A Citrus Serenade:\nAn Improved Procedure for the Imine\nCondensation Reaction in Undergraduate Laboratories

The imine condensation reaction is commonly addressed\nin second\nsemester organic chemistry classrooms. With recent pushes toward green\nchemistry and developing safer reactions, there is a growing interest\nin attempting organic reactions in the presence of water or aqueous\nsolvents. The work discussed here provides an important update to\na previously reported laboratory experiment that utilizes freshly\nsqueezed fruit juices and water as the reaction solvents to compare\nthe reactivity of the imine condensation with respect to steric, electronic,\nand pH effects. Five different aromatic benzaldehyde derivatives are\nreacted with <i>n</i>-butylamine, <i>sec</i>-butylamine,\nand <i>tert</i>-butylamine in the presence of an aqueous\nsolvent. Students from multiple sections were able to successfully\nperform the updated reaction and analyze the products with <sup>1</sup>H NMR spectroscopy, calculate the percent conversion for each reaction,\nand analyze reaction trends. The conversion rates for this imine condensation\nlaboratory experiment greatly exceed those from our previously reported\nstudy which utilized organic solvents (J. Chem. Educ. 2023, 100 (11), 4456). Strategies\nfor implementation of this updated imine condensation project are\npresented.