Facile Synthesis of N-Sulfonylcyclothioureas in Water

A sequential one-pot synthesis of N-sulfonylcyclothioureas from N-monosulfonyl diamines, CS2 and chloroacetic acid at room temperature in water is described. In the absence of highly toxic thiophosgene and organic solvents, this method is environmentally benign. Simple reaction conditions, easy purification of the products, good yields and thioglycolic acid as the useful byproduct are also important attributes of this methodology. The plausible mechanism including tandem reactions is proposed.