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Updated: Aug 20, 2026

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
Published on: June 10, 2021
11-Methyl-2,3-benzodipyrrin-1-one
Raymond Bonnett1, Majid Motevalli, Fiona J Swanson
1Department of Chemistry, Queen Mary, University of London, Mile End Road, London E1 4NS, England. r.bonnett@qmul.ac.uk
Abstract:
The title compound {alternative names: 11-methyl-2,3-benzopyrromethenone and 3-[(1-methylpyrrol-2-yl)methylidene]-2,3-dihydro-1H-isoindol-1-one}, C(14)H(12)N(2)O, was prepared by the base-catalysed condensation of phthalimidine with 2-formyl-1-methylpyrrole; yellow orthorhombic crystals, space group Pbca, were obtained from ethanol. The molecule is almost planar, having Z(-)antiperiplanar geometry. The molecules are arranged in pairs with intermolecular hydrogen bonding between lactam functions. Comparison with literature values for polyalkyldipyrrin-1-ones shows that, apart from the local constraints of the benzene ring, the fused benzo ring has little effect on the molecular dimensions of the dipyrrin-1-one skeleton.
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