The metal‐free synthesis of 2‐aryl‐3‐arylmethylquinazolin‐4(3H)‐one is achieved through ionic liquid mediated and I2‐promoted tandem oxidative cyclocondensation of isatoic anhydrides with ...arylmethylamines as the common precursor for the 2‐aryl and 3‐arylmethyl moieties. Radical quenching experiments suggest a non‐radical mechanistic pathway and the operation under anaerobic condition confirms the essential role of I2 as the oxidant. Metal‐free synthesis, reduced reaction times to afford higher product yields, recyclability of the IL used as the reaction medium, and the feasibility of gram scale operation are some advantages.
Metal‐free access to 2,3‐disubstituted quinazolinones following a tandem oxidative cyclo‐condensation of istoic anhydrides with arylmethylamines mediated by BmimBF4 and Iodine is reported. The arylmethylamines serve as the common precursor for the C‐2 and N‐3 substituents.
Natural products have emerged as major leads for the discovery and development of new anti-cancer drugs. The plant-derived anti-cancer drugs account for approximately 60% and the quest for new ...anti-cancer agents is in progress. Anti-cancer leads have been isolated from plants, animals, marine organisms, and microorganisms from time immemorial. The process of semisynthetic modifications of the parent lead has led to the generation of new anti-cancer agents with improved therapeutic efficacy and minimal side effects. The various chemo-informatics tools, bioinformatics, high-throughput screening, and combinatorial synthesis are able to deliver the new natural product lead molecules. Plant-derived anticancer agents in either late preclinical development or early clinical trials include taxol, vincristine, vinblastine, topotecan, irinotecan, etoposide, paclitaxel, and docetaxel. Similarly, anti-cancer agents from microbial sources include dactinomycin, bleomycin, mitomycin C, and doxorubicin. In this review, we highlighted the importance of natural products leads in the discovery and development of novel anti-cancer agents. The semisynthetic modifications of the parent lead to the new anti-cancer agent are also presented. Further, the leads in the preclinical settings with the potential to become effective anticancer agents are also reviewed.
Communicated by Ramaswamy H. Sarma
Copper(I) catalysed oxidative conversion of imidazopyridines into N‐pyridinylamides has been achieved via tandem C−C and C−N bond cleavages under oxidative reaction conditions. The methodology has ...wide substrate scope and products were formed in good to excellent yields. This method is suitable for the oxidative conversion of both C‐3 functionalized as well as non‐functionalized imidazopyridines
Tandem C−C and C−N bond cleavage approach for the oxidative ring opening reactions of N‐fused imidazoles has been realized for the synthesis of N‐pyridinylamides.
Guanidinium species are highly basic and hence mostly exist in cationic state. Because these cations carry electron-deficient centers, they can be stabilized with the help of electron-donating ...ligands like
N
-heterocyclic carbenes. A few novel guanidinium cationic species stabilized by electron-donating ligands were designed and quantum chemically evaluated. It was shown that strong hydrogen bonds and tautomerism are the important characteristics of these species. Further, the possibility of donor→acceptor coordination interactions in these species have been explored between the electron-donating carbenes and the central guanidinium unit. The results suggest that the title compounds can be considered as ligand-stabilized guanidinium cations similar to the ligand-stabilized N
+
and N
3
+
centers.
Graphical abstract
An environmental friendly, NIS mediated oxidative cyclocondensation of 2-aminopyridine and aryl methyl ketone/cinnamaldehydes has been realized for the synthesis of 2-arylimidazo 1,2-apyridines and ...their 3-formylated products respectively. This one pot protocol involves simple reaction conditions, tolerates wide range of substrates and the products were formed in good to excellent yields.
Display omitted
Imidazopyridine scaffold has gained tremendous importance over the past few decades. Imidazopyridines have been expeditiously used for the rationale design and development of novel synthetic analogs ...for various therapeutic disorders. A wide variety of imidazopyridine derivatives have been developed as potential anti-cancer, anti-diabetic, anti-tubercular, anti-microbial, anti-viral, anti-inflammatory, central nervous system (CNS) agents besides other chemotherapeutic agents. Imidazopyridine heterocyclic system acts as a key pharmacophore motif for the identification and optimization of lead structures to increase medicinal chemistry toolbox. The present review highlights the medicinal significances of imidazopyridines for their rationale development as lead molecules with improved therapeutic efficacies. This review further emphasis on the structure-activity relationships (SARs) of the various designed imidazopyridines to establish a relationship between the key structural features versus the biological activities.
Communicated by Ramaswamy H. Sarma
Transition metal-free approaches for oxidative functionalization reactions have gained considerable importance over the past few decades. The recent updates on the use of TBAI ...(tetrabutylammoniumiodide) and TBHP (tert-butylhydroperoxide) as an efficient catalytic system for oxidative functionalization reactions on Csp
3
, Csp
2
, and Csp carbon have been described. The TBAI/TBHP synergistic combination proved to be a versatile catalytic condition for carrying out various oxidative transformations. Several reviews covering this topic have already been published. However, no comprehensive review covering the oxidative functionalization reactions on different hybridized carbon atoms was reported. In this review, we will cover oxidative reactions developed over the recent years promoted by TBAI/TBHP catalytic system. The mechanistic insights have described TBAI as the radical initiator which can lead to the generation of tert-butylhydroperioxideradical or itself gets oxidized to (hypo)iodite by TBHP.
The synthesis of Imidazo1,2-apyridine-3-carboxamides has been carried out by aminocarbonylation using chloroform as carbon monoxide surrogate. Reported protocol is simple, efficient, tolerates wide ...variety of substrates and the products were formed in good yields. The method can be exploited for the functionalisation of wide range of N-heterocycles with medicinal interest. The detailed mechanistic investigation of metal-catalyzed carboxamide preparation using Density Functional Theory (DFT) calculations has also been reported.
Display omitted
•The synthesis of Imidazo1,2-apyridine-3-carboxamides has been carried out by aminocarbonylation approach.•The DFT calculations validated the mechanism with the key transition states for carbonylation (TS1) and amination (TS2) with activation energy of 6.3 and 0.5 kcal/mol, respectively.•The 1H NMR studies have shown the presence of peak at δ 9.4–9.6 (3a-3p) which corresponds to the hydrogen attached to 5th carbon of the imidazopyridine.
Xanthine and its derivatives are considered an important class of N-heterocyclic purine compounds that have gained significant importance in medicinal chemistry. N-heterocyclic carbene (NHC) and ...N-coordinated metal complexes of xanthine and its derivatives have revealed a range of new possibilities for their use as therapeutic agents in addition to their established catalytic behavior. The metal complexes of xanthine and its derivatives have been designed and synthesized for the exploration of their potential therapeutic applications. These metal complexes based on the xanthine scaffold exhibited various potential medicinal applications including anticancer, antibacterial, and antileishmanial activity. The metal complexes of xanthine and its derivatives shall pave the way for the rational design and development of new therapeutic agents. In the present comprehensive review, we highlighted the recent advancements in the synthesis and medicinal applications of metal complexes based on N-heterocyclic carbene (NHC) derived from xanthine scaffolds.
The metal complexes of xanthine and its derivatives have been designed and synthesized for the generation of novel leads against various therapeutic disorders. The xanthine-based metal complexes obtained by the coordination of either N-heterocyclic carbonic carbon or through the N-coordination centre have been highlighted. Display omitted
•Metal complexes of xanthene and its derivatives with potential medicinal applications.•The metal coordination with xanthine occurs via carbonic or N-centre.•Xanthine serves as a flat structural motif for the rational design of novel leads.
