Beiträge zur Chemie der Pyrrolpigmente, 50. Mitt.

摘要

Using fixed tautomeric structures of 3,4-dihydropyrromethenones and 2,3-dihydrobilatrienes-abc (N- and O-alkylation) a prevalence of the lactam and bis-lactam form over lactimes by several orders of magnitude could be deduced. Although there are complications arising from side reactions of the pyrrolidinone fragment, protonation equilibria provided valuable clues for this result which is nicely complemented by NMR-, IR and UV-VIS data.