10.1002/ejoc.201901776
European Journal of Organic Chemistry
COMMUNICATION
extended to synthesize 4-azolylpyrroles. (Scheme 8) To this end,
we carried out the interaction of isoxazolyl, 1,2,4-oxadiazolyl and
1,2,3-thiadiazolyl enamines 8a-е with isocyanides 2a-c. As a
result, we obtained new 4-azolylpyrroles in moderate yields. It is
worth noting that the formation of the pyrrole cycle was
accompanied by transesterification of ethyl esters into tert-butyl
group.
In addition, the reaction product of isoxazolyl enamine 8c and
isocyanide 2c decomposed during an attempt to isolate it from the
reaction mass. In the reaction of 1,2,3-thiadiazole enamine 8e
with isocyanide 3c the yield of pyrroles was found to be 0%. A
possible explanation for this fact may be the increased reactivity
of this enamine leading to the tar formation. The structure of 3-
azolylpyrroles is in acordance with spectral data and is
unambiguously confirmed by X-ray diffraction analysis of
compound 9b. (Figure 3)
Acknowledgments
This article was prepared with financial support from RUDN 5-100
program and the Russian Science Foundation (grant 18-73-
10099).
Keywords: isocyanide •enamine • enaminone • cycloaddition •
pyrrole • potassium tert-butoxide
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