Sviripa V. New transformations of 2-aryl-4-dichloromethylen-5(4Н)-oxazolones and their analogues

The thesis is devoted to the investigation of reactivity of 2-aryl(heteryl)-4-dichloromethylene-5(4H)-oxazolones (chloro-containing azlactones) that resulted in development of the preparative synthesis of new derivatives of oxazole, imidazole, pyrimidine, oxazolo[4,5-d]pyrimidine, pyrimido[1,2-a]benzimidazole and other heterocyclic systems. It was found that continuous treatment of the chloro-containing azlactones by tiophenols, amines, and silver carbonate is a convenient method of synthesis of N-substituted 2-aryl(heteryl)-5-arylthio-l,3-oxazol-carboxami- des. Furthermore, based on cyclocondensation of the chloro-containing azlactones with o-aminothiophenol, it was shown that a series of 5-alkylthio-2-aryl-4-benzothiazol-2-yl-1,3-oxazoles can be obtained. It was also found that in interaction of the chloro-containing azlactones with benzamidine hydrochloride in a presence of triethylamine splitting of the azlactone ring takes place first and then intramolecular cyclization occurs leading to formation of substituted imidazolinones. By their heating in pyridine a unique recyclisation takes place with formation of key derivatives of less known oxazolo[4,5-d]pyrimidine.