Towards Improved Alkoxyl Radical Precursors - The Synthesis of N-Alkoxy-4-(p-chlorophenyl)thiazole-2(3H)-thiones

Article abstract of DOI:10.1055/s-1997-5754

4-(p-Chlorophenyl)-3-hydroxythiazol-2(3H)-thione (3) can be prepared in good yields and in useful quantities from p-chloro acetophenone (1). O-Alkylation of the cyclic thiohydroxamic acid 3 via the respective potassium or the tetraethyl ammonium salts affords the esters 4. A slightly modified procedure allows the conversion of the acid 3 to the mixed anhydrides 5. The esters 4 and the anhydrides 5 are colorless to yellowish crystalline compounds which show a good shelf life. Visible light photolysis of the N-alkoxy derivatives 4e-g and reactive hydrogen donors affords substituted tetrahydrofurans 7 or tetrahydropyrans 8 via an alkoxyl radical pathway.