Lesley Dalton

Indole β-nucleophilic substitution. Part 7. β-Halogenation of indoles. Attempted intramolecular β-nucleophilic substitution of α-arylindoles

Intramolecular β-nucleophilic substitution of 2-aryl-1-phenylsulphonylindoles could not be achieved. N-Arylsulphonylation of 2-arylindoles with arylsulphonyl halides using phase-transfer conditions is accompanied by 3-halogenation in some cases; the proportion of 3-halogeno-arylsulphonyl-2-arylindole produced is greater with more electron rich 2-substituents supporting the view that the 3-halogenation is electrophilic in character.

Cyclic allylamine/enamine systems-6: Some reactions of 4-(indol-2-ylcarbonyl)-, 4-(indol-3-ylcarbonyl and 4-(indol- 3-ylmethyl)-1,2,5,6-tetrahydro-1 -methylpyridines

Abstract Indol-3-yl 1-methyl-1,2,5,6-tetrahydropyridin-4-yl ketone ( 1d ) can be isomerised to indol-3-yl l-methyl-l,2,3,4-tetrahydropyridin-4-yl- ketone but the protonated form of this enamine could not be cyclised to the indole α-position. Both indol-2-yl l-methyl-l,2,5,6-tetrahydropyridin-4-yl ketone ( 1c ) and its isomer ( 1d ) were cyclised to 5-membered ketones by mineral acid catalysed Michael-type addition of indole β- and α-positions respectively onto the unsaturated ketone systems. Ketone ( 1d )was transformed to l-acetylindol-3-yl 3-acetyl-l,4,5,6-tetrahydropyridin- 4 -yl ketone by hot acetic anhydride. Strong base treatment of indol-3-yl(l,2,5,6-tetrahydropyridin-4-yl) methane caused isomerisation of the double bond into conjugation with the indole rather than into the endocyclic enamine position.

Indole β-nucleophilic substitution. Part 5. Synthesis of the four isomeric 5H-pyrido [x,y-b] carbazole-5,11-diones and benzo analogues

The four isomeric 6H-pyrido[x′,y′:5,6]oxepino[3,2-b] indol-5(12H)-ones were transformed by alkali and air into the title pyridocarbazolequinones. A mechanism is proposed for these transformations.

The geometry at nitrogen in N-phenylsulphonyl-pyrroles and -indoles. The geometry of sulphonamides

The structures of 1-phenylsulphonylpyrrole, 1-phenylsulphonylindole, 4,5,6,7-tetrahydro-1-phenylsulphonylindole, and 1,2,3,4-tetrahydro-9-phenylsulphonylcarbazole have been determined by X-ray crystallography. The heterocyclic nitrogen is planar in some and pyramidal in others. A preferred geometry for the PhSO2N unit emerged from the structures; it is compared with available data for sulphonamides.

Indole β-nucleophilic substitution. Part 6. Photochemical transformations of oxepino[3,2-b]indolones

[2]Benzoxepino[4,3-b]indol-11-ones and pyrido[x′,y′:5,6]oxepino[3,2-b]indol-5-ones are transformed in the presence of light into indole-spiro(2-alkyl-2-aroyl)-3-ones. These, in the presence of air, in alcohol as solvent (or in some cases with alcoholic sodium alkoxide) are further converted into indolo[1,2-b]isoquinoline-6,12-diones and aza-analogues respectively.

Cyclising nucleophilic addition to azinium systems. Part 1. Reaction of 3-indol-2-ylpyridine, 3-indol-2-ylquinoline, 4-indol-2-ylisoquinoline and pyrido[3,4-a]carbazoles with acetic anhydride

Two pyrido[3,4-a]carbazoles were shown to react smoothly with acetic anhydride to give 1-acetyl-1,12a-dihydro[1,6]naphthyridino[4,6-aml]carbazol-11(12H)-ones. 3-Indol-2-ylquinoline and 3-indol-2-ylpyridine reacted in an analogous fashion though with further complications in the latter case. 4-Indol-2-ylisoquinoline gave E-2-acetyl-1-(1-acetylindol-2-ylmethylene)-2,3-dihydro-3-(2-oxopropyl)-1H-isoindole, the structure of which was determined by a detailed study of its 1H n.m.r. spectrum with decoupling, n.O.e. and relaxation time measurements.