Synthesis and antimicrobial activity of Schiff bases and 2-azetidinones derived from quinazolin-4(3H)-one

Molecular Docking and Biophysical Studies for Antiproliferative Assessment of Synthetic Pyrazolo-Pyrimidinones Tethered with Hydrazide-Hydrazones

Chemotherapy represents the most applied approach to cancer treatment. Owing to the frequent onset of chemoresistance and tumor relapses, there is an urgent need to discover novel and more effective anticancer drugs. In the search for therapeutic alternatives to treat the cancer disease, a series of hybrid pyrazolo[3,4-d]pyrimidin-4(5H)-ones tethered with hydrazide-hydrazones, 5a-h, was synthesized from condensation reaction of pyrazolopyrimidinone-hydrazide 4 with a series of arylaldehydes in ethanol, in acid catalysis. In vitro assessment of antiproliferative effects against MCF-7 breast cancer cells, unveiled that 5a, 5e, 5g, and 5h were the most effective compounds of the series and exerted their cytotoxic activity through apoptosis induction and G0/G1 phase cell-cycle arrest. To explore their mechanism at a molecular level, 5a, 5e, 5g, and 5h were evaluated for their binding interactions with two well-known anticancer targets, namely the epidermal growth factor receptor (EGFR) and the G-quadruplex DNA structures. Molecular docking simulations highlighted high binding affinity of 5a, 5e, 5g, and 5h towards EGFR. Circular dichroism (CD) experiments suggested 5a as a stabilizer agent of the G-quadruplex from the Kirsten ras (KRAS) oncogene promoter. In the light of these findings, we propose the pyrazolo-pyrimidinone scaffold bearing a hydrazide-hydrazone moiety as a lead skeleton for designing novel anticancer compounds.

Evaluation and Docking Study of Pyrazine Containing 1, 3, 4-Oxadiazoles Clubbed with Substituted Azetidin-2-one: A New Class of Potential Antimicrobial and Antitubercular

BACKGROUND

Tuberculosis (TB) caused by Mycobacterium tuberculosis is one of the main killers of people all over the world. The major hurdles with existing therapy are the lengthy regimen and appearance of multi drug resistant (MDR) and extensively drug resistant (XDR) strains of M.tuberculosis.

AIMS

The present work was aimed to synthesize and determine antitubercular and antimicrobial potential of some novel 3-chloro-4-aryl-1-[4-(5-pyrazin-2-yl[1,3,4]oxadiazole-2-ylmethoxy)-phenyl]-azetidin-2-one derivatives 7: (A: -H: ) from pyrazinoic acid as precursor, which is a well-established antitubercular agent. Here we report the synthesis of a new class of heterocyclic molecules in which pyrazine, 1, 3, 4-oxadiazole and azetidinone moieties were present in one frame work.

METHODS

Pyrazinoic acid (1: ) was esterified first (2: ) followed by amination to produce hydrazide (3: ) which was refluxed with POCl3 to obtain 2-chloromethyl-5pyrazino-1, 3, 4-oxadiazole (4: ). This was then further reacted with 4-amino phenol to obtain 4-[5-pyrazino-1, 3, 4-oxadiazol-2-yl-methoxy]-phenyl amine (5: ) which on condensation with various aromatic aldehydes afforded a series Schiff's bases 6(A-H): . Dehydrative annulations of 6(A-H): in the presence of chloroacetyl chloride and triethylamine yielded 3-chloro-4-aryl-1-[4-(5-pyrazin-2-yl-[1, 3, 4]oxadiazole-2-ylmethoxy)-phenyl]-azetidin-2-one derivatives 7(A-H): . Antibacterial, antifungal and antitubercular potential of all the synthesized compounds were assessed. Docking study was performed using the software VLife Engine tools of Vlifemds 4.6 on the protein lumazine synthase of M. tuberculosis (PDB entry code 2C92).

RESULTS

The present studies demonstrated that synthesized oxadiazole derivatives have good antimicrobial activity against the various microorganisms. Among the synthesized derivative, 7B: and 7G: were found to be prominent compounds which have potential antibacterial, antifungal and antitubercular activity (with MIC 3.12 µg/ml and high dock score ranging from -59.0 to -54.0) against Mycobacterium tuberculosis.

CONCLUSIONS

Derivatives 7B: and 7G: would be effective lead candidates for tuberculosis therapy.

Aryl Quinazolinone Derivatives as Novel Therapeutic Agents against Brain-Eating Amoebae

Naegleria fowleri and Balamuthia mandrillaris are protist pathogens that infect the central nervous system, causing primary amoebic meningoencephalitis and granulomatous amoebic encephalitis with mortality rates of over 95%. Quinazolinones and their derivatives possess a wide spectrum of biological properties, but their antiamoebic effects against brain-eating amoebae have never been tested before. In this study, we synthesized a variety of 34 novel arylquinazolinones derivatives (Q1-Q34) by altering both quinazolinone core and aryl substituents. To study the antiamoebic activity of these synthetic arylquinazolinones, amoebicidal and amoebistatic assays were performed against N. fowleri and B. mandrillaris. Moreover, amoebae-mediated host cells cytotopathogenicity and cytotoxicity assays were performed against human keratinocytes cells in vitro. The results revealed that selected arylquinazolinones derivatives decreased the viability of B. mandrillaris and N. fowleri significantly (P < 0.05) and reduced cytopathogenicity of both parasites. Furthermore, these compounds were also found to be least cytotoxic against HaCat cells. Considering that nanoparticle-based materials possess potent in vitro activity against brain-eating amoebae, we conjugated quinazolinones derivatives with silver nanoparticles and showed that activities of the drugs were enhanced successfully after conjugation. The current study suggests that quinazolinones alone as well as conjugated with silver nanoparticles may serve as potent therapeutics against brain-eating amoebae.

Monocyclic β-Lactam: A Review on Synthesis and Potential Biological Activities of a Multitarget Core

A monocyclic ring in their structure characterizes monobactams, a subclass of β-lactam antibiotics. Many of these compounds have a bactericidal mechanism of action and acts as penicillin and cephalosporins, interfering with bacterial cell wall biosynthesis. The synthesis of novel β-lactams is an emerging area of organic synthesis research due to the problem of increasing bacterial resistance to existing β -lactam antibiotics, and, in this way, new compounds have been presented with several structural modifications, aiming to improve biological activities. Among the biological activities studied, the most outstanding are antibacterial, antitubercular, anticholesterolemic, anticancer, antiinflammatory, antiviral, and anti-enzymatic, among others. This review explores the vast number of works related to monocyclic β-lactams, compounds of great importance in scientific research.

Experimental and molecular topology-based biological implications of Schiff base complexes: a concise review

This review is a gentle introduction toward Schiff bases with special attention to bioinorganic aspects. Depending on the nature of condensation moieties (ketonic or aldehydic) with primary amine, a large number of novel compounds are reported every year with applicability in various material science aspects. Herein, a burgeoning literature overview is presented to provide a salient discussion of the current status of these molecular systems. Schiff bases are designed depending on the particular desirable properties. For instance, to enlighten a biologically relevant molecule, it is always appreciated when a prepared compound shows biological membrane crossing and nucleic acid linking potential. Under such purview, the Schiff base functional group can serve as an enhancer of biomembrane traversing capability. In addition to various other catalytic aspects, the type of disease to be encountered also matters. Nowadays, theoretical chemistry is applied before synthesizing a compound of this sort and fruitful results are first depicted and, if found feasible, a suitable synthetic route is followed to synthesize Schiff base compounds. Molecular charge topology analysis under theoretical expression is analyzed generally to predict the biological relevance of a molecule.

4(3H)-Quinazolinone derivatives: Promising antibacterial drug leads

Emergence of drug resistance has created unmet medical need for the development of new classes of antibiotics. Discovery of new antibacterial agents with new mode of action remains a high priority universally. 4(3H)-quinazolinone, a fused nitrogen heterocyclic compound has emerged as a biologically privileged structure, possessing a wide range of biological properties viz. anticancer, antibacterial, antitubercular, antifungal, anti-HIV, anticonvulsant, anti-inflammatory and analgesic activities. Promising antibacterial properties of quinazolinones have enthused the medicinal chemists to explore and develop this fused heterocyclic system for new antibacterial agents. Utilization of quinazolinone core for the design and synthesis of new antibacterial agents has recently gained momentum. This review aims to provide an overview of the structures and antibacterial activity of various 4(3H)-quinazolinone derivatives covering various aspects of in vitro and in vivo pharmacological activities and structure activity relationships (SARs).

Synthesis, Antimicrobial and Anti-inflammatory Activity of Some New Benzoxazinone and Quinazolinone Candidates

Benzoxazinones and quinazolinones have a wide spectrum of biological activity. In this paper we focused on studying the antimicrobial and anti-inflammatory activities of some newly synthesized benzoxazinone and quinazolinone derivatives. Thus we prepared 2-[α-benzoylaminostyryl]-6,8-dibromo-3,1-benzoxazin-4(H)-one 2 which underwent a reaction with primary and secondary amines, and hydrazine hydrate to give compounds 3, 4 and 5, respectively. Treatment of 2 with hydroxylamine hydrochloride, formamide and/or NaN3/AcOH afforded compounds 7, 8, 11 and 12, respectively. Also, compound 2 reacted with maleic anhydride, aromatic hydrocarbons and/or active methylene compounds to produce compounds 13, 15a-c and 16, respectively. Most of the newly synthesized compounds showed significant antimicrobial and anti-inflammatory activities comparable to ampicillin, mycostatine and indomethacin positive controls.

Permethyl Cobaltocenium (Cp*2Co+) as an Ultra-Stable Cation for Polymer Hydroxide-Exchange Membranes

Hydroxide (OH(-))-exchange membranes (HEMs) are important polymer electrolytes enabling the use of affordable and earth-abundant electrocatalysts for electrochemical energy-conversion devices such as HEM fuel cells, HEM electrolyzers, and HEM solar hydrogen generators. Many HEM cations exist, featuring desirable properties, but new cations are still needed to increase chemical stability at elevated temperatures. Here we introduce the permethyl cobaltocenium [(C5Me5)2Co(III)(+) or Cp(*)2Co(+)] as an ultra-stable organic cation for polymer HEMs. Compared with the parent cobaltocenium [(C5H5)2Co(III)(+) or Cp2Co(+)], Cp(*)2Co(+) has substantially higher stability and basicity. With polysulfone as an example, we demonstrated the feasibility of covalently linking Cp(*)2Co(+) cation to polymer backbone and prepared Cp(*)2Co(+)-functionalized membranes as well. The new cation may be useful in designing more durable HEM electrochemical devices.

Chemical characteristics, synthetic methods, and biological potential of quinazoline and quinazolinone derivatives

The heterocyclic fused rings quinazoline and quinazolinone have drawn a huge consideration owing to their expanded applications in the field of pharmaceutical chemistry. Quinazoline and quinazolinone are reported for their diversified biological activities and compounds with different substitutions bring together to knowledge of a target with understanding of the molecule types that might interact with the target receptors. Quinazolines and quinazolinones are considered as an important chemical for the synthesis of various physiological significance and pharmacological utilized molecules. Quinazolines and quinazolinone are a large class of biologically active compounds that exhibited broad spectrum of biological activities such as anti-HIV, anticancer, antifungal, antibacterial, antimutagenic, anticoccidial, anticonvulsant, anti-inflammatory, antidepressant, antimalarial, antioxidant, antileukemic, and antileishmanial activities and other activities. Being considered as advantaged scaffold, the alteration is made with different substituent.

Design, synthesis, and antibacterial activity of novel Schiff base derivatives of quinazolin-4(3H)-one

Novel imine derivatives of quinazolin-4(3H)-one were designed and synthesized by using aminoethyl moieties to increase the amine bridge of quinazolin-4(3H)-one amine and then introducing various aromatic aldehydes. The target compounds were characterized by proton nuclear magnetic resonance spectroscopy ((1)H NMR), carbon nuclear magnetic resonance spectroscopy ((13)C NMR), mass spectrometry (MS), infrared spectroscopy (IR), elemental analysis, and X-ray diffraction crystallography. Bioassay results indicated that some of the compounds showed good to excellent antibacterial activities against tobacco bacterial wilt and tomato bacterial wilt. The 50% effective concentrations (EC50) of the compounds against tobacco and tomato bacterial wilts ranged from 63.73 μg/mL to 201.52 μg/mL and 38.64 μg/mL to 81.39 μg/mL, respectively, which are lower than that the positive control thiodiazole copper (216.70 and 99.80 μg/mL). These results indicated that novel Schiff base derivatives containing the 4(3H)-quinazolinone moiety can effectively control tobacco and tomato bacterial wilts.

The chemistry and biological potential of azetidin-2-ones

Azetidin-2-ones, commonly referred as β-lactams, represent a unique ring system, with interesting chemistry and great biological potential. Besides its well known antibiotic activity, this ring system exhibits a wide range of activities, attracting the attention of researchers. The biological and pharmacological profile of azetidin-2-ones is reviewed here comprehensively with several examples under fourteen different activity heads. The chemistry and methods of synthesis have also been discussed.

Schiff Bases: A Versatile Pharmacophore

Schiff bases are condensation products of primary amines with carbonyl compounds gaining importance day by day in present scenario. Schiff bases are the compounds carrying imine or azomethine (–C=N–) functional group and are found to be a versatile pharmacophore for design and development of various bioactive lead compounds. Schiff bases exhibit useful biological activities such anti-inflammatory, analgesic, antimicrobial, anticonvulsant, antitubercular, anticancer, antioxidant, anthelmintic, antiglycation, and antidepressant activities. Schiff bases are also used as catalysts, pigments and dyes, intermediates in organic synthesis, polymer stabilizers, and corrosion inhibitors. The present review summarizes information on the diverse biological activities and also highlights the recently synthesized numerous Schiff bases as potential bioactive core.

Synthesis, Characterization, and Anti-Inflammatory Activity of Newer Quinazolinone Analogs

A series of 3-[2′-(Substitutedbenzylideneamino)phenyl]-2-methyl-6-substituted quinazolin-4-ones (5–10), 3-[2′-(3^″-chloro-2^″-oxo-4^″-substitutedphenylazetidin-1^″-yl)phenyl]-2-methyl-6-substitutedquinazolin-4-ones (11–16), and 3-[2′-(2^″-substitutedphenyl-4^″-oxo-1^″,3^″-thiazolidin-3^″-yl)phentl]-2-methyl-6-substitutedquinazolin-4-ones (17–22) have been synthesized in the present study. The structures of the synthesized compounds were assigned on the basis of elemental analysis, IR, ¹H NMR, and mass spectral data. All the newly synthesized compounds were screened for anti-inflammatory and analgesic activities.