Azoniaazulenes. Part 7. Functionalisation of 10H-azepino[1,2-a]indoles

Abstract

Direct functionalisation of azepinoindole 7 is described. Electrophilic attack by bromine, and by the Vilsmeier, Mannich, and Friedel–Crafts reagents gives 11-substituted azepinoindoles 8 and 11–14. From the bromo compound 8 an 11-lithioazepinoindole was obtained. With tert-butyllithium the azepinoindole 7 gave an allylic anion 36, which with trimethylsilyl (TMS) chloride gave the 8H-8-TMS derivative 16 and the 10H-8,10-bis-TMS derivative 17, for which an X-ray structure is provided. Alkylation of anion 36 gave mixtures of 8H-8-alkyl- and 10H-10-alkyl derivatives 18–25. while further lithiation of compound 16 and alkylation gave mixtures of 8,8- and 8,10-disubstituted compounds 26–33. Decomposition of azide 43 gave eight identified products 44, 45, 47–51 and 54.