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.