A FACILE AND CONVENIENT SYNTHETIC METHOD FOR 2-BIS(TRIFLUOROACETYL)METHYLENE- AND 2-TRIFLUORO-ACETYLMETHYLENE-2,3-DIHYDRO-3-METHYLTHIAZOLES

摘要

2,3-Dimethylthiazolium iodides (1) reacted easily with trifluoroacetic anhydride in the presence of pyridine to give 2-bis(trifluoroacetyl)methylene-2,3-dihydro-3-methylthiazoIes (2) in excellent yields.Deacylation of 2 proceeded readily in moderate to high yields by acid catalyst such as silica gel and aqueous hydrochloric acid to afford the corresponding 2-trifluoroacetylmethylene-2,3-dihydro-3-methylthiazoles (3),which were smoothly reconverted into diacylated compounds (2) with trifluoroacetic anhydride.The highly poralized structure of 2 was also briefly discussed.