Thiolysis and Thionation of Carboxylic Acid Derivatives

Thiolysis and Thionation of Carboxylic Acid Derivatives. Thiolysis of imidates 

R C(OR )=NR , or their salts R C(OR )=NR X , respectively, has remained the method of choice for the synthesis of thionocarboxylates. 14-421 The starting materials can be obtained by addition of alcohols to nitriles, by alcoholysis of imido-chlorides, or by O-alkylation of amides. Dialkyl mono-(170) and bis-thiono-oxalates (171) are prepared in this way, in which case it is especially advantageous to use the imidates as free bases instead of their 

Thionation of esters and thiolesters with phosphorus pentasulphide yields thiono- or dithio-esters, e.g. (176).  

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