Efficient synthesis of amides from secondary alcohols and CH₃CN promoted by Fe(NO₃)₃·9H₂O

The Ritter reaction is the most attractive method for synthesizing amides, and various acids have been used to promote this reaction. Compared to these acids, Fe(NO₃)₃·9H₂O is less toxic and costly, and it shows relatively high Lewis acidity and great catalytic activity. In this study, a simple and efficient protocol involving Fe(NO₃)₃·9H₂O as an additive for the synthesis of amides was developed. Various secondary alcohols could be reacted with CH₃CN to obtain their corresponding products, with CH₃CN being used as a reactant and solvent. This protocol was found to be applicable to a wide range of alcohols and nitrile substrates. In general, it was found that substrates containing electron-donating-groups offered the corresponding amides in good to excellent yields, while those with electron-withdrawing groups offered low to moderate yields. Meanwhile, this approach was scalable to the gram level, offering an attractive opportunity for further application in organic synthesis.