Rapid And Efficient Synthesis Of 2,3-Dihydro-1H-1,5-Benzodiazepines Using Eco-Friendly Green Solvent Mixture (Glycerol: DMC)

Abstract

A novel eco-friendly methodology synthesizes 1 ,5-Benzodiazepines using a glycerol-dimethyl carbonate (DMC) solvent composite and ultrasound irradiation, addressing environmental limitations of conventional methods. The glycerol-DMC system serves as a biodegradable medium, utilizing glycerol's polarity and DMC's solvating properties. Sonochemical activation generates localized temperatures above 5000 K and pressures of ~1000 bar, accelerating reactions while ensuring uniform mixing. The method achieves high yields (93–96%) within 2-5 minutes, as glycerol stabilizes intermediates and DMC activates carbonyl groups. Ultrasound irradiation reduces energy consumption by 40–60% and enhances reaction efficiency, allowing Green solvent to be reused for three cycles. This protocol eliminates traditional solvents and enables solvent recovery via vacuum distillation. Spectroscopic analyses confirm product purity, Gram-scale syntheses maintain >90% yield under optimized conditions (40 kHz ultrasound, 7:3 glycerol:DMC ratio, 60°C). This approach establishes sustainable heterocyclic synthesis for pharmaceutical and agrochemical industries while supporting UN Sustainable Development Goals.