A small library of trisubstituted pyrimidines as antimalarial and antitubercular agents

DFT, ADMET and Molecular Docking Investigations for the Antimicrobial Activity of 6,6'-Diamino-1,1',3,3'-tetramethyl-5,5'-(4-chlorobenzylidene)bis[pyrimidine-2,4(1H,3H)-dione]

Heterocyclic compounds, including pyrimidine derivatives, exhibit a broad variety of biological and pharmacological activities. In this paper, a previously synthesized novel pyrimidine molecule is proposed, and its pharmaceutical properties are investigated. Computational techniques such as the density functional theory, ADMET evaluation, and molecular docking were applied to elucidate the chemical nature, drug likeness and antibacterial function of molecule. The viewpoint of quantum chemical computations revealed that the molecule was relatively stable and has a high electrophilic nature. The contour maps of HOMO-LUMO and molecular electrostatic potential were analyzed to illustrate the charge density distributions that could be associated with the biological activity. Natural bond orbital (NBO) analysis revealed details about the interaction between donor and acceptor within the bond. Drug likeness and ADMET analysis showed that the molecule possesses the agents of safety and the effective combination therapy as pharmaceutical drug. The antimicrobial activity was investigated using molecular docking. The investigated molecule demonstrated a high affinity for binding within the active sites of antibacterial and antimalarial proteins. The high affinity of the antibacterial protein was proved by its low binding energy (-7.97 kcal/mol) and a low inhibition constant value (1.43 µM). The formation of four conventional hydrogen bonds in ligand-protein interactions confirmed the high stability of the resulting complexes. When compared to known standard drugs, the studied molecule displayed a remarkable antimalarial activity, as indicated by higher binding affinity (B.E. -5.86 kcal/mol & Ki = 50.23 M). The pre-selected molecule could be presented as a promising drug candidate for the development of novel antimicrobial agents.

Tyrosine kinase inhibition effects of novel Pyrazolo[1,5-a]pyrimidines and Pyrido[2,3-d]pyrimidines ligand: Synthesis, biological screening and molecular modeling studies

Tyrosine kinases are one of the most critical mediators in the signaling path way. Late studies have proved the part of tyrosine kinases in the pathophysiology of cancer diseases. This current research paper has focused on investigating the novel Pyrazolo[1,5-a]pyrimidines and Pyrido[2,3-d]pyrimidines as a small molecules that can inhibit tyrosine kinase in cancer cells. NCI protocol was applied to test the antitumor activity of such compounds. Leukemia and renal cancer cell lines proved to be sensitive to some derivatives such as 6b-d, 9a and 11 with GI% values ranging from 30.4 to 41.3%. In addition, compound 11 proved to be the most active against MCF-7 with GI% 62.5. The synthesized compounds were also evaluated for their inhibitory effects against EGFR kinase enzyme. Compound 9b proved to be the most active one among the synthesized series with inhibition % value of 81.72 at 25 nM concentration and IC₅₀ 8.4 nM which is very close to the reference drug Sorafenib. In vitro cytotoxicity test was also performed using the MCF-7 breast cell line. Computer modeling using the active site of tyrosine kinase as a template and the most active tyrosine kinase inhibitors were calculated. Docking studies of the synthesized compounds into the active site of EGFR kinase domain showed good agreement with the obtained biological results.

Recent advances of imidazole-containing derivatives as anti-tubercular agents

Tuberculosis still remains one of the most common, communicable, and leading deadliest diseases known to mankind throughout the world. Drug-resistance in Mycobacterium tuberculosis which threatens to worsen the global tuberculosis epidemic has caused great concern in recent years. To overcome the resistance, the development of new drugs with novel mechanisms of actions is of great importance. Imidazole-containing derivatives endow with various biological properties, and some of them demonstrated excellent anti-tubercular activity. As the most emblematic example, 4-nitroimidazole delamanid has already received approval for treatment of multidrug-resistant tuberculosis infected patients. Thus, imidazole-containing derivatives have caused great interests in discovery of new anti-tubercular agents. Numerous of imidazole-containing derivatives were synthesized and screened for their in vitro and in vivo anti-mycobacterial activities against both drug-sensitive and drug-resistant Mycobacterium tuberculosis pathogens. This review aims to outline the recent advances of imidazole-containing derivatives as anti-tubercular agents, and summarize the structure-activity relationship of these derivatives. The enriched structure-activity relationship may pave the way for the further rational development of imidazole-containing derivatives as anti-tubercular agents.

Cu-Catalyzed intermolecular [3 + 3] annulation involving oxidative activation of an unreactive C(sp3)–H bond: access to pyrimidine derivatives from amidines and ketones

An efficient approach to pyrimidines through a copper-catalyzed oxidative unreactive C(sp³)–H bond and intermolecular [3 + 3] annulation of amidines and ketones is described.

Microwave-Assisted Synthesis of Bioactive Six-Membered Heterocycles and Their Fused Analogues

This review describes the formation of six-membered heterocyclic compounds and their fused analogues under microwave activation using modern organic transformations including cyclocondensation, cycloaddition, multicomponents and other modular reactions. The review is divided according to the main heterocycle types in order of increasing complexity, starting with heterocyclic systems containing one, two and three heteroatoms and their fused analogues. Recent microwave applications are reviewed, with special focus on the chemistry of bioactive compounds. Selected examples from the 2006 to 2015 literature are discussed.

Triazine as a promising scaffold for its versatile biological behavior

Among all heterocycles, the triazine scaffold occupies a prominent position, possessing a broad range of biological activities. Triazine is found in many potent biologically active molecules with promising biological potential like anti-inflammatory, anti-mycobacterial, anti-viral, anti-cancer etc. which makes it an attractive scaffold for the design and development of new drugs. The wide spectrum of biological activity of this moiety has attracted attention in the field of medicinal chemistry. Due to these biological activities, their structure-activity relationship has generated interest among medicinal chemists and this has culminated in the discovery of several lead molecules. The outstanding development of triazine derivatives in diverse diseases within very short span of time proves its magnitude for medicinal chemistry research. Therefore, these compounds have been synthesized as target structure by many researchers, and were further evaluated for their biological activities. In this review, we have compiled and discussed the biological potential of s-triazine derivatives, which could provide a low-height flying bird's eye view of the triazine derived compounds to a medicinal chemist, for a comprehensive and target oriented information for the development of clinically viable drugs.

Synthesis of New Pyrazolo[1,5-a]pyrimidine, Triazolo[4,3-a]pyrimidine Derivatives, and Thieno[2,3-b]pyridine Derivatives from Sodium 3-(5-Methyl-1-phenyl-1H-pyrazol-4-yl)-3-oxoprop-1-en-1-olate

Condensation of sodium 3-oxo-3-(1-phenyl-1H-pyrazol-4-yl)prop-1-en-1-olate (2) with several heterocyclic amines, cyanoacetamide, cyanothioacetamide, and 2-cyanoacetohydrazide gives pyrazolo[1,5-a]pyrimidines (5a–d), pyrido[2′,3′:3,4]pyrazolo[1,5-a]pyrimidine (9), benzo[4,5]imidazo[1,2-a]pyrimidine (10), [1,2,4]triazolo[1,5-a]pyrimidine (11), and pyridine derivatives (12–14). Also, thieno[2,3-b]pyridines (15–18) were synthesized via pyridinethione (13) withα-halo ketones andα-halo ester. Structures of the newly synthesized compounds were elucidated by elemental analysis, spectral data, alternative synthetic routes, and chemical transformation whenever possible.

Recent advances in the design and synthesis of heterocycles as anti-tubercular agents

Due to the unusual structure and chemical composition of the mycobacterial cell wall, effective tuberculosis (TB) treatment is difficult, making many antibiotics ineffective and hindering the entry of drugs. With approximately 33% of infection, TB is still the second most deadly infectious disease worldwide. The reasons for this are drug-resistant TB (multidrug resistant and extensively drug resistant), persistent infection (latent TB) and synergism of TB with HIV; furthermore no new chemical entity has emerged in last 40 years. New data available from the recently sequenced genome of the mycobacterium and the application of methods of modern drug design promise much for the fight against this disease. In this review, we present an introduction to TB, followed by an overview of new heterocyclic anti-tubercular moieties published during the last decade.

4,5,8a-Triphenyl-perhydro-pyrimido[4,5-d]pyrimidine-2,7-dione monohydrate

The title compound, C₂₄H₂₂N₄O₂·H₂O, was synthesized by the trimethyl­chloro­silane-catalysed reaction between urea, benzaldehyde and acetophenone. The organic mol­ecule comprises two fused tetra­hydro­pyrimidinone rings with phenyl substituents at the 4- and 5-positions on the tetra­hydro­pyrimidinone rings and a third phenyl substituent at the ring junction 8-position. The 4- and 5-substituted phenyl rings are inclined at a dihedral angle of 22.72 (11)° to one another and make angles of 47.95 (7) and 65.76 (7)° with the third phenyl substituent. In the crystal structure, inter­molecular N—H⋯O contacts link pyrimido[4,5-d]pyrimidine mol­ecules into centrosymmetric dimers. Additional N—H⋯O and O—H⋯O hydrogen bonds involving the water mol­ecule generate a three-dimensional network.

Antituberculosis activity of the molecular libraries screening center network library

There is an urgent need for the discovery and development of new antitubercular agents that target novel biochemical pathways and treat drug-resistant forms of the disease. One approach to addressing this need is through high-throughput screening of drug-like small molecule libraries against the whole bacterium in order to identify a variety of new, active scaffolds that will stimulate additional biological research and drug discovery. Through the Molecular Libraries Screening Center Network, the NIAID Tuberculosis Antimicrobial Acquisition and Coordinating Facility tested a 215,110-compound library against Mycobacterium tuberculosis strain H37Rv. A medicinal chemistry survey of the results from the screening campaign is reported herein.

EmbR2, a structural homologue of EmbR, inhibits the Mycobacterium tuberculosis kinase/substrate pair PknH/EmbR

EmbR is a transcriptional regulator that is phosphorylated by the cognate mycobacterial STPK (serine/threonine protein kinase) PknH. Recent studies demonstrated that PknH-dependent phosphorylation of EmbR enhances its DNA-binding activity and activates the transcription of the embCAB genes encoding arabinosyltransferases, which participate in arabinan biosynthesis. In the present study, we identified a genomic region of 4425 bp, which is present in Mycobacterium tuberculosis CDC1551, but absent from M. tuberculosis H37Rv, comprising the MT3428 gene, which is homologous with embR. Homology modelling of the MT3428 gene product illustrated its close relationship (56% identity) to EmbR, and it was hence termed EmbR2. In marked contrast with EmbR, EmbR2 was not phosphorylated by PknH, although it is a substrate of other M. tuberculosis kinases, including PknE and PknF. Tryptophan fluorescence emission of EmbR2 was monitored in the presence of three different PknH-derived phosphopeptides and demonstrated that EmbR2 binds to at least two of the threonine sites known to undergo autophosphorylation in PknH. We observed that the capacity of EmbR2 to interact physically with PknH without being phosphorylated was a result of EmbR2-mediated inhibition of kinase activity: incubation of PknH with increasing concentrations of EmbR2 led to a dose-response inhibition of the autokinase activity, similarly to O6-cyclohexylmethylguanine, a known inhibitor of eukaryotic cyclin-dependent kinases. Moreover, EmbR2 inhibited PknH-dependent phosphorylation of EmbR in a dose-dependent manner. Together, these results suggest that EmbR2 is a regulator of PknH activation, thus directly participating in the control of the PknH/EmbR pair and potentially in mycobacterial physiology/virulence of M. tuberculosis CDC1551.

Synthesis of marine alkaloid: 8,9-dihydrocoscinamide B and its analogues as Novel class of antileishmanial agents

A series of marine alkaloid 8,9-dihydrocoscinamide B, its analogues and indolylglyoxylamide derivatives have been synthesized and screened for their in vitro antileishmanial activity profile in promastigote and amastigote models. Compounds 7 and 10 have shown 99-100% inhibition against promastigotes and 97-98% inhibition against amastigotes at a concentration of 10 microg/ml.

Current status and future prospects for new therapies for pulmonary tuberculosis

PURPOSE OF REVIEW

Nowadays tuberculosis is becoming a worldwide problem, and according to the World Health Organization, which declared tuberculosis a global health emergency in 1993, each year 8 million people worldwide develop the active disease and almost 3 million die.

RECENT FINDINGS

Due to this problem there is an urgent need for new strategies and drugs to fight against this disease. In this context, this review describes promising new classes of compounds against tuberculosis that are under study, as well as promising drugs that may soon be introduced onto the market. Another subject reported in this review is inhaled therapy, an important route under study for delivering antitubercular drugs directly to the lungs.

SUMMARY

The implications of new drugs and inhaled therapy in tuberculosis treatment are fewer toxic side-effects, improved pharmacokinetics properties, extensive and potent activity against Gram-positive and Gram-negative bacteria, including resistant strains, and a reduction in the total treatment time.