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Updated: Jun 12, 2026

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
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Published on: June 10, 2021

Pyrrole Annulation Controls Protonation-Induced Topology Switching in π-Extended Core-Modified Figure-of-Eight

Sumit Sahoo1, Sergio Moles Quintero2, Mercedes Alonso2

  • 1School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A/2B Raja S.C Mullick Road, Jadavpur, Kolkata, West Bengal 700 032, India.

Organic Letters
|June 11, 2026
PubMed

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Cycloheptatriene is a neutral monocyclic unsaturated hydrocarbon that consists of an odd number of carbon atoms and an intervening sp3 carbon in the ring. The three double bonds in the ring correspond to 6 π electrons, which is a Huckel number, and therefore satisfies the criteria of 4n + 2 π electrons. However, the intervening sp3 carbon disrupts the continuous overlap of p orbitals. As a result, cycloheptatriene is not aromatic.
Removing one hydrogen from the intervening CH2 group with both...
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