Perfluorocarboxylic acids, synthesis

Scheme 11 indicates the usefulness of salts derived from Wittig ylide reagents and anhydrides of perfluorocarboxylic acids in the synthesis of fluorinated alkenylphosphonic diesters (127), often together with (epoxyalkyl)phosphonic diesters (128)(Rf = CF3 or... 

Lopyrev et al. developed an original method for the synthesis of 3-perfluoroalkyl-5-amino-l,2,4-triazoles 79 in nearly quantitative yields based on the cyclization of perfluoroacylaminoguanidines that in their turn were obtained in good yields (60-81 %) from hydrazides of perfluorocarboxylic acids and S-methylisothiourea [78]. 

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