The chemistry of indole

The possibility of an electrophilic substitution reaction in the lilolidene series is shown. It is established that, when 2, 3-dimethyl-1, 7-trimethyleneindole (9, 10-dimethyl-9-lilolidene) is nitrated, the main product is the 5-nitro derivative with some of the 6-nitro isomer. The structure of the compounds obtained is established by the combined use of UV and NMR spectra. The conditions for the dehydrogenation of lilodines to lilolidenes are found. It is shown that the indoline system is dehydrogenated more readily than the tetrahydroquinoline system. The nitro compounds obtained are reduced to the corresponding amines by hydrazine hydrate in the presence of Raney nickel.