxazoles, pyrimidines, diazepines, quinolines, and quinolizines [2]. In this work we aimed to synthesis of some new vinamidinum salts using replacing NMe2 groups with aniline.
Methods:10 mmol of the appropriate vinamidinium salt and 28 mmol of the required aniline were heated under reflux for 6 h in 25 ml of methanol. The oily phase was separated from the reaction mixture and methanol was added to the mixture. After 30 min stirring, the resultant vinamidine was filtered off, washed with cold methanol and dried.
Results: The structures of all the newly synthesized compounds were confirmed by IR, 1H NMR, 13C NMR spectroscopy and as well as mass spectrometry.