Action of 1,2-diamines and o-aminophenols on 1-alkyl-3-carboxyindole-2-acetic acid anhydrides. Preparation of new ring systems

1-Alkyl-3-carboxyindole-2-acetic acid anhydrides (I) react with ethylenediamine and with o-phenylenediamine to give directly 10-alkylimidazo3,2:1′,2′]pyrido4,5-b]indol-5(1H)-ones (II) and 5,6-dihydro-5-alkyl-13H-indolo2′,3′:4,5]pyrido1,2-a]benzimidazol-13-one (V), respectively. However, anhydrides I react with o-aminophenol and with o-aminothiophenol to give carboxyindole-acetanilide derivatives IX, which can be cyclised to indolo2′,3′:4,5]pyrido2,1-b]benzoxazolone and indolo2′,3′:4,5]pyrido2,1-b]benzthiazolone (XI). Some derivatives of II and V were prepared to help in elucidating the structures.