Samojlenko V. Reaction of isoindolo[2,1-a]quinazolines with dienophiles

The dissertation is devoted to the investigation of the reaction of the 6-methyl-5,6-dihydroisoindolo[2,1-a]quinazoline-5-one with dienophiles under different conditions and reagent ratio. Assumption about the activity of 6a and 11 positions of 10p-electron aromatic 6-methyl-5,6-dihydroisoindolo[2,1-a]quinazoline-5-one system in the Diels-Alder reaction and Michael addition was confirmed experimentally. Annelation of quinazoline moiety to isoindole system was revealed not to be almost influential on the attack direction of the dienophiles but to cause subsequent unexpected transformation of the first-formed adducts. Novel rearrangement was discovered: reaction of the 6-methyl-5,6-dihydroisoindolo[2,1-a]quinazoline-5-one with cyclic dienophiles having double bond gave unexpected rearrangement adducts in the reagent ratio 1:1 under conditions of thermodynamic control. Their structure was proved by the X-ray analysis. A mechanism of the rearrangement was proposed and confirmed. Intermediates of the reaction were isolated under conditions of kinetic control. It was proven for the first time that the formation of the rearrangement adducts goes through intermediate Diels-Alder adducts and goes consecutively: endo-adduct -> exo-adduct -> rearrangement adduct. The products of the reaction of 6-methyl-5,6-dihydroisoindolo[2,1-a]quinazolin-5-one with maleinimides in the ratio 1:2 under conditions of thermodynamic control were adducts 1:2 in exo-configuration. Such novel heterocyclic system is the first example of stable tricyclic 7-azabenzonorbornenes. Their structure was established by the X-ray analysis. A mechanism of their formation was proposed and confirmed experimentally. The 6-methyl-5,6-dihydroisoindolo[2,1-a]quinazolin-5-one was found to react with dimethyl acetylenecarboxylate in Michael addition manner. The obtained Michael adduct was discovered to have moderate bactericidal activity.