Solvent-free multi-component synthesis of unsymmetrical bis(indolyl)alkanes with Lewis acid-surfactant-SiO₂ as nanocatalyst

Abstract

Herein we report the multicomponent synthesis of the bis(indolyl)methane derivatives in a ball mill. The reaction was carried out under solvent-free conditions using only the Lewis acid-surfactant-SiO₂ composite nanocatalyst (LASSC) prepared in situ. The unsymmetrical bis(indolyl) methane derivatives containing nitro or fluorine substitution with a yield of 72%–92% were obtained in a short reaction time. Within we verified that under the action of the combined catalyst of AlCl₃·6H₂O + SDS + SiO₂, the method of preparing unsymmetrical bis(indolyl)methane by mechanical grinding without solvent has obvious advantages. Finally, we inspected that the catalysis system can be used eight times without a significant decrease in activity.

Graphical Abstract

Keywords:

• Mechanochemistry
• LASSC catalyst
• Unsymmetrical bis(indolyl)methane
• solvent-free
• Ball mill

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was financially supported by the Engineering Research Center of Liupanshan, School of Chemistry and Chemical Engineering of Ningxia Normal University (HGZD20-09); the Research Award Fund for First-class Discipline Construction (Education Discipline) in Higher Education Institutions of Ningxia (NXYLXK2017B11); the Key Research Plan Projects of Ningxia (No. 2020BEB04019); the Ningxia Natural Science Foundation Project (No. 2020AAC03262); the National Natural Science Foundation of China (No. 21862013) and the Major Innovation Projects for Building First-class Universities in China’s Western Region (No. ZKZD2017003).