Rhodanine-3-acetic acid based meta and para phenyl substituted novel derivatives: Synthesis, structural characterization and DFT study

{(5Z)-5-[3-(1,3-benzoxazol-2-yl)benzylidene]-4-oxo-2-thioxo-1,3-thiazolidin-3-yl}acetic acid and {(5Z)-5-[4(1,3-benzoxazol-2-yl)benzylidene]-4-oxo-2-thioxo-1,3-thiazolidin-3-yl} acetic acid two novel derivatives have been synthesized in good yields as pure products using Knoevenagel condensation and characterized through 1HNMR and C-13-NMR spectroscopic techniques. A DFT study has been performed to compare the experimental and theoretical results and to calculate different thermodynamic parameters. A strong correlation has been found between both experimental and theoretical parameters. Their ability to inhibit alpha-amylase was also examined in an in vitro investigation, particularly by calculating the percentage inhibition.