Synthesis of pyrroloquinoxalino-fused benzoxazepines and ester-containing iodopyridines

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2013
Yazıcı, Nuray Esra
Heterocyclic fused compounds have gained considerable attention for pharmaceutical applications since they show remarkable biological activities such as antitumor and/or anticancer activities. In particular, the synthesis of seven-membered ring embedded molecules is a challenging issue among organic chemists. Therefore, we have aimed to develop one-pot reaction for the synthesis of seven-membered-fused heterocyclic compounds. We have developed a new methodology for the synthesis of pyrrolo[2',1':3,4]quinoxalino[1,2-d][1,4]benzoxazepine derivatives starting from pyrrolo-substituted anilines and o-propargyloxybenzaldehydes. First of all, the synthesis of pyrrolo-substituted anilines was accomplished. Then, o-propargylation of benzaldehyde derivatives was performed. The reaction between pyrrolo-substituted anilines and o-propargyloxybenzaldehydes have afforded pentacyclic pyrroloquinoxalino-fused benzoxazepine molecules in one pot manner. For the synthesis of benzoxazepine derivatives, InCl3 was used as a Lewis acid catalyst in order to initiate electrophilic cyclization. In the second part of the study, the synthesis of ester-containing iodopyridines was performed in the presence of molecular iodine. In the course of this study, the synthesis of 5-iodopyridine-2,3-dicarboxylate was achieved through electrophilic cyclization of dimethyl 2-(prop-2-ynylamino)maleate in the presence of I2 and NaHCO3. The synthesized iodopyridine molecule was further functionalized by the Sonogashira coupling using terminal alkynes.