Sustainable Synthesis of 1,4-Disubstituted Piperazines Using Concentrated Solar Energy for Reductive Amination

Abstract

Reductive amination plays a crucial role in synthetic chemistry due to its widespread applications in pharmaceuticals, agrochemicals, specialty chemicals, and the general synthesis of amines. In the context of sustainable processes, our study harnessed concentrated solar radiation (CSR) as a renewable energy source to develop an energy-efficient reductive amination of aromatic aldehydes using sodium triacetoxyborohydride to synthesize 1,4-disubstituted piperazines. A range of piperazines, including pharmaceutical compounds such as Cinnarizine, Flunarizine, Clocinizine, and Teneligliptin intermediate, were synthesized on a gram scale. This method produced faster reactions (10–25 minutes), higher yields (78–94%), and a significant reduction in energy consumption (85–95%). Melting point, FT-IR, and ¹H NMR were used to characterize all produced compounds.