Synthesis and Solution Structure of 1 H ‐Benzo‐1,5‐diazepine Derivatives with a Perfluoroalkyl Side Chain

The reaction of perfluorinated 3,5‐dioxoesters with 1,2‐diaminobenzenes or 2,3‐diaminonaphthalenes afforded two types of 1 H ‐benzo‐1,5‐diazepine derivatives containing a perfluorinated side chain. 2,5‐Dihydro‐1 H ‐benzo‐1,5‐diazepin‐2‐ones were formed by cyclocondensation via the central keto and the ester group, whereas 1 H ‐benzo‐1,5‐diazepines resulted from cyclocondensation via the two keto groups. The tautomerism and isomerization of these compounds have been investigated by 1 H‐, 13 C‐, and 19 F‐ NMR spectroscopy. The 1,5‐diazepines appear in CDC l 3 solution as mixtures of two tautomeric forms, the enaminoimine I and diaminodiene II . In DMSO solution, besides I and II , two further species, III and IV , are formed by ( E / Z ) isomerization on the exocyclic C=C bond.