Reaction of Mesoionic Thiazolones with m-Chloroperbenzoic Acid. Oxidative Dipole Extensions

Article abstract of DOI:10.1021/jo01312a009

The oxidation of anhydro-4-hydroxy-2,3,5-triarylthiazolium hydroxides (1) with m-chloroperbenzoic acid gave (in primary alcohols) 2,5-dialkoxy-2,3,5-triarylthiazolidin-4-ones (5) and N-aroylthiobenzanilides (6).Oxidation of anhydro-5-hydroxy-3-methyl-2-phenylthiazolium hydroxide (2) gave 3-methyl-2-phenylthiazolidine-4,5-dione (8) and N-formyl-N-methylthiobenzamide (9).The products arise from initial oxidations at the carbon atoms at position 5 of 1 and position 4 of 2, and transformation modes to the final products are discussed.These oxidations are the first examples of oxidative dipole extensions.