Azepine is an unsaturated heterocycle of seven atoms, with a nitrogen replacing a carbon at one position.
The atoms are numbered starting with the nitrogen. The 1H-azepine isomer shown above is an unstable red oil at -78°C and rearranges on contact with acid or base to 3H-azepine with two hydrogen atoms attached to the third carbon.Römpp Lexikon
See also Azepane Benzazepines Diazepine Oxepin Borepin
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