Comparative biological study between quinazolinyl-triazinyl semicarbazide and thiosemicarbazide hybrid derivatives.

Practical synthesis and biological activities of quinazolinyl-triazinyl semicarbazides (10a-j) and quinazolinyl-triazinyl thiosemicarbazides (11a-j) have been described. The novel semicarbazides and thiosemicarbazides were prepared by condensation of different nucleophiles like isocyanate and isothiocyanate by the displacement of chlorine atoms on the basis of functionality concept on varying conditions. The synthesized quinazolinyl-triazinyl semicarbazide and thiosemicarbazide derivatives were evaluated for their expected antimicrobial activity. All the final synthesized derivatives were characterized by their melting point, mass spectra, 1H NMR and 13C NMR as well as elemental microanalysis. The final analogues were then analyzed for their in vitro antimicrobial activity against bacteria (Gram positive and negative) and fungus using the agar streak dilution method as well as in vitro anti-HIV activity against two types of viral strains, viz. HIV type I (IIIB) and type II (ROD) by using MTT assay method. SAR and HOMO-LUMO studies were also carried out for proving the structural biological activity. Among them, compounds 10e, 10f, 11h and 11j gave best results as their energy gap is very low which makes their activity higher.

Design, synthesis, antimicrobial activity and anti-HIV activity evaluation of novel hybrid quinazoline-triazine derivatives.

A series of novel hybrid quinazoline-triazine derivatives was designed and synthesized from cyanuric chloride and anthranilic acid through sequential reactions, which contain different pharmacophores like quinazoline and substituted diaryl triazine (DATA) linked with ethylene diamine. All the newly synthesized compounds were characterized by infrared, (1)H-NMR, (13)C-NMR, MS and elemental analysis. Further, we evaluated the in vitro anti-HIV activity of the newly synthesized compounds against HIV-1 (IIIB) and HIV-2 (ROD) viral strains and as well as in vitro antimicrobial activity against four bacteria (Staphylococcus aureus, Bacillus cereus, Pseudomonas aeruginosa, Klebsiella pneumoniae) and two fungi (Aspergillus clavatus, Candida albicans) using the paper agar streak dilution method. The bioassay results indicate that four compounds namely 7d, 7n, 7r and 7s could be considered as possible potential agents.

Design, synthesis, biological evaluation, and molecular modeling of coumarin-piperazine derivatives as acetylcholinesterase inhibitors.

Acetylcholinesterase (AChE) is an important drug target for the treatment of Alzheimer's disease. A novel series of coumarin-piperazine derivatives were synthesized and their potency to inhibit human AChE enzyme (hAChE) was studied. All the final compounds were characterized by infrared, (1)H NMR, (13)C NMR, and elemental analysis. Docking experiments of the designed coumarin-piperazine derivatives were carried out in order to compare the theoretical and experimental binding affinities toward hAChE, to delineate the inhibitory mechanism. Subsequently, a structure-activity relationship (SAR) study using the molecular field method showed that the hydrophobic field and positive charge center conferred by the coumarin and piperazine moieties demonstrated an inhibitory mechanism. Among the compounds tested, 3f, 3j, and 3m were found to be the most potent inhibitors of hAChE.

Synthesis and evaluation of novel 4-substituted styryl quinazolines as potential antimicrobial agents.

In an attempt to afford possible antibacterial and anti-human immunodeficiency virus (HIV) agents, a series of 22 novel styryl quinazoline-based heterocyclic entities were designed and synthesized. Various substituted aryl urea and thiourea cores were incorporated at position 4 of quinazoline, followed by styrylation of position 2, aiming at an augmented biological potential. The synthesized compounds were well characterized through IR, (1) H NMR, (13) C NMR and elemental analyses. All compounds were screened for their in vitro anti-HIV activity against the HIV-1 (IIIB) and HIV-2 (ROD) strains. The antibacterial activity was also evaluated against various pathogenic Gram-positive and Gram-negative bacterial strains.

Privileged s-triazines: structure and pharmacological applications.

This review summarizes recent reports on s-triazine and its respective analogs from the medicinal chemistry angle. Due to its high reactivity and binding characteristic towards various enzymes, s-triazine has attracted attention. This is combined with facile synthesis and interesting pharmacology. The triazine class demonstrates wide biological applications - including antimicrobial, antituberculosis, anticancer, antiviral and antimalarial. In this article the library of s-triazine-based molecular designs has been collated with respective bioactivity. Compounds are further compared with other heterocyclic/nontriazine moieties to correlate the efficiency of privileged s-triazine. We hope this article may assist chemists in their drug design and discovery efforts.

Design, synthesis & biological evaluation of some novel quinazolinone scaffolds.

In an effort to discover new candidates with improved antimicrobial activities, we synthesized and studied invitro antimicrobial activities of various series of 3-((thiophen-2-yl)-ethyl)-2-(styryl)-quinazolin-4(3H)-one (3a-3g) and N1-(substituted aryl)-N3-[3-((3,4-dimethoxy phenyl-2-yl)-ethyl)-4(3H)-quinazolone-2-yl]-acetonyl semicarbazides (7a-7j) with an intent to overcome multiple drug resistance to the pathogenic strains and to retain psychological action to develop novel class of antibacterial agents. The structure of newly synthesized scaffolds has been affirmed on the basis of FTIR, 1H NMR, 13C NMR, mass and elemental analysis. All the final scaffolds have been subjected to in vitro antimicrobial screening against two Gram (+Ve) bacteria (S. aureus, B. subtilis), two Gram (-Ve) bacteria (E. coli, S.typhi) and two fungal strains (C. albicans, A. niger) using the broth micro-dilution method.