There are many attempts to replacing volatile organic compounds (VOCs) with water or various types of aqueous solutions. The most obvious are low cost, reduced flammability, reduced toxicity, and reduced environmental risk. Supercritical fluids, ionic liquids, immobilized solvents, solvent-less conditions, and the use of fluorous solvents and polyethylene glycol (PEG) may represent an increasingly significant choice for the replacement of traditional solvents in synthetic chemistry. The various reported methodologies have one or more disadvantages such as the requirement of: (i) stringent reaction conditions; (ii) prolonged reaction time; (iii) additional reagents/catalysts, high boiling solvents that are difficult to recover; (iv) costly, air sensitive, and toxic substances; and (v) lack of the ease of availability/preparation of the starting material/reagent, etc. We have focused our attention on the development of a green synthesis of benzothiazoles due to their wide ranges of application. We report an efficient synthesis of 2-substituted benzothiazoles/thiazolines in PEG in the absence of any acid/base catalyst.
