SYNTHESIS OF DIHYDRO-1H-PYRROLO- AND TETRAHYDROPYRIDOINDOLES VIA A MODIFIED MADELUNG REACTION

Article abstract of DOI:10.1016/S0040-4020(01)88057-1

1-(2-Methylphenyl)lactams 9, having different electron -withdrawing groups at the benzylicposition, cyclize under the influence of sodium hydride or potassium tert-butoxyde.Depending on the ring size of the lactam moiety dihydropyrrolo- (10), tetrahydropyrido<1,2-a>indole (11), or dihydro-1H-1-benzazepine (12) derivatives are formed.Pyrrolo<1,2-a>indole 10c has been converted into the corresponding quione 15b.Starting from naphthaleneacetonitrile 20, prepared in 5 steps from 2,3-dichloronaphthoquinone, the 5,10-dioxo-1H-pyrollo<1,2-a>benzindole 22 is obtained upon treatment with base and subsequent oxidation of the protected hydroquinone function with ceric ammonium nitrate.