No abstract

Novel α‐(acyloxy)‐α‐(quinolin‐4‐yl)acetamides were synthesized by the Passerini three‐component reaction between an isocyanide, quinoline‐4‐carbaldehyde, and arenecarboxylic acids in H2O. The reactions were carried out in one pot at room temperature with quantitative yields.

Heterocyclic compounds have gained immense importance because of their low resonance energy and strong hydrogen-bonding abilities, which provide good catalytic potential in a variety of organic transformations. Herein an unexpected metal-free catalytic performance of heteroaromatic aldehydes has been reported. Accordingly, a unique method for the synthesis of new scaffolds of peptidomimetic compounds, α-aminophosphonates has been developed, which was difficult using previous methods. The aerobic auto-oxidation of heteroaromatic aldehydes acts as a driving force for the coupling of aromatic N-benzylamines and hydrophosphoryl compounds according to a one-pot, metal-and solvent-free procedure. Heteroaromatic aldehydes, in addition to their individual ability to promote selective radical reactions through the auto-oxidation process, can provide hydrogen bonding frameworks at different stages of the reaction and thereby change the reaction pathways and induce new activities and selectivities, which unveiled their other important catalytic features. We believe that this highlights the catalytic potential of heteroaromatic aldehydes, which may offer an opportunity to change the traditional harsh conditions necessary to generate alkyl radicals.[a] Dr. reaction, as monitored by TLC, the reaction mixture was allowed to cool at room temperature. The mixture was then extracted with ethyl acetate three times and dried over MgSO 4 , filtered, and concentrated under reduced pressure. 4 5 6 7 8

Kabachnik-Fields reaction between an amine, quinoline-4-carbaldehyde, and a phosphite in the presence of the prepared silica nanoparticles from rice hulls (silica NP; ca. 42 nm) proceeds smoothly to afford the corresponding α-aminophosphonates in high yields. The reactions were carried out in one pot and under solvent-free conditions at 50-80 ˚C.