A selective and convenient method for the synthesis of 2-phenylaminothiazolines.

A series of 2-phenylaminothiazolines have been prepared from the corresponding N-(2-hydroxyethyl)-N'-phenylthioureas under mild reaction conditions using either thio-CDI (1,1'-thiocarbonyldiimidazole) or CDI (1,1'-carbonyldiimidazole) to promote the cyclization. This protocol provides the desired cyclization products in good yield with excellent selectivity. The scope and selectivity of this methodology are also described.