Die Umsetzung der 2‐Alkylthio‐Heteroaryliumsalze (I) mit Hydrazonen (II) führt unter Substitution zu AzoaIkyliden‐Heterocyclen (III).

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121ChemInform Abstract The title compounds (III) and their protonated analogues (V) are prepared as shown. Deprotonation of (V) is possible by addition of e.g. NaF. (III) absorb in the long-wave range of the visible spectrum (absorption maxima between 580 and 665 nm), but the quantum yields of the photolyses are low (10-4 to 7•10-4).