Browsing by Subject "indolizine"

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    Indolizines and pyrrolo[1,2- c ]pyrimidines decorated with a pyrimidine and a pyridine unit respectively
    (2015) Popa, Marcel Mirel; Georgescu, Emilian; Caira, Mino R; Georgescu, Florentina; Draghici, Constantin; Stan, Raluca; Deleanu, Calin; Dumitrascu, Florea
    The three possible structural isomers of 4-(pyridyl)pyrimidine were employed for the synthesis of new pyrrolo[1,2-c]pyrimidines and new indolizines, by 1,3-dipolar cycloaddition reaction of their corresponding N-ylides generated in situ from their corresponding cycloimmonium bromides. In the case of 4-(3-pyridyl)pyrimidine and 4-(4-pyridyl)pyrimidine the quaternization reactions occur as expected at the pyridine nitrogen atom leading to pyridinium bromides and consequently to new indolizines via the corresponding pyridinium N-ylides. However, in the case of 4-(2-pyridyl)pyrimidine the steric hindrance directs the reaction to the pyrimidinium N-ylides and, subsequently, to the formation of the pyrrolo[1,2-c]pyrimidines. The new pyrrolo[1,2-c]pyrimidines and the new indolizines were structurally characterized through NMR spectroscopy. The X-ray structures of two of the starting materials, 4-(2-pyridyl)pyrimidine and 4-(4-pyridyl)pyrimidine, are also reported.
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    Sydnone C-4 heteroarylation with an indolizine ring via Chichibabin indolizine synthesis
    (2016) Albota, Florin; Caira, Mino R; Draghici, Constantin; Dumitrascu, Florea; Dumitrescu, Denisa E
    The synthesis of sydnones heteroarylated at C-4 with an indolizine was achieved by Chichibabin (Tschitschibabin) indolizine synthesis starting from the corresponding sydnone-N-pyridinium bromides. The latter compounds were also transformed to sydnone-indolizines connected through a keto group at the C-4 position by refluxing them in 1,2-epoxybutane with an activated alkyne. The structures of the new compounds were assigned by FTIR, NMR spectroscopy and X-ray analysis.