118428-73-2Relevant academic research and scientific papers
Pyrylium Compounds. 38. About the Ring Transformation of 2,4,6-Triarylthiopyrylium Salts by Acetic Acid Anhydride to Arylbenzenes and Thiobenzophenones
Zimmermann, Thomas,Fischer, Gerhard W.
, p. 35 - 43 (2007/10/02)
2,4,6-Triarylthiopyrylium salts 5 react in the presence of an appropriate condensing agent (sodium acetate, carbonate, methoxide, tert-butoxide or potassium acetate) with acetic acid anhydride to yield arylbenzenes 3 and thiobenzophenones 6.This ring transformation represents the first example of the conversion of the =S(+)- moiety into the thiocarbonyl group >C=S.Under the same conditions 3,5-dimethyl-2,4,6-triphenylthiopyrylium perchlorate (13) forms via -sigmatropic rearrangement the thiobenzophenone 15.The structure of the new compounds 6 was proved by spectroscopic methods as well as by degradation reactions.Thus, hydrogen peroxide converts 6a to the known benzophenone 4.Alkaline saponification gives the 2-hydroxy-benzophenone 8, whereas heating with hydrochloric acid causes a selective cleavage of the acetoxy group to the 2-hydroxy-thiobenzophenone 7.
