Reactions with Betaine, XIV. Synthesis of Trifluoroacetylmethylide Trifluoroacetates from Betaines

Article abstract of DOI:10.1007/BF00809013

The reaction of trimethylammonium acetic acid betaine (1) with trifluoroaceticanhydride (TFA) yielding trifluoroacetyl-N-methylide can be extended to triethylammonium acetic acid betaine (2), 2-pyridiniumpropionic acid betaine (9) and N,N-dimethyl-piperidinium-2-carboxylate betaine (14).Trigonelline and 3-pyridiniumpropionic acid betaine (11), however, do not react in this way.It follows that the formation of such ylides is only possible if the methylene or methine group of the betaines are flanked by ammonium and carboxylate group. - Keywords: Trifluoroaceticanhydride; Triethylammonio trifluoroacetyl methylide trifluoroacetate; 1-Pyridinio-1-trifluoroacetyl ethylide trifluoroacetate; N,N-Dimethylpiperidinio-2-trifluoroacetyl-2-ylide trifluoroacetate