35237-08-2Relevant academic research and scientific papers
Pyrylium Compounds. 34. 2-Acetonyl-2H-thiopyrans from 2,4,6-Triarylthiopyrylium Salts
Zimmerman, Thomas,Fischer, Gerhard W.
, p. 573 - 581 (2007/10/02)
2,4,6-Triarylthiopyrylium salts 4 react with acetone in the presence of amine salts of weak acids (e.g. piperidine acetate) to give the hithero unknown 2-acetonyl-2H-thiopyrans 5, the structure of which was established by spectroscopic methods.Depending on the nature of the amine salts used, the enamine 6 or the enol 7 of acetone may function as attacking nucleophile.Using the 2,4,6-triphenyl derivative 5a as model compound, some typical reactions of 2-acetonyl-2H-thiopyrans were studied.With 2,4-dinitrophenylhydrazine, semicarbazide and thiosemicarbazide, the carbonyl derivatives 10a-c are formed.Hydrogen peroxide in acetic acid affords the S,S-dioxide 11.Methanolic sodium methoxide or sodium hydroxide in aqueous ethanol give rise to a ring transformation yielding 1,3,5-triphenylbenzene (12) and 2,4,6-triphenylacetophenone (13).Under similar conditions, benzaldehyde reacts with 5a to give 2',4',6'-triphenylchalcone (14).Perchloric acid regenerates from 5a the initial thiopyrylium perchlorate 4a.
