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Updated: Aug 6, 2026

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
14:11

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach

Published on: June 10, 2021

Hydrogen-Bonding Effects at Pyrrolic NH Sites: Optical Properties of Benzo[a]indolo[2,3-c]carbazole Derivatives

Ryota Okubo1, Osamu Iwanaga1,2, Chinmay H Pawar1

  • 1Department of Chemical Science and Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, Japan.

Chemistry (Weinheim an Der Bergstrasse, Germany)
|July 24, 2026
PubMed

Keywords:
X‐ray diffraction analysisazahelicenefluorescencehydrogen‐bondsolvent effect

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Basicity of Heterocyclic Aromatic Amines

Heterocyclic amines, where the N atom is a part of an alicyclic system, are similar in basicity to alkylamines. Interestingly, the heterocyclic amine having a nitrogen atom as part of an aromatic ring has much less basicity than its corresponding alicyclic counterpart. For this reason, as presented in Figure 1, piperidine (pKb = 2.8) is significantly more basic than pyridine (pKb = 8.8).
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Frost Circles for Different Conjugated Systems

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