A facile and versatile method for preparing N-substituted amides from alcohols and amides using a Brønsted acid and an alkali metal halide has been developed. Treatment of tertiary alcohols and amides in the presence of an alkali metal halide or methanesulfonic acid in trifluoroacetic acid at elevated temperature afforded the corresponding N-substituted amides in moderate to high yields. Tertiary alcohols with various functional groups such as ether, ester, imide, carbamate, and halogen groups were tolerated under these conditions. This method can be used for the efficient and practical synthesis of various N-substituted formamides without the use of unmanageable cyano compounds.
Key words
amides - alcohols - Brønsted acids - alkali metal halides - nucleophilic substitution
