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Tuesday, April 24 • 9:30am - 9:50am
Dihydropyrrole Synthesis From Novel Chalcones Via 6π Electrocyclizations

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Numerous 6π conjugated systems were observed during an electrocyclization-condensation reaction in order to understand the way freely resonating electrons behave in π-orbitals in the presence of withdrawing and donating substituents. We predict that when the 6π carbanion system contains with a withdrawing or deactivating residue, the density of the π-electrons will be delocalized, causing the π-electrons to be more organized and stabilizing the system. Under the notion that electrocyclic systems are thermodynamic, the stabilization of the carbanion system will decrease the reaction entropy, as well as hindering product formation, thus resulting in a decrease in yield under a specific time frame. In turn, We predict that donating or activating residues will contribute to a less stable, more electron dense and more entropic intermediate and these cause product formation to occur in relatively higher yields than the former case described. The electrocyclic-condensation of glycine-ethyl ester hydrochloride and chalcone derivatives with varying electronic substituents is the reaction of interest. In the reaction, the chalcone and glycine- ethyl ester will condense to form a secondary imine intermediate. In the same pot, this intermediate will undergo an electrocyclization in order to form a dihydro-pyrrole. Several novel alpha-substituted chalcones were synthesized in good to excellent yield using a variety of methods, some novel. It was found that the dihydropyrrole formed was dictated by the alpha-substituent.General alpha hydrogen chalcones formed C-N pi bonded dihydropyrroles, whereas other alpha-substituted chalcones generated N-H dihydropyrroles other dihydropyrroles are being developed and the results will be reported.

Tuesday April 24, 2018 9:30am - 9:50am PDT
202 Zeis Hall

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