Iron/caffeine as a catalytic system for microwave-promoted benzamide formation
The amide bond is an essential unit in many drugs and polymers. The catalyzed oxidation of alcohols and amines is an effective method to form amides with limited undesired waste. Herein, we demonstrate the beneficial effect of microwave activation for this reaction. The benzamides were directly formed from alcohols and amine hydrochloride salts in short reaction times with yields up to 84% and TOFs (turnover frequencies) up to 33.6 h-1. Among the examined transition metals, only nontoxic and inexpensive FeCl2?·4H2O together with caffeine as a stabilizing ligand provided a uniquely efficient catalytic system for the transformation. Natural sources of caffeine were also evaluated under the amidation conditions.
Iron-catalyzed benzamide formation. Application to the synthesis of moclobemide
A convenient and user-friendly method to yield benzamides from primary and secondary amines and various benzylic alcohols in the presence of a cheap iron salt (FeCl2·4H2O) and tert-butylhydroperoxide (70% in water) as a stoichiometric oxidant is described. Control experiments indicated that this reaction might involve radical species. This method proved to be general, generating a family of 30 benzamides and was applied to the preparative synthesis of anti-anxiety drug moclobemide.
Iron-catalyzed benzamide formation. Application to the synthesis of moclobemide
A convenient and user-friendly method to yield benzamides from primary and secondary amines and various benzylic alcohols in the presence of a cheap iron salt (FeCl2$4H2O) and tert-butylhydroperoxide (70% in water) as a stoichiometric oxidant is described. Control experiments indicated that this reaction might involve radical species. This method proved to be general, generating a family of 30 benzamides and was applied to the preparative synthesis of anti-anxiety drug moclobemide.
MnO2 promoted sequential C-O and C-N bond formation via C-H activation of methylarenes: A new approach to amides
A novel and efficient approach for the synthesis of amides has been developed through manganese dioxide promoted nondirected C-H activation of methylarenes under mild reaction conditions employing N-chloroamines as effective coupling partners.