107344-55-8Relevant academic research and scientific papers
Interrupted Pummerer Rearrangement: Capture of Tricoordinate Sulfur Species Generated under Pummerer Rearrangement Conditions
Bates, Dallas K.,Winters, R. Thomas,Picard, Joseph A.
, p. 3094 - 3097 (2007/10/02)
A new approach to fused N,S-heterocycles is described.Treatment of N-(2-(alkylsulfinyl)phenyl)pyrroles (5) under conditions which typically promote reaction at the carbon α to the sulfoxide group (i.e., the TFAA-initiated Pummerer rearrangement) produces selectively either pyrrolobenzothiazole (9) or 1-(trifluoroacetyl)pyrrolobenzothiazole (7).It is suggested the process occurs by reaction of the pyrrole nucleus at sulfur of the corresponding O-trifluoroacetylated sulfoxide 1 producing an intermediate S-alkylpyrrolobenzothiazolium salt 3.Nucleophilic displacement of the S-alkyl substituent by the trifluoroacetate counterion liberates pyrrolobenzothiazole, which may undergo trifluoroacetylation in the presence of excess TFAA.This approach to sulfur activation for intramolecular cyclizations is superior to other methods (usually involving positive halogen and a sulfide) since polyhalogenation and the instability of derivative halopyrroles are avoided.
Intramolecular Capture of Pummerer Rearrangement Intermediates. I. Synthesis of Pyrrolobenzothiazines
Bates, Dallas K.,Winters, R. Thomas,Burnell, A. Sell
, p. 695 - 699 (2007/10/02)
Treatment of 1-(2-alkylsulfinylphenyl)pyrroles with trifluoroacetic acid in refluxing toluene gives 4-substituted pyrrolobenzothiazines in good yield when the alkyl group bears an electron withdrawing substituent on the α-carbon.In the absence
