Heterogeneous catalytic solvent-free synthesis of 3,3,5-trimethyl cyclohexyl anthranilic acid esters via transesterification

The transesterification of anthranilates with both mixtures of cis and trans and pure trans 3,3,5-trimethyl cyclohexanol was studied using ‘calcium-oxide- and magnesium-oxide’-based catalysts under ‘solvent-free’ conditions. The catalysts were characterized by XRD, CO₂-TPD, BET-surface area, and FEG–SEM analysis. Pure calcium oxide was found to be the most effective heterogeneous catalyst. Pure ‘calcium-oxide’-based catalyst was recycled five times without appreciable loss in the catalytic activity. The TOF after five recycles was 10.7 mol/mol of catalyst/h. The study was further extended for the synthesis of new anthranilates. The synthesized pure esters have been characterized by UV–Vis, IR-, ¹H NMR-, and ¹³C NMR spectroscopies and mass spectrometry.