Isatogens (3-oxo-3H-indole 1-oxides) possess interesting biological properties and development of a general method to construct these derivatives has now been developed. Indolines (2,3-dihydroindoles) and isatogens have been prepared in an efficient route starting from indoles substituted in position 2. Reduction of the 2-substituted indoles was performed with tin and hydrochloric acid to give racemic indolines, which were converted to isatogens by 3-chloroperoxybenzoic acid (m-CPBA).

Cyanoacetic acid was activated with acetic anhydride and when heated this reagent reacted with a variety of both activated and deactivated pyrroles, indoles and aniline derivatives.

Various synthetic applications of 3-(cyanoacetyl)indoles, as well as syntheses of some related indoles, have been investigated. Diethyl 2-(1H-indol-3-yl)-2-oxoethylphosphonate and a methyl derivative thereof have been prepared in one step from indole. Moreover, it was demonstrated that 3-(cyanoacetyl)indoles are useful starting materials for the preparation of for example 3-(1H-indol-3-yl)-3-oxopropanamides, 3-heteroarylindoles or 3-heteroaroylindoles.