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In this study, a novel quinazolinone analogue was designed and synthesized by substituting the thiourea group and phenyl ring at N-3 and C-2 positions of the quinazoline ring, respectively. The prepared analogue was tested for its antibacterial, antitubercular and anti-HIV potencies. The agar dilution method was used to test the antibacterial potency of entire prepared derivatives against various gram-positive and gram-negative microorganism strains. Compound 1-(3-chlorophenyl)-2-methyl-3-(4-oxo-2-methylquinazolin-3(4H)-yl)isothioureas (Xi) shown most potent activity against Klebsiella pneumoniae, Proteus vulgaris, and Staphylococcus epidermidis at 1.6 µg/mL. The compound (Xi) exhibited the antitubercular activity at the minimum microgram of 6.25 µg/mL and anti-HIV activity at 1.17 µg/mL against HIV1 and HIV2. The compound (Xi) offers a potential lead for further optimization and development to new antitubercular and anti-HIV agents. The results obtained from this study confirm that the synthesized and biologically evaluated quinazolines showed promising antimicrobial, antitubercular, and anti-HIV activities and new scaffolds for antimicrobial activity. [ABSTRACT FROM AUTHOR]

In this study, a new benzopyrimidine analog was designed and synthesized by substituting 3-nitrophenyl ring and thiosemicarbazide nucleus at N-3 and C-2 positions of quinazoline ring, respectively. The title compounds, 1-substituted-3-(3-(2-chlorophenyl)-4-oxo-3,4-dihydrobenzopyrimidin-2-ylamino)isothioureas 7A – 7J were obtained via reactions of 2-hydrazino-3-(2-chlorophenyl)quinazolin-4(3H)-one (5) with different alkyl/aryl isothiocyanates followed by methylation with dimethyl sulphate. All synthesized compounds were screened for their antitubercular, anti-HIV, and antibacterial activity against selected Gram-positive and Gram-negative bacteria using agar diffusion method. Amongst, compounds 2-methyl-3-(3-(2-chlorophenyl)-4-oxo-3,4-dihydrobenzopyrimidin-2-ylamino)-1-(3-chloropheny)isothiourea (7I) and 2-methyl-3-(3-(2-chlorophenyl)-4-oxo-3,4-dihydrobenzopyrimidin-2-ylamino)-1-(3-chlorophenyl)isothiourea (7F) showed the most potent activity against P. vulgaris and S. aureus with a MIC of 3 μg/mL. Compound 7I exhibited antitubercular activity at a minimum MIC of 3.125 μg/mL and anti-HIV activity at EC50 of 2.91 μg/mL against HIV1 and HIV2, thus offering probable lead for further development and optimization of new antitubercular and anti-HIV drugs. Results obtained in this study confirm that the synthesized and biologically evaluated benzopyrimidines possess promising antimicrobial, antitubercular, and anti-HIV properties and provide new scaffolds for antimicrobial activity. [ABSTRACT FROM AUTHOR]

A series of 1-(3-benzyl-4-oxo-3H-quinazolin-2-yl)-4-(substituted) thiosemicarbazides (AS1-AS10) were obtained by the reaction of 2-hydrazino- 3-benzyl quinazolin-4(3H)-one (6) with different dithiocarbamic acid methyl ester derivatives. The key intermediate 3-benzyl-2-thioxo-2,3-dihydro-1Hquinazolin-4-one (4) was obtained by reacting benzyl amine (1) with carbon disulphide and sodium hydroxide in dimethyl sulphoxide to give sodium dithiocarbamate, which was methylated with dimethyl sulfate to yield the dithiocarbamic acid methyl ester (2) and condensed with methyl anthranilate (3) in ethanol yielded the desired compound (4) via the thiourea intermediate. The SH group of compound (4) was methylated for the favorable nucleophilic displacement reaction with hydrazine hydrate, which afford 2-hydrazino-3- benzyl-3H-quinazolin-4-one (6). The IR, 1H, and 13C NMR spectrum of these compounds showed the presence of peaks due to thiosemicarbazides, carbonyl (C=O), NH and aryl groups. The quinazolin-4-one moiety molecular ion peaks (m/z 144) were observed all the mass spectrum of compounds (AS1-AS10). Elemental (C, H, N) analysis satisfactorily confirmed purity of the synthesized compounds and elemental composition. All synthesized compounds were also screened for their antimicrobial activity against selective gram positive and gram negative by agar dilution method. In the present study compounds AS8 and AS9 were emerged as the most active compounds of the series.

The substituted thiosemicarbazide moiety was placed at the C-2 position and 2-methylphenyl group at N-3 position of quinazoline ring and obtained compounds were tested for their antitubercular activities and antibacterial activities against selected gram-positive and gram-negative bacteria. The target compounds 1-(3-(2-methylphenyl)-4-oxo-3H-quinazolin-2-yl)-4-(substituted) thiosemicarbazides were obtained by the reaction of 2-hydrazino-3-(2-methylphenyl) quinazolin-4(3 H)-one with different dithiocarbamic acid methyl ester derivatives. All synthesized compounds were also screened for their antimicrobial activity against selective gram-positive and gram-negative bacteria by agar dilution method. Among the series, 1-[3-(2-methylphenyl)-4-oxo-3 H-quinazolin-2-yl]-4-[4-chlorophenyl]-thiosemicarbazide exhibited the most potent activity against S. typhi, E. coli, and B. subtilis, while 1-[3-(2-methylphenyl)-4-oxo-3 H-quinazolin-2-yl]-4-[4-nitrophenyl]-thiosemicarbazide was the most potent against E. coli, B. subtilis, P. aeruginosa, S. typhi, and S. flexneri. These two compounds exhibited the antitubercular activity at the minimum concentration (3 μg/mL) that offered potential for further optimization and development of new antitubercular agents. The obtained results demonstrated promising antimicrobial and antitubercular activities of the synthesized quinazoline compounds which could be used as new scaffolds for improving their antimicrobial activity. [ABSTRACT FROM AUTHOR]

In recent years, fluorescent probes for the detection of environmentally and biologically important metal cations have received extensive attention for designing and development of fluorescent chemosensors. Herein, we report the photophysical results of 2-(2-fluorobenzoyl)- N-(2-methoxyphenyl) hydrazinecarbothioamide (4) functionalized as Ni (II) sensor in micromolar concentration level. Through fluorescence titration at 488 nm, we were confirmed that ligand 4 showed the remarkable emission by complexation between 4 and Ni (II) while it appeared no emission in case of the competitive ions (Cr, Fe, Co, Ba, Cu, Ca, Na, K, Cu, Cs). Furthermore, ligand 4 exhibited no toxicity with precise cell permeability toward normal living cells using L929 cell lines in bio imaging experiment investigated through confocal fluorescence microscope. The non-toxic behavior of ligand 4 (assessed by MTT assay) and its ability to track the Ni in living cells suggest its possibility to use in biological system as nickel sensor. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A series of novel 12α-alkoxycarbonyl thiosemicarbazide molecular tweezers based on 3α-(1-naphthoyl) deoxycholic acid methyl ester were synthesised under microwave irradiation. Their structures were characterised by 1H NMR, IR, MS spectra and elemental analysis. Their chiral recognition properties for the methyl esters of amino acids were investigated. The preliminary results showed that these molecular tweezers have good enantioselective recognition for D/L-amino acid methyl esters. [ABSTRACT FROM AUTHOR]

Background: Although exhaustive efforts to prevent and treat tuberculosis (TB) have been made, the problem still continues due to multi-drug-resistant (MDR) and extensively drugresistant TB (XDR-TB). It clearly highlights the urgent need to develop novel "druggable" molecules for the co-infection treatment and strains of MDR-TB and XDR-TB., Objective: In this approach, a hybrid molecule was created by merging two or more pharmacophores. The active site of targets may be addressed by each of the pharmacophores and proffers the opportunity for selectivity. In addition, it also reduces undesirable side effects and drug-resistance., Methods: In this study, a novel quinazolinone analog was designed and synthesized by substituting thiourea nucleus and phenyl ring at N-3 and C-2 position of quinazoline ring, respectively. All title compounds were tested for antitubercular activity by in vitro M. tuberculosis and anti-human immunodeficiency virus (HIV) activity by MT-4 cell assay method. The agar dilution method was used to test the antibacterial potency of entire prepared derivatives against various strains of grampositive and gram-negative microorganisms., Results: The title compounds, 1-(substituted)-2-methyl-3-(4-oxo-2-phenyl quinazolin-3(4H)-yl) isothioureas (QTS1 - QTS15) were synthesized by the reaction between key intermediate 3-amino- 2-phenylquinazolin-4(3H)-one with various alkyl/aryl isothiocyanates followed by methylation with dimethyl sulphate. Among the series, compound 1-(3-chlorophenyl)-2-methyl-3-(4-oxo-2-phenyl quinazolin- 3(4H)-yl) isothioureas (QTS14) showed the highest potency against B. subtilis, K. pneumonia and S. aureus at 1.6 μg/mL. The compound QTS14 exhibited the most potent antitubercular activity at the MIC of 0.78 μg/mL and anti-HIV activity at 0.97 μg/mL against HIV1 and HIV2., Conclusion: The results obtained from this study confirm that the synthesized and biologically evaluated quinazolines showed promising antimicrobial, antitubercular and anti-HIV activities. The new scaffolds proffer a plausible lead for further development and optimization of novel antitubercular and anti-HIV drugs., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)