Synthesis of fluorine-containing alkyl 2-cyano-3-oxocarboxylates. Reactions with nucleophiles

Abstract

Fluorine-containing alkyl 2-cyano-3-oxocarboxylates were synthesized for the first time by the reaction of ethyl cyanoacetate with fluorine-substituted carboxylic acid halides or alkyl earboxylates. The reactions with hydrazine hydrate, phenylhydrazine, and o-phenylenedianaine give hydrazinium (ammonium) enolates or products of acid decomposition.Key words: alkyl perfluoro-2-cyano-3-oxocarboxylates, acylation, condensation, hydrazinc hydrate, phenylhydrazine, o-phenytenediamine, salt formation, acid decomposition.Ethyl 2-cyanoacetoaeetate can be obtained by the reactions of sodium ethyl acetoacetate with C1CN ! or of ethyl cyanoacetate (1) with ketene. 2,3 The most common and convenient method for the synthesis of this 2-cyano-3-oxo ester and its nonfluorinated analogs is acylation of ester ! with the corresponding acid chlorides 4.5 and anhydrides. 6 Ethyl 2-cyanoacetoacetate reacts with NH 3, EtNH2 ,I and semicarbazide 4 to give azomethines in the form of [3-aminocrotonic acid derivatives. Literature data on the synthesis of fluorine-containing alkyl 2-cyano-3-oxocarboxytates and their reactivity are lacking.The goal of the present investigation is to obtain new esters of fluorinated 3-oxocarboxylir acids. Among the representatives of this class and their derivatives, many substances were found to possess useful properties for practical purposes. Ethyl-perfluoro=2=cyano-3-oxocarboxylates and their copper chelates were synthesized for the first time, and their reactions with N-nucleophiles (hydrazine hydrate, phenylhydrazine, and o-phenylenediamine) were studied.