The New Synthetic Method Of Indolizine Derivatives And Their Fluorescence Properties

Indolizine is a kind of heterocyclic compound which exhibit a variety ofbiological activities and is widely used in the field of medicine, photo-electricmaterials and dyes. The development of new synthetic method for indolizine not onlybenefits the basic research, but also has practical value. This thesis developed twokinds of synthetic methods, one for3-unsubstituted indolizines, the other one forpyrrolo[2,1,5-cd]indolizines. The molecular spectroscopy properties of these syntheticpyrrolo[2,1,5-cd]indolizines were also discussed in this thesis. The major results andconclusions were list as below:(1) A new synthetic method for3-unsubstituted indolizines through1,3-dipolarcycloaddition reaction using2,2,6,6-Tetramethyl-1-piperidinyloxy as oxidant wasdeveloped. The best reaction condition was investigated through screening the solvent,reaction temperature, base and the ratio of starting materials etc. The substrate scopesof starting materials were also examined under optimal reaction conditions, and anarray of3-unsubstituted indolizines were isolated. This method meets the requirementof green chemistry, because no any transitional metal was applied in thistransformation.(2) A new synthetic method for pyrrolo[2,1,5-cd]indolizines through palladiumcatalyzed C-H activation were developed. The3-unsubstituted indolizines werereacted with1,2-diaryl-acetylenes using oxygen gas as solo oxidant. The best reactioncondition was investigated through screening the catalyst loading, solvent, reactiontemperature, additive and the ratio of starting materials etc. The substrate scopes ofstarting materials were also examined, and an array of pyrrolo[2,1,5-cd]indolizineswere synthesized under optimal reaction conditions. The structures of somepyrrolo[2,1,5-cd]indolizines were confirmed through single crystal diffraction, whichrevealed the region selectivity of these new reactions. The reaction mechanism alsowas investigated through1H NMR experiments. The atom economy of this transformation was high, because the products only lost two hydrogen atomscompared with starting materials. Therefore, this method meets the requirement ofgreen chemistry.(3) The molecular spectroscopy properties of these syntheticpyrrolo[2,1,5-cd]indolizines were also examined. Compared to commercialfluorescence dyes (Alq3), the fluorescence intensity of these syntheticpyrrolo[2,1,5-cd]indolizines were higher. Furthermore, these syntheticpyrrolo[2,1,5-cd]indolizines were more stable than Alq3in solution under benchcondition.