Pyrido[3,2,1-jk]carbazoles 1, synthesized from carbazoles and alkyl- or arylmalonates, gave regioselective electrophilic substitution reactions at position 5 such as chlorination to 5-chloro derivatives 2, nitration to 5-nitro compounds 3 or hydroxylation to 5-hydroxy derivatives 4. 5-Hydroxy compounds 4 gave upon treatment with strong bases ring contraction to 5, 6 or the ring opening product 7. Exchange of the chloro group in 2 with azide or amines gave the corresponding azides 8 and the 5-amino derivatives 9 and 10. Alkylation of 1 with benzyl chloride or allyl bromide resulted in the formation of 5-C-alkylated products 11 together with 4-alkyloxy derivatives 12.
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