Synthesis of 5H-pyrido[2,3-c]-2-benzazepines

Article abstract of DOI:10.1002/ardp.19943270407

The title compounds can be obtained by two different ways: Ring closure of 2-benzazepine enaminonitrile 1 and the C₂-building blocks 2, 7 and 8 gives rise to the title compounds 6, 9 and 10. - The second way starts with Wolff-Kishner-reduction of the 2-amino-3-benzoylpyridines 16a,b to the 2-amino-3-benzylpyridines 18a,b. Benzoylation of 18a,b leads to the dibenzoylated compounds 20 and 21, respectively, which can be transformed to the monobenzoylated pyridines 22 resp. 23. Applying the Bischler-Napieralski-reaction on 22a,b and 23a,b leads to the 5H-pyrido[2,3-c]-2-benzazepines 24a,b and 25a,b. By means of ¹H-, ¹³C- and ¹⁵N-NMR-data it is demonstrated that ethyl benzoylcyanacetimidate (12a) exists as benzoylketene-O,N-acetal 12a AE.