A 2H-Pyrano[3,2-a]indolizine Derivative

The indolizine and pyrano[3,2-a]indolizine skeletons of 10-ethyl-2-oxo-2H-pyrano[3,2-a]indolizine-3-carbonitrile, C₁₄H₁₀N₂O₂, are planar [mean deviations 0.003 (2) and 0.019 (2) Å, respectively]. The planar pyrone ring [mean deviation 0.009 (2) Å], fused at the 1- and 2-positions of the indolizine ring, is also almost coplanar with the indolizine ring [dihedral angle 2.3 (1)°]. The delocalized ring system of the indolizine skeleton extends to the fused 2-pyrone ring, resulting in a significant decrease in the bond-alternation characteristics of the 2-pyrone moiety.

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