A sustainable process for gram-scale synthesis of stereoselective aryl substituted ( E )-2-thiocyanatoacrylic acids

We have developed a new, simple and sustainable process for stereoselective synthesis of aryl substituted (E)-2-thiocyanatoacrylic acids by nucleophilic substitution and Knoevenagel condensation involving chloroacetic acid, ammonium thiocyanate and aromatic aldehydes at room temperature. The selectivity was controlled by appropriately choosing aromatic aldehydes. The influence of intramolecular hydrogen bonding of 3-(2-hydroxyphenyl)-2-thiocyanatoacrylic acid involves the formation (Z) isomers. The salient features of the present protocol are mild reaction conditions, excellent yield, easy filtration, clean reaction profiles and applicability towards gram-scale synthesis. Importantly, the synthetic application of this protocol leads to the emergence of various biologically important compounds. A novel steroselective and gram-scale synthesis of aryl substituted (E)-2-thiocyanatoacrylic acids from chloroacetic acid, ammonium thiocyanate and substituted aromatic aldehydes in the presence of ammonium acetate. The selectivity is controlled by the chosen aromatic aldehydes.