Oxalic acid dihydrate: L-proline (LTTM) mediated synthesis of 2-substituted benzothiazole derivatives

An efficient, selective and green route for the synthesis of 2-substituted Benzothiazole derivatives (3a-i) developed by the reaction of 2-aminothiophenol (1) and various aromatic aldehydes (2a-i) using oxalic acid dihydrate: proline low transition temperature mixture (LTTM) as green reaction medium at room temperature. The attractive features of this protocol are simple reaction conditions, recyclability and reusability of the LTTM, good product yield and easy workup procedure. The method is operationally simple and ecofriendly.