Cleavage of Diethyl Chromonyl α-Aminophosponate with Nitrogen and Carbon Nucleophiles: A Synthetic Approach and Biological Evaluations of a Series of Novel Azoles, Azines, and Azepines Containing α-Aminophosphonate and Phosphonate Groups

Facile One-Pot Three Component Synthesis, Characterization, and Molecular Docking Simulations of Novel α-Aminophosphonate Derivatives Based Pyrazole Moiety as Potential Antimicrobial Agent

An efficient method has been developed for the synthesis of novel α-aminophosphonates (AAP) (3 a-m) through a one-pot three-component reaction of 1,3-disubstituted-1H-pyrazol-5-amine, aromatic aldehydes, and phosphite using lithium perchlorate as catalyst. All newly synthesized compounds were characterized via different spectroscopic techniques. The synthesized compounds' mode of action was investigated using molecular docking against the outer membrane protein A (OMPA) and exo-1,3-β-glucanase, with interpreting their pharmacokinetics aspects. The results of the antimicrobial effectiveness of these compounds revealed a broad spectrum of their biocidal activity and this in-vitro study was in line with the in- silico results. Additionally, it has been demonstrated that these compounds exhibited a minimum inhibitory concentration (MIC) with significant activity at low concentrations (7.5-30.0 mg/mL). Further, the radical scavenging (DPPH* ) activity of the synthesized compounds fluctuated, with compounds 3 h, 3 a, and 3 f showing the highest antioxidant activity. Overall, the formulated compounds can be employed as antimicrobial and antioxidant agents in medical applications.

Three-Component Reaction of 3-Formyl-6-Methylchromone, Primary Amines, and Secondary Phosphine Oxides: A Synthetic and Mechanistic Study

A fast, mild, and efficient catalyst-free approach has been developed for the synthesis of chromonyl-substituted α-aminophosphine oxides by the three-component reaction of 3-formyl-6-methylchromone, primary amines, and secondary phosphine oxides at ambient temperature. Carrying out the reaction with aliphatic amines or aminoalcohols at a higher temperature (80 °C), phosphinoyl-functionalized 3-aminomethylene chromanones were formed instead of the corresponding chromonyl-substituted α-aminophosphine oxides. No reaction occurred when 3-formyl-6-methylchromone and secondary phosphine oxides were reacted with aromatic amines in the absence of any catalyst. Applying a basic catalyst, the formation of the phosphinoyl-functionalized 3-aminomethylene chromanones was observed; however, the reaction was not complete. Detailed experimental and quantum chemical studies were performed to study the transformation. Moreover, the in vitro cytotoxicity of phosphinoyl-functionalized 3-aminomethylene chromanones was also investigated in three different cell lines, such as human lung adenocarcinoma (A549), mouse fibroblast (NIH/3T3), and human promyelocytic leukemia (HL60) cells. Several derivatives showed modest activity against the human promyelocytic leukemia (HL60) cell line.

Synthesis of Chromone-Related Pyrazole Compounds

Chromones, six-membered oxygen heterocycles, and pyrazoles, five-membered two-adjacent-nitrogen-containing heterocycles, represent two important classes of biologically active compounds. Certain derivatives of these scaffolds play an important role in medicinal chemistry and have been extensively used as versatile building blocks in organic synthesis. In this context, we will discuss the most relevant advances on the chemistry that involves both chromone and pyrazole rings. The methods reviewed include the synthesis of chromone-pyrazole dyads, synthesis of chromone-pyrazole-fused compounds, and chromones as starting materials in the synthesis of 3(5)-(2-hydroxyaryl)pyrazoles, among others. This review will cover the literature on the chromone and pyrazole dual chemistry and their outcomes in the 21st century.