A green and efficient procedure was developed for the synthesis of bis(indolyl)methanes using ammonium niobium oxalate (ANO) NH₄[NbO(C₂O₄)₂(H₂O)_x]·nH₂O as the catalyst and water or glycerol as the solvent. Products were obtained in good to excellent yields under conventional heating (water, 50 °C) or under sonication (glycerol, 110 °C). In the reaction in water, the catalyst was easily reused for further reactions without loss of activity.

Organoselenium compounds have been successfully applied in biological, medicinal and material sciences, as well as a powerful tool for modern organic synthesis, attracting the attention of the scientific community. This great success is mainly due to the breaking of paradigm demonstrated by innumerous works, that the selenium compounds were toxic and would have a potential impact on the environment. In this update review, we highlight the relevance of these compounds in several fields of research as well as the possibility to synthesize them through more environmentally sustainable methodologies, involving catalytic processes, flow chemistry, electrosynthesis, as well as by the use of alternative energy sources, including mechanochemical, photochemistry, sonochemical and microwave irradiation.

We describe here a metal and base-free straightforward method to access arylselanyl anilines using glycerol as a solvent. Starting from N,N-disubstituted anilines and arylselanyl chloride, the protocol is general and was successfully applied to a sort of anilines with different substitution patterns in both the aromatic ring and the nitrogen atom. As desirable for a green synthetic procedure, the non-toxic, low volatile, renewable glycerol was used as a solvent at room temperature.