Martin Dolezal

• prof.
• Head of Department at Charles University in Prague

Quinazolinone derivatives have emerged as promising scaffolds in antimicrobial drug discovery. This work focuses on the design, synthesis, and evaluation of novel quinazolinone‐based compounds and predicts their potential to interact with mycobacterial penicillin‐binding proteins (PBPs). Relying on established structure–activity relationships of an...

Infectious diseases, including bacterial, fungal, and viral, have once again gained urgency in the drug development pipeline after the recent COVID‐19 pandemic. Tuberculosis (TB) is an old infectious disease for which eradication has not yet been successful. Novel agents are required to have potential activity against both drug‐sensitive and drug‐r...

The 52nd International Conference on Synthesis and Analysis of Drugs was held at the Faculty of Pharmacy, Charles University in Hradec Králové on 19 and 20 September 2024. This international event was organised by the Faculty of Pharmacy to celebrate 55 years since its foundation. It was co-organized by the Czech Pharmaceutical Society of Czech Med...

A new series of potential flutamide-like antiandrogens has been designed and synthesized to treat prostate cancer. This new series results from our research, which has been aimed at discovering new...

Abstracts from the 10th Postgraduate and Postdoc Conference of the Faculty of Pharmacy in Hradec Králové, Charles University, Hradec Králové, 22–23 January 2020.

Tuberculosis is the number one killer of infectious diseases caused by a single microbe, namely Mycobacterium tuberculosis (Mtb). The success rate of curing this infection is decreasing due to emerging antimicrobial resistance. Therefore, novel treatments are urgently needed. As an attempt to develop new antituberculars effective against both drugs...

Tuberculosis remains a serious killer among infectious diseases due to its incidence, mortality, and occurrence of resistant mycobacterial strains. The challenge to discover new antimycobacterial agents forced us to prepare a series of N-(1-hydroxy-1,3-dihydrobenzo[c][1,2]oxaborol-6-yl)(hetero)aryl-2-carboxamides 1–19 via the acylation of 6-aminobe...

Apart from the SARS-CoV-2 virus, tuberculosis remains the leading cause of death from a single infectious agent according to the World Health Organization. As part of our long-term research, we prepared a series of hybrid compounds combining pyrazinamide, a first-line antitubercular agent, and 4-aminosalicylic acid (PAS), a second-line agent. Compo...

The utility of clinically available antifungals is limited by their narrow spectrum of activity, high toxicity, and emerging resistance. Antifungal drug discovery has always been a challenging area, since fungi and their human host are eukaryotes, making it difficult to identify unique targets for antifungals. Novel antifungals in clinical developm...

Despite the established treatment regimens, tuberculosis remains an alarming threat to public health according to WHO. Novel agents are needed to overcome the increasing rate of resistance and perhaps achieve eradication. As part of our long-term research on pyrazine derived compounds, we prepared a series of their ortho fused derivatives, N-phenyl...

Sirtuin 6 (SIRT6), a member of sirtuin family (SIRT1-7), regulates a variety of cellular processes involved in aging, metabolism, and cancer. Dysregulation of SIRT6 is widely observed in different breast cancer subtypes; however, the role and function of SIRT6 in cancer development remain largely unexplored. The aim of this study was to identify no...

A series of N‐pyridinylbenzamides was designed and prepared to investigate the influence of isosterism and positional isomerism on antimycobacterial activity. Comparison to previously published isosteric N‐pyrazinylbenzamides was made as an attempt to draw structure–activity relationships in such type of compounds. In total, we prepared 44 differen...

According to the World Health Organization, tuberculosis is still in the top ten causes of death from a single infectious agent, killing more than 1.7 million people worldwide each year. The rising resistance developed by Mycobacterium tuberculosis against currently used antituberculars is an imperative to develop new compounds with potential antim...

Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis (Mtb), each year causing millions of deaths. In this article, we present the synthesis and biological evaluations of new potential antimycobacterial compounds containing a fragment of the first-line antitubercular drug pyrazinamide (PZA), coupled with methyl or ethyl esters...

We prepared a series of substituted N-(pyrazin-2-yl)benzenesulfonamides as an attempt to investigate the effect of different linkers connecting pyrazine to benzene cores on antimicrobial activity when compared to our previous compounds of amide or retro-amide linker type. Only two compounds, 4-amino-N-(pyrazin-2-yl)benzenesulfonamide (MIC = 6.25 μg...

This article represents the spectroscopic and computational studies of two new pyrazine compounds. In order to establish the structure and functional nature of the compounds, we have employed Fourier transformed infrared (FT-IR) and Raman spectra, nuclear magnetic resonance (NMR) spectra, and ultraviolet (UV) absorptions and have compared them with...

We report the design, synthesis, and in vitro antimicrobial activity of a series of N-substituted 3-aminopyrazine-2-carboxamides with free amino groups in position 3 on the pyrazine ring. Based on various substituents on the carboxamidic moiety, the series is subdivided into benzyl, alkyl, and phenyl derivatives. The three-dimensional structures of...

Background: Despite of the globally positive trends in the epidemiology of tuberculosis, the increasing rates of drug-resistant strains are urging to introduce new antituberculars into clinical practice. Development of a new chemical entity from hit to marketed drug is an extremely time and resources consuming process with uncertain outcome. Repur...

Three series of N-(pyrazin-2-yl)benzamides were designed as retro-amide analogues of previously published N-phenylpyrazine-2-carboxamides with in vitro antimycobacterial activity. The synthesized retro-amides were evaluated for in vitro growth inhibiting activity against Mycobacterium tuberculosis H37Rv (Mtb), three non-tuberculous mycobacterial st...

Hybrid compounds based on a combination of first-line antitubercular pyrazinamide (PZA) and formerly identified antimycobacterial scaffold of 4-arylthiazol-2-amine were designed. Eighteen compounds were prepared, characterized and tested for in vitro growth inhibition activity against M. tuberculosis H37Rv, M. kansasii, M. avium and M. smegmatis in...

Tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) has become a frequently deadly infection due to increasing antimicrobial resistance. This serious issue has driven efforts worldwide to discover new drugs effective against Mtb. One research area is the synthesis and evaluation of pyrazinamide derivatives as potential anti-TB drugs. In th...

Pyrazinamide, the first-line antitubercular drug, has been regarded the basic component of tuberculosis treatment for over sixty years. Researchers have investigated its effect on Mycobacterium tuberculosis for this long time, and as a result, new potential targets of pyrazinamide or its active form, pyrazinoic acid, have been found. We have design...

The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of N-[(4-(trifluoromethyl)phenyl]pyrazine-2-carboxamide have been investigated experimentally and theoretically using Gaussian09 software package. Potential energy distribution of normal modes of vibrations was done using GAR2PED program. The HOMO and...

A series of substituted N-benzyl-3-chloropyrazine-2-carboxamides were prepared as positional isomers of 5-chloro and 6-chloro derivatives, prepared previously. During the aminolysis of the acyl chloride, the simultaneous substitution of chlorine with benzylamino moiety gave rise to N-benzyl-3-(benzylamino)pyrazine-2-carboxamides as side products, i...

Aminodehalogenation of 3-chloropyrazine-2-carboxamide with variously substituted benzylamines yielded a series of fifteen 3-benzylaminopyrazine-2-carboxamides. Four compounds possessed in vitro whole cell activity against Mycobacterium tuberculosis H37Rv that was at least equivalent to that of the standard pyrazinamide. MIC values ranged from 6 to...

The FT-IR and FT-Raman spectra of N-(3-iodo-4-methylphenyl)pyrazine-2-carboxamide were recorded and the experimentally observed wavenumbers are compared with the theoretically obtained wavenumbers. The redshift of the NH stretching mode in the IR spectrum from the computed value indicated the weakening of the NH bond. The ring breathing modes of th...

Using density functional theory technique in the B3LYP approximation and cc-pVDZ (5D, 7F) basis set, the molecular structural parameters and vibrational wave numbers of two cyanopyrazine-2-carboxamide derivatives have been investigated. On the basis of potential energy distribution detailed vibrational assignments of observed FT-IR and FT-Raman ban...

Introduction: Enoyl-(acyl-carrier-protein) reductase (ENR) is a limiting step enzyme in the Fatty Acid Synthase II system. In mammals, there is no homologue to ENR, which makes it an optimal candidate target for selective anti-infective drugs. Up-to-date, only two ENR inhibitors are used in clinical practice. Area covered: This review is a surve...

The molecular structural parameters and vibrational frequencies of 5-chloro-N-(3-nitrophenyl)pyrazine-2-carboxamide have been obtained using density functional theory technique in the B3LYP approximation and CC-pVDZ (5D, 7F) basis set. Detailed vibrational assignments of observed FT-IR and FT-Raman bands have been proposed on the basis of potential...

N-Phenylpyrazine-2-carboxamides (anilides of pyrazinoic acids with simple substituents in various positions) were previously shown to possess significant biological activities in vitro, markedly anti-mycobacterial and photosynthesis-inhibiting activity. Based on structure-activity relationships (SAR) extracted from previously published series, 25 n...

Background: Silymarin, an active polyphenolic fraction of Silybum marianum, and high flavonoid content of Fagopyrum possess various interesting biological activities. The substituted pyrazine-2-carboxamides were previously used as effective elicitors of studied secondary metabolites. Objective: To study the effect of new synthetic pyrazine carbo...

Introduction: Hippocampal neurogenesis in adults is a new and attractive target for the treatment and prevention of neurodegenerative and neuro-psychiatric diseases. Recently, neurogenesis stimulating activity was observed in some of the commonly used small molecule drugs such as antidepressants and atypical antipsychotics. Stimulation of neurogen...

A series of alkylamino derivatives of N-benzylpyrazine-2-carboxamide was designed, synthesized and assayed in vitro for their antimycobacterial, antibacterial, antifungal as well as antiviral activities. Final structures were prepared from 6-chloro (1), 5-chloro (2) or 3-chloro (3) derivatives of N-benzylpyrazine-2-carboxamide by nucleophilic subst...

In this work, the vibrational spectral analysis was carried out by using FT-Raman and FT-IR spectroscopy of 5-chloro-N-(2-fluorophenyl)pyrazine-2-carboxamide. Theoretical calculations were performed by using Density Functional Theory (DFT). The complete vibrational assignments of wavenumbers were made on the basis of potential energy distribution....

A series of N-alkyl-3-(alkylamino)pyrazine-2-carboxamides and their N-alkyl-3-chloropyrazine-2-carboxamide precursors were prepared. All compounds were characterized by analytical methods and tested for antimicrobial and antiviral activity. The antimycobacterial MIC values against Mycobacterium tuberculosis H37Rv of the most effective compounds, 3-...

A set of new quaternary ammonium compounds based on pyridine-4-aldoxime was synthesized, characterized with analytical data (NMR, EA, HPLC, MS) and tested for in vitro antimicrobial activity (antibacterial, antifungal) and cytotoxicity. Quaternary pyridinium-4-aldoxime salts with length of alkyl side chain from C8 to C20 and belonging to the group...

A new approach for aminodehalogenation reaction between 3-chloropyrazine-2-carboxamide and ringsubstituted anilines is described. A series of 16 compounds (15 of them novel) derived from pyrazinamide have been synthesized successfully using the advantage of microwave-assisted reaction. The conditions for this aminodehalogenation reaction have been...

This work presents synthesis and antimicrobial evaluation of nineteen 6-alkylamino-N-phenylpyrazine-2-carboxamides. Antimycobacterial activity was determined against Mycobacterium tuberculosis H37Rv, M. kansasii and two strains of M. avium. Generally, the antimycobacterial activity increased with prolongation of simple alkyl chain and culminated in...

Pyrazine is a member of 1,4-diazines, which constitute an important class of heterocycles. Various pyrazine derivatives have been synthesized and successfully evaluated as agents with diverse pharmacological effects (including but not limited to antiproliferative, anti-infective, and effects on cardiovascular or nervous system) and some of them hav...

Benzothiazole compounds represent heterocyclic systems comprising a benzene ring fused with a thiazole ring containing nitrogen and sulphur in its structure. Besides the presence of a benzothiazole core in naturally occurring molecules, synthesized compounds containing a benzothiazole moiety in their structure proved to be a significant class of po...

Substitution of chlorine in 5-chloro-N-phenylpyrazine-2-carboxamide (1) with simple n-alkylamines yielded a series of 5-alkylamino-N-phenylpyrazine-2-carboxamides (propylamino to octylamino derivatives), which possessed similar or increased activity against M. tuberculosis H37Rv compared to parent 5-chloroderivative (1), with MIC ranging from 2.5 t...

Abstract Mycobacterial enoyl-ACP-reductase, an enzyme contributing in mycolic acids biosynthesis, has been established as promising target of novel antimycobacterial drugs. The development of inhibitors active without previous activation by catalase/peroxidase system (e.g. isoniazid), seems to be rational approach. Catalase/peroxidase system is fre...

A series of 18 N-alkyl substituted 3-aminopyrazine-2-carboxamides was prepared in this work according to previously experimentally set and proven conditions using microwave assisted synthesis methodology. This approach for the aminodehalogenation reaction was chosen due to higher yields and shorter reaction times compared to organic reactions with...

In this work a series of 15 N-benzylamine substituted 5-amino-6-methyl-pyrazine-2,3-dicarbonitriles was prepared by the aminodehalogenation reactions using microwave assisted synthesis with experimentally set and proven conditions. This approach for the aminodehalogenation reaction was chosen due to its higher yields and shorter reaction times. The...

5-Chloropyrazinamide (5-Cl-PZA) is an inhibitor of mycobacterial fatty acid synthase I with a broad spectrum of antimycobacterial activity in vitro. Some N-phenylpyrazine-2-carboxamides with different substituents on both the pyrazine and phenyl core possess significant in vitro activity against Mycobacterium tuberculosis. To test the activity of s...

A series of esters of the 3-aminopyrazine-2-carboxylic acid as potential antimycobacterial drugs was synthesized. A CEM Discover microwave reactor with an autosampler Explorer 24 which served to accelerate the reaction was used for synthesis. The prepared products were characterized by IR, 1H NMR, 13C NMR spectra, elementary analysis and melting po...

To develop new potential antimycobacterial drugs, a series of pyrazinamide derivatives was designed, synthesized and tested for their ability to inhibit the growth of selected mycobacterial strains (Mycobacterium tuberculosis H37Rv, Mycobacterium kansasii and two strains of Mycobacterium avium). This Letter is focused on binuclear pyrazinamide anal...

A series of pyrazinamide derivatives with alkylamino substitution was designed, synthesized and tested for their ability to inhibit the growth of selected mycobacterial, bacterial and fungal strains. The target structures were prepared from the corresponding 5-chloro (1) or 6-chloropyrazine-2-carboxamide (2) by nucleophilic substitution of chlorine...

A series of twelve amides was synthesized via aminolysis of substituted pyrazinecarboxylic acid chlorides with substituted benzylamines. Compounds were characterized with analytical data and assayed in vitro for their antimycobacterial, antifungal, antibacterial and photosynthesis-inhibiting activity. 5-tert-Butyl-6-chloro-N-(4-methoxybenzyl)pyrazi...

A series of 19 new compounds related to pyrazinamide were synthesized, characterized with analytical data and screened for in vitro whole cell antimycobacterial activity against Mycobacterium tuberculosis H37Rv, Mycobacterium kansasii and two types of Mycobacterium avium. The series consisted of 3-(benzylamino)-5-cyanopyrazine-2-carboxamides and 3-...

a b s t r a c t Two benzoylpyrazine ligands containing carboxyl and amide functions and their hydride-carbonyl com-plexes of ruthenium were synthesized and characterized by infrared, proton, carbon phosphorus nuclear magnetic resonance, electronic absorption and emission spectroscopy and X-ray crystallography. The experimental studies were complete...

A series of 14 new compounds related to pyrazinamide were synthesized, characterized with analytical data and screened for in vitro antimycobacterial activity against Mycobacterium tuberculosis, Mycobacterium kansasii and two types of Mycobacterium avium. The series comprised of N-substituted 3-aminopyrazine-2,5-dicarbonitriles derived from 3-chlor...

The effect of new synthetic pyrazinecarboxamide derivatives as potential elicitors of flavonolignan and flavonoid production in Silybum marianum and Ononis arvensis cultures in vitro was investigated. Both tested elicitors increased the production of flavonolignans in S. marianum callus and suspension cultures and flavonoids in O. arvensis callus a...

Design, results of in vitro antimycobacterial evaluation, and study of structure-activity relationships of various pyrazinecarboxylic acid reversible derivatives are presented. This review deals with some pyrazinamide analogues/prodrugs derived from Nphenylpyrazine- 2-carboxamides (1), arylaminopyrazine-2,5-dicarbonitriles (2), aryl/alkylsulphanylp...

Organophosphate pesticides (OPPs; e.g. chlorpyrifos, diazinon, paraoxon) are a wide and heterogeneous group of organophosphorus compounds. Their biological activity of inhibiting acetylcholinesterase (AChE) or butyrylcholinesterase (BChE) ranks them as life endangering agents. The necessary treatment after OPP exposure involves the use of parasympa...

Carbamate inhibitors (e.g. pyridostigmine bromide) are used as a pre-treatment for the prevention of organophosphorus poisoning. They work by blocking the native function of acetylcholinesterases (AChE) and thus protect AChE against irreversible inhibition by organophosphorus compounds. However, carbamate inhibitors are known for their many undesir...

Inhibitors of acetylcholinesterase are compounds widely used in the treatment of various diseases, such as Alzheimer's disease, glaucoma and Myasthenia gravis (MG). Compounds used in the therapy of MG posses a positive charge in the molecule to ensure peripheral effect of action and minimal blood-brain barrier penetration. The most prescribed carba...

A series of fifteen new compounds related to pyrazinamide (PZA) were synthesized, characterized with analytical data and screened for antimycobacterial, antifungal and antibacterial activity. The series consists of 6-chloro-5-cyanopyrazine-2-carboxamide and N-substituted 6-amino-5-cyanopyrazine-2-carboxamides, derived from the previous by nucleophi...

The treatment of organophosphorus (OP) poisoning consists of the administration of a parasympatholytic agent (e.g., atropine), an anticonvulsant (e.g., diazepam) and an acetylcholinesterase (AChE) reactivator (e.g., obidoxime). The AChE reactivator is the causal treatment of OP exposure, because it cleaves the OP moiety covalently bound to the AChE...

For Abstract see ChemInform Abstract in Full Text.

A series of sixteen pyrazinamide analogues with the -CONH- linker connecting the pyrazine and benzene rings was synthesized by the condensation of chlorides of substituted pyrazinecarboxylic acids with ring-substituted (chlorine) anilines. The prepared compounds were characterized and evaluated for their antimycobacterial and antifungal activity, a...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The effects of foliar fertilization and a growth regulator 5-tert-butyl-N-m-tolylpyrazine-2-carboxamide (MD148/II) on the growth, seed yield, and silymarin content of milk thistle (Silybum marianum Gaertn.) plants were evaluated. The study was conducted over two years at an experimental field on a slightly acid-leached cinnamonic meadow soil. The M...

Reversible inhibitors (e.g., pyridostigmine bromide, neostigmine bromide) of carbamate origin are used in the early treatment of Myasthenia gravis (MG) to block acetylcholinesterase (AChE) native function and conserve efficient amount of acetylcholine for decreasing number of nicotinic receptors. Carbamate inhibitors are known for many undesirable...

Myasthenia gravis is a rare autoimmune neuromuscular junction disorder mainly caused by antibodies being targeted against the muscle acetylcholine receptors (AChRs). The loss of AChRs leads to a defect in neuromuscular transmission resulting in muscle weakness and fatigue. Although once an often fatal illness, Myasthenia gravis can now be well mana...

Substituted pyrazinecarboxamides markedly influenced production of flavonolignans in Silybum marianum callus and suspension cultures. In this study the effect of two compounds, N-(3-iodo-4-methylphenyl)pyrazine-2-carboxamide (1) and N-(3-iodo-4-methylphenyl)-5-tert-butyl-pyrazine-2-carboxamide (2), as abiotic elicitors on flavono-lignan production...