Transamidation of Carboxamides Catalyzed by Fe(III) and Water

Abstract

The highly efficient transamidation of several primary, secondary, and tertiary amides with aliphatic and aromatic amines (primary and secondary) is described. The reaction is performed in the presence of a 5 mol % concentration of different hydrated salts of Fe(III), and the results show that the presence of water is crucial. The methodology was also applied to urea and phthalimide to demonstrate its versatility and wide substrate scope. An example of its use is an intramolecular application in the synthesis of 2,3-dihydro-5H-benzo[b]-1,4-thiazepin-4-one, which is the bicyclic core of diltiazem and structurally related drugs (Budriesi, R.; Cosimelli, B.; Ioan, P.; Carosati, E.; Ugenti, M. P.; Spisani, R. Curr. Med. Chem. 2007, 14, 279-287). A plausible mechanism that explains the role of water is proposed on the basis of experimental observations and previous mechanistic suggestions for transamidation reactions catalyzed by transition metals such as copper and aluminum. This methodology represents a significant improvement over other existing methods; it can be performed in air and with wet or technical grade solvents.

Recent Advances in the Metal‐Catalyzed Activation of Amide Bonds

“…Al arge number of approaches have been developed for the transamidation reactionofp rimarya mides, under both stoichiometric and catalytic conditions. [83][84][85][86][87][88][89][90][91][92] However,t he transamidation of secondary or tertiarya mides has been less well-explored,o wing to the high stabilityo ft he amide bond, which is causedb yr esonance effects and unfavorable thermodynamics or thermoneutrality. [93,94] However,afew reports have managed to overcome the challenges associated with the transamidation of secondary amides.…”

Stable and Persistent Acyclic Diaminocarbenes with Cycloalkyl Substituents and Their Transformation to β‐Lactams by Uncatalysed Carbonylation with CO

“…[47] Their spectroscopic data were identical to those reported in the literature. [48] 1 Ha nd 13 CNMR spectra were recorded at ambient temperature with Varian NMRS-500 and MR-400 spectrometers operating at 500 and 400 MHz, respectively,f or 1 H. 77 Se NMR spectra were recorded with aV arian NRMS-500 spectrometer with neat dimethylselenide as external standard (d = 4ppm). [49] High-resolution (HR) ESI and APCI mass spectra were obtained with am icrOTOF time-of-flight mass spectrometer (Bruker Daltonics, Bremen, Germany) using an Apollo TM "ion funnel" ESI source.…”

Formamide Synthesis through Borinic Acid Catalysed Transamidation under Mild Conditions

“…However, these methodologies are significantly restricted to the use of expensive transition metals and high pressure of toxic gases. Alternatively, transamidation has been established by recent formylating methodologies reported by Williams,– Gamba‐Sánchez and other groups –. Unfortunately, despite of the advances achieved, most of the methods require excess amounts of activating reagents, high temperatures or extended reaction times to attain reasonable conversions along with a limited scope.…”