N-methylpiperazine Research Articles

Design, Docking, Synthesis, and In vitro Evaluation of Potent Anti-tubercular Agents Targeting DNA Gyrase

Background: Tuberculosis caused by Mycobacterium tuberculosis has been reported to infect about two-third of the global population and to continuously develop multidrug resistance. DNA gyrase, a type II topoisomerase, is a promising target of the quinolone class of drugs in the treatment of tuberculosis. Objective: The present study is focused on the design and synthesis of newer nitrogen heterocyclics containing indole, n-methyl piperazine, piperidine, and pyrrolidine ring structures. Methods: Initially designed compounds were evaluated for their affinity to the DNA gyrase target. The molecular docking performed using FlexX indicated compounds IIb5 (1-(R)-(4-hydroxyphenyl)(4- methylpiperazin-1-yl)methyl)-3-((S)-(4-hydroxyphenyl)(4-methylpiperazin-1-yl)methyl)urea and IIc5 ((1-(R)-(4-hydroxyphenyl)(4-methylpiperazin-1-yl)methyl)-3-((S)-(4-hydroxyphenyl)(4-methylpiperazin- 1-yl)methyl) thiourea to exhibit promising binding affinity (dock score of -15.01 and -13.77) respectively when compared to the reference MFX moxifloxacin (dock score -4.40) with the target 5BS8 (DNA gyrase). Further, the best 10 compounds were synthesized by one-pot synthesis employing the reaction of indole/N-methyl piperazine/piperidine/pyrrolidine with N-substituted benzaldehydes in the presence of acetamide/urea/thiourea to afford the compounds in 54.60% to 85.47% yield. The synthesized compounds were suitably characterized using chromatographic and spectroscopic tools. Results: In the microplate Alamar Blue assay (MABA), compounds IIb1, IIIc2, IIIb1, and IIb5 exhibited good minimum inhibitory concentrations of 1.6 μg/mL, 3.12 μg/mL, and 12.5 μg/mL, respectively, when compared to the standard rifampicin with 0.8 μg/mL inhibitory concentration. The MTB gyrase supercoiling assay performed using Mycobacterium tuberculosis gyrase supercoiling assay kit demonstrated compound IIb5 at a concentration of 300 μg/mL to show gyrase inhibition in comparison to MFX at 60 μg/mL. In the MTT assay performed using the human breast cancer cell line MCF-7, compounds IIc2, IIb5, and IIb1 showed IC50 values of 2.57 μM, 12.54 μM, and 12.75 μM, respectively, compared to doxorubicin (1.10 μM) at 7-48 hrs and 72 hrs of the study. Conclusion: Based on these observations, N-methyl piperazine class of compounds can serve as a lead/pharmacophore for the rational design of potent molecules against MTB gyrase to combat the growing issue of MDR-TB.

Novel Piperazine Derivatives of Vindoline as Anticancer Agents.

A series of novel vindoline-piperazine conjugates were synthesized by coupling 6 N-substituted piperazine pharmacophores at positions 10 and 17 of Vinca alkaloid monomer vindoline through different types of linkers. The in vitro antiproliferative activity of the 17 new conjugates was investigated on 60 human tumor cell lines (NCI60). Nine compounds presented significant antiproliferative effects. The most potent derivatives showed low micromolar growth inhibition (GI50) values against most of the cell lines. Among them, conjugates containing [4-(trifluoromethyl)benzyl]piperazine (23) and 1-bis(4-fluorophenyl)methyl piperazine (25) in position 17 of vindoline were outstanding. The first one was the most effective on the breast cancer MDA-MB-468 cell line (GI50 = 1.00 μM), while the second one was the most effective on the non-small cell lung cancer cell line HOP-92 (GI50 = 1.35 μM). The CellTiter-Glo Luminescent Cell Viability Assay was performed with conjugates 20, 23, and 25 on non-tumor Chinese hamster ovary (CHO) cells to determine the selectivity of the conjugates for cancer cells. These compounds exhibited promising selectivity with estimated half-maximal inhibitory concentration (IC50) values of 2.54 μM, 10.8 μM, and 6.64 μM, respectively. The obtained results may have an impact on the design of novel vindoline-based anticancer compounds.

Design, synthesis and evaluation of new methyl piperazine derivatives as anticancer agents

BackgroundTo overcome the problem of side effects and toxicity, development of new anticancer agents is needed. Recently, piperidine salicylanilide derivatives with nanomolar epidermal growth factor receptor (EGFR) inhibitory and cytotoxicity activity have been reported. In the present study effect of replacing piperidine in reported piperidine salicylanilide with N-methyl piperazine and changing substituent’s of phenyl ring at other end on anticancer activity have been explored. A series of sixteen methyl piperazine incorporated phenyl benzamide and phenyl methanone derivatives have been synthesized and tested in a panel of three cancer cell lines (adenocarcinomic human alveolar basal epithelial cells (A-549), human colon carcinoma (HCT-116) and human pancreatic carcinoma (MIAPaCa-2)), using gefitinib as standard. Further, to study the probable mechanism, due to their structural similarity with EGFR inhibitors, docking interactions with EGFR active site were observed using Schrodinger suite.ResultThe results indicated that most of the compounds showed promising activity; out of which, compound A-11 was most active having cytotoxicity much better than that of gefitinib. It showed IC50 value of 5.71 µM against A-549 cell line, 4.26 µM against HCT-116 colon cancer line and 31.36 µM against MIAPaCa-2 cell line.ConclusionIt was found that these compounds fit well in the active site and may be exhibiting anticancer activity via EGFR inhibition.Graphical

Targeting Chemoresistance in Advanced Bladder Cancers with a Novel Adjuvant Strategy.

Advanced urinary bladder cancer is characterized by rapid progression and development of therapy resistance. About 30% of the patients are diagnosed with high-grade tumors (grade > T2a). A typical nonsurgical treatment is systemic chemotherapy using cisplatin (C) and gemcitabine (G). However, treatment failure and subsequent disease progression are common in treated patients, and adjuvant therapies are not significantly effective. The therapeutic potential of a molecular hybrid of ursolic acid (UA), a pentacyclic-triterpene conjugated to N-methyl piperazine (UA4), was tested on both naïve (WT) and gemcitabine-resistant (GemR) variants of two human invasive bladder cancer cell lines, 5637 and T24. UA4 killed 5637 (4 µmol/L), T24 (4 µmol/L) WT, and GemR cells in vitro at equal potency. Pretreatment with UA4 followed by G synergistically killed WT and GemR cells by >50% compared with G followed by UA4. Oral gavage of UA4 (100 mg/kg) inhibited WT and GemR tumor growth in athymic mice. UA4 + G was more effective against GemR tumors than either drug alone. Studies revealed cytotoxic autophagy as a mechanism of UA4 cytotoxicity. UA4 induced moderate apoptosis in T24 but not in 5637 cells. Mitochondrial integrity and function were most affected by UA4 because of high levels of reactive oxygen species, disruption of mitochondrial membrane, and cell cycle arrest. These effects were enhanced in the UA4 + G combination. UA4 was well-tolerated in mice, and oral gavage led to a serum level >1 µmol/L with no systemic toxicity. These results show the potential of UA4 as a nontoxic alternative treatment for high-grade bladder cancer.

Abstract 4558: A triterpenoid derivative has strong antitumor activities in gemcitabine-resistant advanced bladder cancer models and promotes immune cell infiltration in a high grade murine syngeneic model

Abstract Bladder cancer (BC) presents a formidable challenge in treatment and patient survival, requiring particular attention to advanced stages, such as muscle-invasive stage (MIBC), due to its potential for rapid progression and substantial impact on patient morbidity and mortality. The five-year survival rate for MIBC is a meager 30%, which drops further down to 8% once tumors metastasize. Advanced bladder cancers (High grade T1) are treated with intravesical therapy with Gemcitabine and Cisplatin (G+C) combination and Stage T2 are treated neoadjuvant with G+C and cystectomy, thereby decreasing the quality of life for patients with BC. Furthermore, tumors progress beyond responding to other chemotherapy regimens such as dose-dense treatment with Methotrexate +Vinblastine + Adriamycin and Cis-platin (MVAC), all of which will further decrease the quality of life with persistent adverse toxicity. Our laboratory has developed a novel compound derived from the pentacyclic triterpenoid, Ursolic acid, termed N-methyl piperazine conjugated-Ursolic acid, or UA4, and have demonstrated its antitumor activities against both Gem-Sensitive (Gem-S) and Gem-Resistant (Gem-R) human advanced BC cell lines, T24 and 5637. We tested the combination of Gem, UA4 and Gem + UA4 in a murine non-MIBC model (MB49) to investigate the role of immune cell infiltration during tumor development and treatment response. UA4 treatment was equally effective in chemo-sensitive and chemo-resistant cell lines at dosages between 4-5µM. Previous in vitro mechanistic studies on UA4 and UA4+Gem combination treatments revealed cell death occurred through apoptosis and autophagy, along with a highly selective form of mitochondrial-mediated autophagy (mitophagy). These findings were confirmed with transmission electron microscopy ultrastructural analysis, cell cycle phase analyses, excess, changes in mitochondrial membrane potential and reactive oxygen species measurements. Gem-S and Gem-R xenografts in athymic mice further supported UA4’s efficacy in vivo, demonstrating a significant reduction in both tumor weight and volume following oral gavage (100mg/kg), with mice exhibiting no signs of systemic toxicity. Combination treatment with UA4 and Gem synergistically increased antiproliferative activity. MB49 syngeneic mice model further supported UA4 as an effective therapy, and immunofluorescence assays with immune-related markers, suggested an anti-inflammatory effect in vivo. Overall, we demonstrate UA4 has a potential to be used as an efficacious, non-toxic compound for further adjuvant use in clinical settings. Citation Format: Juliette Rose Seremak, Kunj Bihari Gupta, Siva S. Panda, Bal L. Lokeshwar. A triterpenoid derivative has strong antitumor activities in gemcitabine-resistant advanced bladder cancer models and promotes immune cell infiltration in a high grade murine syngeneic model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4558.

Salicylaldehyde-derived piperazine-functionalized hydrazone ligand-based Pt(II) complexes: inhibition of EZH2-dependent tumorigenesis in pancreatic ductal adenocarcinoma, synergism with PARP inhibitors and enhanced apoptosis.

Piperazine is an important functional unit of many clinically approved drugs, including chemotherapeutic agents. In the current study, methyl piperazine was incorporated and eight salicylaldehyde-derived piperazine-functionalized hydrazone ONN-donor ligands (L) and their Pt(II) complexes (L-PtCl) were prepared. The structures of all these ligands (L1-L8) and Pt(II) complexes (C1-C8) were determined using 1H and 13C NMR, UV-vis, FT-IR and HR-ESI MS analyses, whereas the structures of C1, C5, C6, C7 and C8 were determined in the solid state using single crystal X-ray diffraction analysis. Solution state stabilities of C3, C4, C5 and C6 were determined via time-dependent UV-vis spectroscopy. All these complexes (C1-C8) were studied for their anticancer effect in pancreatic ductal adenocarcinoma cells, including BxPC3, MIAPaCa-2 and PANC1 cells. C1-C8 displayed a potential cytotoxic effect in all these cancer cells, among which C5, C6 and C8 showed the strongest inhibitory effect in comparison with standard chemotherapeutic agents, including 5-fluorouracil (5-FU), cisplatin (CP), oxaliplatin and doxorubicin (DOX). C5, C6 and C8 suppressed the growth of pancreatic cancer cells in a dose-dependent manner. Moreover, C5, C6 and C8 inhibited clonogenic potential and invasion ability and induced apoptosis in PANC1 cells. Importantly, C5, C6 and C8 synergized the anticancer effect with PARP inhibitors, including olaparib, veliparib and niraparib, in pancreatic cancer cells, thus suggesting an important role of C5, C6 and C8 in induction of apoptosis in combination with PARP inhibitors. C5 combined with PARP inhibitors induced caspase3/7 activity and suppressed ATP production. Mechanistically, C5, C6 and C8 inhibited EZH2 protein expression to suppress EZH2-dependent tumorigenesis. Overall, these results highlighted the importance of these piperazine-functionalized Pt(II) complexes as potential anticancer agents to suppress pancreatic ductal adenocarcinoma tumorigenesis by targeting the EZH2-dependent pathway.

Synthesis, characterization, and in vitro anticancer evaluation of 2,4 disulfonylsubstituted 5-aminothiazoles

Novel 2,4-disulfonylsubstituted 5-aminothiazoles were synthesized and their anticancer activity was assessed at a high dose (10 μM) against NCI 60 cancer cell lines. Compounds 24 and 25 showed the antiproliferative activity with mean growth inhibition about 66.0%. Replacing 4-hydroxypiperidine 24 with the more hydrophilic N-methyl piperazine 25 increased the number of sensitive cell lines while replacing these hydrophilic groups with lipophilic ones abolished the anticancer activity. The COMPARE analysis showed that the tested compounds had a moderate positive correlation with alkylating agents (CCNU and methyl CCNU) and with a purine nucleotide biosynthesis inhibitor analog (L-cysteine). The results indicate that the above mechanisms of antitumor action of standard compounds are not the main ones for the tested compounds due to the lack of a high correlation. The results of this study allow us to consider compounds 24 and 25 as a basis for their further functionalization to obtain more active compounds.

Tetrahydrobenzothiophene derivatives ameliorate Mia PaCa-2 cell progression and induces apoptosis via inhibiting EGFR2 tyrosine kinase signal

A series of new thiophene analogues with acarbonitrile-basedmoiety were designed and synthesized via structural optimization. The conjugates were assessed for their in-vitro cytotoxic activity against a human pancreatic cancer cell line (Mia PaCa-2) and among them compound 5b showed IC50 value of 13.37 ± 2.37 μM. The compounds 5b (20 µM & 25 µM) and 7c (30 & 35 µM) also showed reduced clonogenicity, enhanced ROS and decreased mitochondrial membrane potential in Mia PaCa-2 cells. Treatment with these compounds also increased apoptotic population as evident with the double staining assay. Among the evaluated series, compounds 5b, 5g, 7c, and 9a attained a greater inhibitory potency than first generation’s reversible EGFR inhibitor, Gefitinib. EGFR2 enzyme inhibitory studies revealed that 5b efficiently and arbitrarily suppressed the development of EGFR2 dependent cells and inhibited the enzymatic activity with an IC50 value of 0.68 µM; interestingly, the most effective molecule 5b with N-methyl piperazine substitution, has 1.29-fold greater potency than well-known EGFR inhibitor Gefitinib and increased Gefitinib's anti-growth impact with 2.04 folds greater against Mia PaCa-2. The in-vitro studies were validated with in-silico docking studies wherein compounds 5b and 7c exhibited binding energies of −8.2 and −7.4 Kcal/mol respectively. The present study reveals that tetrahydrobenzothiophene based analogues could be a promising lead for the evolution of potent chemo preventives over pancreatic cancer.

Novel Canthin-6-one Derivatives: Design, Synthesis, and Their Antiproliferative Activities via Inducing Apoptosis, Deoxyribonucleic Acid Damage, and Ferroptosis.

A series of novel canthin-6-one (CO) derivatives (8a-l) were designed and synthesized by introducing different amide side chains at the C-2 position, and their water solubility, antiproliferative activity, and preliminary mechanism were investigated. Most compounds displayed high cytotoxicity exhibiting low-micromolar IC50 values against four human cancer cell lines, especially HT29 cells. Meanwhile, the water solubility of active CO derivatives was significantly improved. Among these compounds, compound 8h with the N-methyl piperazine group exhibiting the highest antiproliferative capability with an IC50 value of 1.0 μM against HT29 cells, which was 8.6-fold lower than that of CO. Furthermore, 8h could upregulate the levels of reactive oxygen species, leading to mitochondrial damage. In addition, 8h could promote cell apoptosis and DNA damage by regulating the expression of apoptosis-associated proteins (Bcl-2 and cleaved-caspase 3) and the DNA damage-associated protein (H2AX). Most importantly, 8h also exerted ferroptosis by reducing the GSH level and GPX4 expression as well as increasing the lipid peroxidation level. Thus, the novel CO derivative 8h with N-methylpiperazine represents a promising anticancer candidate and warrants a more intensive study.

Thermodynamics and spectroscopic properties of N-methylpiperazine with propan-1-ol, 2-propen-1-ol, 2-propyn-1-ol

ABSTRACT The density (ρ), viscosity (η), and speed of sound (u) are reported for binary mixtures of N-methylpiperazine with aliphatic primary alcohols (propan-1-ol, 2-propen-1-ol, 2-propyn-1-ol) over the entire composition range from 303.15 K to 313.15 K and at atmospheric pressure 0.1 MPa. The excess parameters (VE,κs E), deviation in viscosity, and excess partial properties (, and ) of the components at infinite dilution were calculated from the density, speed of sound, and viscosity at experimental temperatures. All the investigated systems exhibit positive values of ∆η and ∆G *E and negative values of VE and κs E over the whole composition range. The obvious deviations attribute to the association between the primary alcohols and N-methyl piperazine molecules through the hydrogen bond of O-H· · ·N. A good agreement is obtained between excess quantities and FTIR spectroscopic data.

Design, synthesis, cytotoxic activity, and in silico studies of nitrogenous stilbenes

In present study, five series of 45 nitrogenous stilbenes including 35 new compounds were designed, synthesized, and assayed for cytotoxic activities against two human tumor cell lines (K562 cells and MDA-MB-231 cells) and normal cell line (L-02 cells). Structure-activity relationships showed the introduction of N,N-dimethylamino enhanced the cytotoxicities toward K562 cells and compounds with N-methyl piperazine displayed stronger potency toward MDA-MB-231 cells. Among them, compound NS1i possessed extremely potent cytotoxicity with IC50 values 0.93 μM against K562 cells along with excellent selectivity on normal cell viability. Moreover, in silico target prediction and molecule docking demonstrated quinone reductase 2 may be the potential target for NS1i. In summary, nitrogenous stilbenes afford significant potential for the discovery of new highly efficient anticancer agents and NS1i may serve as a promising lead deserve further investigation.

Abstract 3098: Structure-based design rules for potent quadruplex-binding compounds based on the naphthalene diimide core

Abstract Quadruplex nucleic acids (G4s) are four-stranded arrangements formed by guanine-rich tracts of DNA or RNA, held together by Hoogsteen hydrogen-bonded guanine quartets. G4 sequences are widely though not randomly distributed in the human genome. They are over-represented in telomeres and in the regulatory regions of many cancer-related genes such as KIT, MYC, VEGF, RAS and HIF. G4 structures can be unwound by helicase activity but can be stabilized by the binding of high-affinity small molecules. The compound QN-302, a tetra-substituted naphthalene diimide (ND) derivative, has nanomolar affinity and selectivity for several DNA and RNA G4s over duplex DNA. QN-302 has single-digit nM anti-proliferative activity in a panel of human pancreatic cancer (PDAC) cell lines (Ahmed et al., ACS Med Chem Lett, 2020, 11, 1634-1644). It has significant anti-tumor activity in several models for PDAC - in a MIA-PACA2 xenograft, in the genetic KPC model and in an orthotopic BX-PC3 model. QN-302 is currently in an advanced stage of pre-IND development by Qualigen Inc as a novel anti-cancer agent. QN-302 is the latest in several generations of NDs developed by us and designed by computer modelling based on earlier G4 co-crystal structures determined in this laboratory. The database of seven ND-containing crystal structures includes four different NDs with distinct side chain end groups, all with intramolecular telomeric parallel G4s. End-groups include N-methyl piperazine, hydroxyl, morpholino and N-dimethyl. These structures have been systematically compared for example using least-squares overlays of the structures. All the structures have their four substituents positioned each in a G4 groove, although there are significant differences in orientations of the end groups. Surprisingly, the naphthalene diimide cores do not retain the same orientation in each structure, with three distinct orientations being apparent. Examination of ND core overlap with the adjacent G-quartet has revealed variation in the degree of heterocycle-guanine base overlap, which is dependent on the nature and size of each substituent. However, all structures show minimal ND-guanine overlap, with typically just one out of four guanines in a G-quartet being involved. This strongly implies that most of the contribution to ND-G4 affinity comes from the side chains, and especially from the protonated end groups. These and other observations have led us to develop a structure-activity framework for tetra-substituted NDs, which has culminated in their optimization and the design of QN-302, with enhanced cellular potency and G4 affinity compared to previous NDs. Citation Format: Stephen Neidle. Structure-based design rules for potent quadruplex-binding compounds based on the naphthalene diimide core [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3098.

Abstract 1678: Overcoming treatment resistance in advanced bladder cancers using a neo-adjuvant combination with a natural product analog

Abstract Urinary bladder cancer (BC) is a common cancer worldwide, with approximately 573,278 new cases and 212,536 deaths arising annually. Tumors detected beyond the transitional zone of the bladder (advanced BC) account for most deaths. In advanced BC, tumor heterogeneity and resistance to successive chemotherapy regimens are major contributors to morbidity and mortality. Toxicity associated with the combination of Gemcitabine and Cisplatin (G+C) treatment limits the efficacy of chemotherapy. We tested the potential antitumor activity of a novel combination therapy involving a semisynthetic derivative of the pentacyclic triterpene (PTA) Ursolic Acid (N-methyl piperazine conjugated Ursolate, UA4) and Gemcitabine (Gem) in two Gem resistant BC cell lines developed in the laboratory. UA4 was synthesized from the PTA Ursolic Acid and Gem was purchased from LC-Labs. We tested the response to Gem and UA4 on naïve (WT) and Gem Resistant (GemR) cells. We generated Gem resistant BC cell lines HTB-4 (T24) and HTB-9 (5637) by repeated selection in increased Gem doses in vitro. The surviving cells were tested for a stable resistant phenotype. We measured the sensitivity to Gem and UA4 alone, and in adjuvant and neo-adjuvant combinations by colorimetric, cell counting, or clonogenic assays. The antitumor efficacy of UA4 and Gem were tested in vivo by xenograft studies on Fox N1-/- athymic mice (both sexes). The expression of markers associated with drug resistance was determined by qPCR, immunoblotting, and immunofluorescence studies. The 50% growth inhibition (IC50) dose in Gem treated cells increased significantly in 5637 and T24 GemR cells - 10-fold higher in GemR (100nM) than in WT cells (10 nM). Both WT and GemR cells showed equal sensitivity to UA4 (~5 µM). GemR cells showed elevated mRNA expression of a pyrimidine salvaging enzyme, cytidine deaminase (CDA), which degrades intracellular Gem, MRP2, and ENT1, all related to limiting intracellular drug availability. Tetrahydrouridine (THU), a competitive inhibitor of CDA, reduced the resistance significantly, indicating CDA as the principal mediator of resistance in GemR cells. Oral administration of UA4 was highly effective in reducing tumor growth of 5637 WT and GemR xenografts, whereas Gem (25mg/kg, 2x per week, i.p.) did not significantly reduce growth of GemR xenografts. Gem antitumor activity on 5637 WT tumors was predominantly due to apoptosis. Increased expression of autophagy markers, but not markers of apoptosis, was evident in vitro and in vivo treatments with UA4. Overall, treatment with UA4 was equally effective in decreasing viability in both WT and GemR advanced BC cells in vitro and reducing their tumor growth in vivo. Unlike Gem, UA4 did not induce significant levels of apoptosis but mainly autophagy-induced cell death. Ongoing studies indicate potential to use UA4 as an adjuvant or neo-adjuvant therapy in the treatment of advanced BC. Citation Format: Juliette R. Seremak, Sunilkanth Bonigala, Kunj B. Gupta, Siva S. Panda, Bal L. Lokeshwar. Overcoming treatment resistance in advanced bladder cancers using a neo-adjuvant combination with a natural product analog [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1678.

Pyrazolopyrimidinone Based Selective Inhibitors of PDE5 for the Treatment of Erectile Dysfunction.

Continuing research with our earlier finding of sildenafil based analogs in the search of new inhibitors of PDE5 for erectile dysfunction suggested that there is a scope of modifications at N-methylpiperazine ring with hydrophobic region followed by hydrogen bond donor or acceptor region. However, the leads identified earlier had some limitations like poor pharmacokinetic (PK) profile, low aqueous solubility and poor bioavailability. In this direction, a new series of sildenafil based analogs were designed, synthesized and screened for their PDE5 inhibitory activity. In this series compound 18 was found to have excellent in vitro activity with selectivity towards PDE5 isozyme, also the in vivo activity and pharmacokinetic profile was excellent. The cyp inhibition and CaCO2 permeability was also excellent for compound 18.

Fluorescent "AND" logic gates for simultaneous detection of thiols and protons: photophysical properties, mechanism and bioimaging of living cells.

Five fluorescent probes TP1-5 were demonstrated as two-input "AND" molecular logic gates for the detection of thiols and protons. The molecules were designed based on "thiol receptor-spacer1-fluorophore-spacer2-proton receptor" mode. The logic gates were constructed by employing maleimide, naphthalimide and morpholine (TP1-3)/N-methyl piperazine (TP4-5) as the thiol receptor, fluorophore and proton receptor, respectively. All probes show significant fluorescence enhancements upon addition of both protons and thiols. However, much weaker spectral responses were observed with the addition of only one single analyte. The fluorescence outputs, based on photoinduced electron transfer (PET) and (twisted) intramolecular charge transfer (TICT/ICT), were modulated by the proton receptor and linker. The length of spacer1 affects the responses toward thiols, whereas spacer2 influences the sensing performance toward protons. The difference between the pKa values of morpholine (∼5.80) and N-methyl piperazine (∼7.10) enables us to detect thiols in divergent pH circumstances. TP1-3 exhibit an excellent "AND" logic function for simultaneous detection of protons and thiols as well as bioimaging thiols in weakly acidic living cells. However, TP4 and TP5 are not good candidates for executing "AND" logic operation possibly due to the stronger electron donating properties and steric effect of N-methyl piperazine.

Photodegradation of fleroxacin by g-C3N4/PPy/Ag and HPLC-MS/MS analysis of degradation pathways

To improve the photocatalytic activity of g-C3N4, graphitic phase carbon nitride was prepared using melamine as the substrate and modified with PPy and Ag nanoparticles. The structure, morphology, and optical properties of the photocatalysts were investigated using various characterization methods such as XRD, FT-IR, TEM, XPS, and UV-vis DRS. The degradation of fleroxacin, a common quinolone antibiotic, was isolated and measured using the HPLC-MS/MS technique to trace its intermediates and deduce the main degradation pathways. The results showed that g-C3N4/PPy/Ag had high photocatalytic activity and a degradation rate of more than 90%. The fleroxacin degradation reactions were primarily oxidative ring opening of the N-methyl piperazine ring structure, defluorination reactions on fluoroethyl, HCHO, and N-methyl ethylamine removal reactions.

Development of benzodioxine-heteroarylpiperazines as highly potent and selective α2c antagonists

Here is reported the design and synthesis of a series of highly potent and selective α2C antagonists using benzodioxine methyl piperazine as a central scaffold by pharmacophoric analysis to improve the pharmacokinetics of suboptimal clinical candidate molecules.

Synthesis and Antinociceptive Activity of Newly Modified Amine Analogs of Phencyclidine in Mice

Phencyclidine (PCP, I) and its substituted analogs are significant and broadly abused psychotomimetic drugs that affect the central nervous system. They possess many pharmacological properties due to the presence of specific receptors in the brain. Methyl group, despite strong electron-donating and characters of dipole moments, was placed on various positions of phenyl and amine moieties of phencyclidine along with the substitution of benzylamine, piperazine, and aniline derivatives in place of piperidine ring of phencyclidine to create novel compounds of the core with analgesic properties. For evaluation of the analgesic activities of newly synthesized compounds, they were screened by tests of tail immersion (thermal) and formalin (chemical) pains. The obtained data with the control and PCP groups were also compared. The outcomes indicated that some new compounds have more antinociceptive effects than PCP in tail immersion and formalin tests. In the tail immersion test, the methyl piperazine analog (III) shows more efficacy than others. In the formalin test, none of the compounds are as effective as phencyclidine at the earliest time-point, but compounds IV and V show effectiveness during the second stage of formalin pain. It can be concluded that the methyl-piperazine analog of phencyclidine was the best candidate to decrease acute thermal pain, and benzylamine derivatives were suitable candidates to reduce chemical pains.

Identifying highly effective coumarin-based novel cholinesterase inhibitors by in silico and in vitro studies

Inhibition of high cholinesterase levels including acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), is one of the most important strategies for the treatment of Alzheimer's disease (AD). Clinically limited drugs are used in the treatment of AD, so there is a need to find new effective inhibitors today. Therefore, in this study, synthesized six coumarin carboxamides (A1, A2, B1–B4) were evaluated against AChE and BChE by combined in silico and in vitro studies. The in vitro assessment of studied compounds revealed that A1, A2, B3, and B4 showed highest inhibition potential against AChE and BChE. As demonstrated with our structure activity relationship (SAR) study, the promising inhibition result of AChE at nanomolar concentrations was obtained with heterocyclic amines including pyrrolidine and N-methyl piperazine moieties for tertiary amide substituted coumarin compounds B3 and B4, displaying KI values of 9.78 nM and 8.07 nM, respectively. Thus, compounds B3 and B4 had around 5.7- and 6.9-fold more potency compared to the reference molecule, neostigmine. Moreover, coumarin-3-carboxamide derivative A1 bearing benzylmorpholine moiety on coumarin scaffold at position 3 displayed stronger inhibition potential against BChE. Furthermore, in order to better understand their molecular mechanisms in these targets, we conducted molecular docking and MD simulations. Our promising preclinical results show that the lead compounds A1, A2, B3 and B4 have high potential as effective inhibitors for the treatment of AD.

Experimental and theoretical study on the synthesis and thermophysical properties of newer tricationic ionic liquids

The synthesis of nineteen new linear symmetric tricationic ionic liquids (7a-s) with imidazolium-based structures is reported. The physicochemical properties of the new cations as morpholine, N,N-dimethyl amino pyridine, N-methylimidazole, N-methyl piperazine, also the anions as Cl−, −OSO2CH3, −OSO2Ph, CH3CO2−, CF3CO2− were evaluated. The theoretical studies employing DFT and MD simulation were used to analyze the experimental data as density, molar volume, solubility, lattice energy and ΔH. The strategy of synthesis provided the imidazolium core with different nucleophiles in good yield and diversity. The results of the density and molar volume were compared with the experimental data verifying a close agreement. The values of relative solubility and solubility parameters showed that these molecules are completely insoluble in non-polar solvents, and their affinity predominates in solvents with high dipole moments such as water, alcohols, and ketones. The lattice energy values showed a tendency towards the formation of stable ionic liquids.