Synthesis of Rizatriptan Analogues via the Fischer Indole Synthesis in the Presence of Sustainable Natural Deep Eutectic Solvents and Catalyst

Abstract

Abstract In this research, a facile and efficient protocol for the synthesis of rizatriptan analogues using natural deep eutectic solvents as an inexpensive, easily available, and environmentally friendly catalyst is developed. The reaction of various phenyl hydrazines (a–j) and 3,3-dimethoxy-N,N-dimethylpropan-1-amine (2) using natural deep eutectic solvents affords fused indole heterocyclic compounds under optimised conditions at 70°C to produce the desired products with excellent to good yields (77–89%) at short reaction times (1 h). This new facile methodology Compared with previous reactions, has the advantages of a reusable catalyst, short reaction times and simplicity of the product isolation.