Comparative biological study between quinazolinyl–triazinyl semicarbazide and thiosemicarbazide hybrid derivatives

Molecular Diversity - Practical synthesis and biological activities of quinazolinyl–triazinyl semicarbazides (10a–j) and quinazolinyl–triazinyl thiosemicarbazides (11a–j)...     

Palladium catalyzed domino C-H activation strategy: An access to 9- fluorenones

Palladium catalyzed domino C-H functionalization reaction of arylaldehyde with dihaloarene has been developed to access 9-flourenone molecules. Bidentate ligand assisted strategy, single step reaction, high yield and excellent functional group tolerance make this method concise and effective for the synthesis of 9-flourenone. In addition, proposed method has been successfully employed to synthesise Tilorone in gram scale.     

Synthesis of indenoquinolinone through aryne-mediated Pd(II)-catalysed remote C–H activation

Research on Chemical Intermediates - Indenoquinolinones have been synthesized from 2-haloquinoline-3-carbaldehyde through Pd-mediated simultaneous C–H (aldehyde) and C–X bond...     

Synthesis and Antibacterial Studies of Some Novel 2-(Coumarin-3-yl)-5-mercapto-1,3,4-oxadiazoles Containing 2,4,6-Trisubstituted s-Triazine Derivatives

A new series of 2-(coumarin-3-yl)-5-mercapto-1,3,4-oxadiazoles based on various aryl thiourea/ureas incorporating a 1,3,5-s-triazine moiety is reported. The components of this series have been obtained by the reaction of cyanuric chloride (1) with 2-(coumarin-3-yl)-5-mercapto-1,3,4-oxadiazole (2). The prepared 2-{(coumarin-3-yl-1,3,4-oxadiazolyl)-5-thio}-4,6-dichloro-s-triazine (3) was subsequently treated with morpholine (4) to form 2-{(coumarin-3-yl-1,3,4-oxadiazolyl)-5-thio}-4-(morpholino)-6-chloro-s-triazine (5). This was further treated with various substituted aryl urea/thioureas (6a–k/7a–k) to afford the title compounds 8a–k and 9a–k, which were and tested for their antibacterial activity (MIC) against different microorganisms. The structures of the novel synthesized compound have been established on the basis of ¹H NMR and FT-IR data together with elemental analysis.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Combination of bioactive moieties with different heteroatom(s): Application of the Suzuki cross‐coupling reaction

Two series of thiophene/benzothiophene‐linked quinolinyl oxadiazoles condensed to the substituted N‐benzothiazolyl acetamides have been synthesized via the Suzuki cross‐coupling reaction. The ester derivative of 6‐bromo‐substituted quinoline was reacted via the Suzuki cross‐coupling reaction with commercially available (benzo)thiophen‐2‐ylboronic acid at optimized temperature in 1,2‐dimethoxy ethane and water in the presence of potassium carbonate and palladium tetrakis. The resulting derivatives were then hydrazinolized using 99% hydrazine hydrate followed by cyclization using carbon disulfide in ethanolic KOH to furnish the corresponding oxadiazoles, which were then condensed with various substituted 2‐chloro‐N‐benzothiazolyl acetamides to produce the final scaffolds involving a unique combination of four heterocycles to be examined for their antimicrobial activity against two Gram‐positive bacteria (Staphylococcus aureus and Bacillus cereus), three Gram‐negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae), and two fungal species (Aspergillus niger and Candida albicans). The investigation of biological screening data revealed that the majority of the compounds tested have demonstrated excellent activity (minimum inhibitory concentrations; 6.25–50 µg/mL) against most of the microorganisms as compared with the standard and hence they warrant more consideration as prospective antimicrobial agents. New products ( 9a–10i ) were characterized by physicochemical, elemental, and spectral (IR, ¹H NMR, and ¹³C NMR) data. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:399–410, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21027     

Iron-catalyzed cross-dehydrogenative CN coupling of thiohydantoins with various amines

A novel iron-catalyzed CN bond construction method for the hetero-cross-dehydrogenative coupling (CDC) of diverse thiohydantoins with amines utilizing TBHP as the oxidant was developed. This sp³ CH amination at the carbons alpha to carbonyl groups of thiohydantoin tolerates the presence of a wide range of functional groups and provides the corresponding N-substituted amines in moderate to good yields. Various substrate scopes and optimum reaction conditions leads inside in organic synthesis.     

A tandem and tunable Pd catalyzed C–N coupling of heteroarenols with ureas via C–OH bond activation

At this circumstance for the first time, a facile and convenient method for heteroaryl ureas has been developed via a two-step process involving in situ C–OH activation followed by palladium catalyzed C–N coupling of heteroarenols with ureas, which show excellent functional group tolerance and give out rapid coupling in good to excellent yield.     

Convenient Synthesis of Novel Quinazoline Congeners via Copper Catalyzed C–N/C–S Coupling and Their Biological Evaluation

A library of novel quinazoline scaffolds endowed with semicarbazide/oxadiazole thiol motif synthesized via an efficient and sustainable copper catalyzed C–N/C–S coupling is reported, making the presented methodology extremely valuable from economic and environmental point of view. Among the all synthesized compounds screened for in vitro antibacterial, antifungal, and anti‐TB activity, 7b , 7c , 7f , 9b , 9c , 9i , and 9j showed excellent inhibitory effect on particular strain of bacteria, fungi, and M. tuberculosis H37Rv as well. All the newly synthesized derivatives were well characterized by their IR, ¹H NMR, ¹³C NMR, mass spectroscopy as well as elemental analysis.