Synthesis of methyl piperazinyl-quinolinyl α-aminophosphonates derivatives under microwave irradiation with Pd–SrTiO₃ catalyst and their antibacterial and antioxidant activities

Abstract

Novel methyl piperazinyl-quinolinyl α-aminophosphonates (MPQ-APs) (4a–4t) were synthesized by a one-pot reaction under microwave conditions, in the presence of a new Pd-SrTiO₃ catalyst. 4a–4t were prepared from the substrates methyl piperazinyl-quinolinyl carbaldehyde, selected aniline derivatives and diethyl phosphite. MPQ-APs were characterized by FT-IR, ¹H-NMR, ¹³C-NMR, 2D-NMR, ³¹P-NMR and high-resolution mass spectroscopy. The catalyst was prepared by a sequential reaction of Sr (II) nitrate, citric acid and Ti (IV) butoxide followed by reflux in the presence of Pd (II) nitrate. Pd-SrTiO₃ was characterized by FT-IR, P-XRD, SEM, BET, SEM-EDX and Raman spectroscopy techniques. The MPQ-APs were screened in vitro for antibacterial activity against four strains of bacteria and three yeast cultures. Compounds 4m and 4r showed good positive results for antimicrobial activity in ciprofloxacin and compounds 4m, 4r and 4f gave positive results for antioxidant activity.

Graphical Abstract

Keywords:

• Kabachnik Fields reaction
• palladium
• 2D-NMR
• antibacterial
• antioxidant

Additional information

Funding

The authors acknowledge the financial support of the Durban University of Technology (DUT).