Beilstein J. Org. Chem.2017,13, 825–834, doi:10.3762/bjoc.13.83
pyrrole esters is described. Efficient routes towards the synthesis of pyrrolopyrazinone, pyrrolotriazinone and pyrrolooxazinone have been developed. First, N-alkyne-substituted pyrrole ester derivatives were synthesized. Introduction of various substituents into the alkyne functionality was accomplished
, cyclization of N-alkyne-substituted methyl 1H-pyrrole-2-carboxylates with iodine only resulted in the formation of the 6-endo-dig cyclization product regardless of the substitution of the alkyne functionality.
Keywords: alkyne cyclization; pyrrole; pyrrolooxazinone; pyrrolopyrazinone; pyrrolotriazinone
][18][19][20][21][22]. In this article, we demonstrate for the first time the concept of the cyclization of N-alkyne-substituted pyrrole esters 7 (Figure 3) to provide a practical access to design pyrrolopyrazinone, pyrrolotriazinone, and pyrrolooxazinone derivatives.
Results and Discussion
The
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Graphical Abstract
Figure 1:
Structures of some natural products containing pyrazinone and aminotriazonone skeletons.