Ultrasound‐Assisted Synthesis of 3‐(Arylamino)‐1‐ferrocenylpropan‐1‐ones

A successful aza‐Michael addition of arylamines to a conjugated enone, acryloylferrocene, has been achieved by ultrasonic irradiation of the mixture of these reactants and the catalyst, i.e., montmorillonite K‐10. This solvent‐free reaction, yielding ferrocene containing Mannich bases, 3‐(arylamino)‐1‐ferrocenylpropan‐1‐ones, considered as valuable precursors in organic synthesis, has been performed by using a simple ultrasonic cleaner. Among 17 synthesized β‐amino ketones, three were new ones, and these were fully characterized by spectroscopic means. X‐Ray crystallographic analysis of three of these crystalline products enabled the insight into the conformational details of these compounds. All compounds were evaluated for their antibacterial activities against six Gram‐positive and five Gram‐negative strains in a microdilution assay. The observed promising antibacterial activity (with a MIC value of 25 μg/ml (ca. 0.07 μmol/ml) as the best result for almost all tested compounds against Micrococcus flavus) seems not only to be compound but also bacterial species‐specific.