Compounds 5r Research Articles

Design, synthesis and anti-HIV evaluation of 5-alkyl- 6-(benzo[d][1,3]dioxol-5-alkyl)-2-mercaptopyrimidin-4(3H)-ones as potent HIV-1 NNRTIs

In order to discover and develop the new HIV-1 NNRTIs, a series of 5-alkyl-6-(benzo[d][1,3]dioxol-5-ylalkyl)-2-mercaptopyrimidin-4(3H)-ones was synthesized and screened for their in vitro cytotoxicity against HIV-1. Most of the compounds we synthetized showed high activity against wild-type HIV-1 strain (IIIB) while IC50 values are in the range of 0.06–12.95 μM. Among them, the most active HIV-1 inhibitor was compound 6-(benzo[d][1,3]dioxol-5-ylmethyl)-5-ethyl-2-((2-(4-hydroxyphenyl)-2-oxoethyl)thio)pyrimidin-4(3H)-one (5b), which exhibited similar HIV-1 inhibitory potency (IC50 = 0.06 μM, CC50 = 96.23 μM) compared with nevirapine (IC50 = 0.04 μM, CC50 >200 μM) and most of compounds exhibited submicromolar IC50 values indicating they were specific RT inhibitors. The compounds 5b, 6-(benzo[d] [1,3]dioxol-5-yl)-5-ethyl-2-((2-(4-hydroxyphenyl)-2-oxoethyl)thio)pyrimidin-4(3H)-one (5c) and 4-(2-((4-(benzo[d][1,3]dioxol-5-ylmethyl)-5-ethyl-6-oxo-1,6-dihydropyrimidin-2-yl)thio)acetyl)phenylbenzo[d][1,3]dioxole-5-carboxylate (5r) were selected for further study. It was found that all of them had little toxicity to peripheral blood mononuclear cell (PBMC), and had a good inhibitory effect on the replication of HIV-1 protease inhibitor resistant strains, fusion inhibitor resistant strains and nucleosides reverse transcriptase inhibitor resistant strains, as well as on clinical isolates. Besides, compound 5b and 5c showed inhibition of HIV-1 RT RNA-dependent DNA polymerization activity and DNA-dependent DNA polymerization activity, while compound 5r only showed inhibition of HIV DNA-dependent DNA polymerization activity, which was different from classical reverse transcriptase inhibitors. Our study which offered the preliminary structure-activity relationships and modeling studies of these new compounds has provided the valuable avenues for future molecular optimization.

Pharmacological Inhibition of Cathepsin S Suppresses Abdominal Aortic Aneurysm in Mice

Evidence suggests that cathepsin S (CTSS), a potent mammalian elastase, participates in abdominal aortic aneurysm (AAA) formation. This study examines the hypothesis that pharmacological inhibition of CTSS with an α-ketoamide based compound 6r might suppress AAA in mice.

Discovery of N-substituted-3-phenyl-1,6-naphthyridinone derivatives bearing quinoline moiety as selective type II c-Met kinase inhibitors against VEGFR-2

New N-substituted-3-phenyl-1,6-naphthyridinone derivatives are designed and synthesized, based on structural modification of our previously reported compound 3. Extensive enzyme-based SAR studies and PK evaluation led to the discovery of compound 4r, with comparable c-Met potency to that of Cabozantinib and high VEGFR-2 selectivity, while Cabozantinib displayed no VEGFR-2 selectivity. More importantly, at oral doses of 45 mg/kg (Q.D.), compound 4r exhibits significant tumor growth inhibition (93%) in a U-87MG human gliobastoma xenograft model. The promising selectivity against VEGFR-2 and excellent tumor growth inhibition of compound 4r suggest that it could be used as a new lead molecule for further discovery of selective type II c-Met inhibitors.

Synthesis and antitumor evaluation of (aryl)methyl-amine derivatives of dehydroabietic acid-based B ring-fused-thiazole as potential PI3K/AKT/mTOR signaling pathway inhibitors.

In an attempt to search for new natural product-based antitumor agents, a series of novel (aryl)methyl-amine derivatives of dehydroabietic acid-based B ring-fused-thiazole were designed and synthesized. The primary bioassay showed that compounds 5r and 5s presented certain inhibitory activity against cancer cells, weak cytotoxic activity against normal cells, and inhibitory activity against PI3K/AKT/mTOR signaling pathway. The binding modes and the binding site interactions between the active compounds and the target proteins were predicted preliminarily by the molecular docking method.

Design, synthesis and insecticidal activity of novel semicarbazones and thiosemicarbazones derived from chalcone

Thirty semicarbazone and thiosemicarbazone derivatives (2a–w and 4a–g) from chalcones containing furan and thiophene ring were designed and synthesized. They were characterized by IR, 1H NMR, 13C NMR and HRMS. The crystal structure of compound 2r was characterized by single crystal X-ray diffraction. It crystallizes in the monoclinic system with space group P21/c. The insecticidal activity of the synthesized compounds was screened against Leucania separata and Pieris rapae using beta-cypermethrin as the comparative standard. The results displayed that most of them had remarkable insecticidal activity. Among them, compounds 2e–g showed better activity than beta-cypermethrin against L. separata and P. rapae. Compound 2p also possessed a better activity than beta-cypermethrin against P. rapae. The insecticidal activities of these compounds have been reported for the first time.

Synthesis, cytotoxic assessment, and molecular docking studies of 2,6-diaryl-substituted pyridine and 3,4- dihydropyrimidine-2(1H)-one scaffolds.

Cancer is one of the main global health problems. In order to develop novel antitumor agents, we synthesized 3,4-dihydropyrimidine-2(1H)-one (DHPM) and 2,6-diaryl-substituted pyridine derivatives as potential antitumor structures and evaluated their cytotoxic effects against several cancer cell lines. An easy and convenient method is reported for the synthesis of these derivatives, employing cobalt ferrite (CoFe 2 O 4 @SiO 2 -SO 3 H) magnetic nanoparticles under microwave irradiation and solvent-free conditions. The structural characteristics of the prepared nanocatalyst were investigated by FTIR, XRD, SEM, and TGA techniques. In vitro cytotoxic effects of the synthesized products were assessed against the human breast adenocarcinoma cell line (MCF-7), gastric adenocarcinoma (AGS), and human embryonic kidney (HEK293) cells via MTT assay. The results indicated that compound 4r (DHPM derivative) was the most toxic molecule against the MCF-7 cell line (IC 50 of 0.17 μg/mL). Moreover, compounds 4j and 4r (DHPM derivatives) showed excellent cytotoxic activities against the AGS cell line, with an IC 50 of 4.90 and 4.97 μg/mL, respectively. Although they are pyridine derivatives, compounds 5g and 5m were more active against the MCF-7 cell line. Results showed that the candidate compounds exhibited low cytotoxicity against HEK293 cells. The kinesin Eg5 inhibitory potential of the candidate compounds was evaluated by molecular docking. The docking results showed that, among the pyridine derivatives, compound 5m had the most free energy of binding (–9.52 kcal/mol) and lowest Ki (0.105 μM), and among the pyrimidine derivatives, compound 4r had the most free energy of binding (–7.67 kcal/mol) and lowest Ki (2.39 μM). Ligand-enzyme affinity maps showed that compounds 4r and 5m had the potential to interact with the Eg5 binding site via H-bond interactions to GLU116 and GLY117 residues. The results of our study strongly suggest that DHPM and pyridine derivatives inhibit important tumorigenic features of breast and gastric cancer cells. Our results may be helpful in the further design of DHPMs and pyridine derivatives as potential anticancer agents.

Further insight into the dual COX-2 and 15-LOX anti-inflammatory activity of 1,3,4-thiadiazole-thiazolidinone hybrids: The contribution of the substituents at 5th positions is size dependent.

Herin we report the design, synthesis, full characterization and biological investigation of new 15-LOX/COX dual inhibitors based on 1,3-thiazolidin-4-one (15-lipoxygenase pharmacophore) and 1,3,4-thiadiazole (COX pharmacophore) scaffolds. This series of molecular modifications is an extension of a previously reported series to further explore the structural activity relationship. Compounds 3a, 4e, 4n, 4q, 7 and 8 capable of inhibiting 15-LOX at (2.74, 4.2, 3.41, 10.21, 3.71 and 3.36µM, respectively) and COX-2 at (0.32, 0.28, 0.28, 0.1, 0.28 and 0.27µM, respectively). The results revealed that binding to 15-LOX and COX is sensitive to the bulkiness of the substituents at the 5 positions. 15-LOX bind better with small substituents, while COXs bind better with bulky substituents. Compounds 3a, 4r and 4q showed comparable in vivo anti-inflammatory activity to the reference drug (celecoxib). The ulcer liability test showed no sign of ulceration which ensures the safe gastric profile. Docking study was performed to explore the possible mode of interaction of the new compounds with the active site of human 15-LOX and COX-2. This study discloses some structural features for binding to 15-LOX and COX, thus pave the way to design anti-inflammatory agents with balanced dual inhibition of these enzymes.

Pharmacological Inhibition of Cathepsin S Suppresses Abdominal Aortic Aneurysm in Mice

Evidence suggests that cathepsin S (CTSS), a potent mammalian elastase, participates in abdominal aortic aneurysm (AAA) formation. This study examines the hypothesis that pharmacological inhibition of CTSS with an α-ketoamide based compound 6r might suppress AAA in mice. Experimental study of the CaCl2 induced AAA model in B6 mice and angiotensin II (AngII) infused AAA model in ApoE-/- mice. The effects of intraperitoneal administration of 6r (25mg/kg) and vehicle every three days since one day after AAA induction were evaluated at 28 days using CaCl2 induced (n=12 per group) and AngII infused (n=8 per group) models. Additionally, the effects of post-treatment with 6r and vehicle from seven days or 14 days after AAA induction were evaluated at 28 days using the CaCl2 induced model (n=6 per group). Aortic samples were harvested for histological and biochemical analyses, including cathepsin levels, Verhoeff Van Gieson staining, TUNEL assay, and immunostaining for macrophages. In the CaCl2 induced model, treatment with 6r suppressed aortic dilatation observed in vehicle treated controls (median: 0.58 vs. 0.92mm; p<.001), along with reduced CTSS and cathepsin K (CTSK) levels (both p<.001), preserved elastin integrity (p<.001), fewer medial apoptotic cells (p=.012) and less macrophage infiltration (p=.041). In the AngII infused model, the aortic diameter was smaller in 6r treated mice than in vehicle treated controls (median: 0.95 vs. 1.84mm; p=.047). The levels of CTSS (p<.001) and CTSK (p=.033) and the numbers of elastin breaks (p<.001), medial apoptotic cells (p<.001) and infiltrating macrophages (p=.030) were attenuated under 6r treatment. Finally, post-treatment with 6r from seven days (p=.046) or 14 days (p=.012) after AAA induction limited CaCl2 induced AAA. Pharmacological inhibition of CTSS by 6r suppresses AAA formation in mice. Also, post-treatment with 6r retards mouse AAA progression. These findings provide proof of concept validation for CTSS as a potential therapeutic target in AAA.

Design, synthesis and antifungal activity of (E)-3-acyl-5-(methoxyimino)-1,5-dihydrobenzo[e][1,2]oxazepin-4(3H)-one analogues.

Nitrogen- or oxygen-containing organic compounds which have significant antifungal activity, twenty one novel nitrogen or oxygen-containing (E)-3-acyl-5-(methoxyimino)-1,5-dihydrobenzo[e][1,2]oxazepin-4(3H)-one analogues were designed and synthesized, and their structures were confirmed by 1H NMR, 13C NMR and HRMS. Preliminary bioassay showed that most of them exhibited certain-to-good antifungal activity. Compounds 5k-2, 5n, 5p and 5r exhibited over 80% inhibitory rate against Sclerotinia sclerotiorum at 50μg/mL, and 5r exhibited good antifungal activity against S. sclerotiorum with EC50 of 7.21μg/mL. Compounds 5a and 5r also showed over 90% inhibition against Botrytis cinerea. In particular, 5r showed significant higher activity with the lowest EC50 of 7.92μg/mL than the positive control trifloxystrobin (21.96μg/mL) and azoxystrobin (9.43μg/mL). Providing a practical method for the synthesis of new scaffolds 1,2-Benzoxazepinone and systematically investigate their antifungal activity.

Synthesis and X-ray diffraction data of (4R)-methyl-3-(1-(4-chlorophenyl)-1H-1,2,3-triazole-4-carbonyl)thiazolidin-4-carboxylate, C14H13ClN4O3S

The new compound (4R)-methyl-3-(1-(4-chlorophenyl)-1H-1,2,3-triazole-4-carbonyl)thiazolidin-4-carboxylate was synthesized by the 1,3-dipolar cycloaddition reaction between (4R)-methyl-3-propionyl-thiazolidin-4-carboxylate (1) and 4-chlorophenylazide using the click chemistry approach. Molecular characterization was carried out by infrared spectroscopy and mass spectrometry. The X-ray powder diffraction study determined that the title compound crystallized in an orthorhombic system with unit-cell parameters a = 20.876 (2) Å, b = 12.111 (1) Å, and c = 6.288 (9) Å. The volume of the unit cell is V = 1589.7 (2) Å3. All measured diffraction maxima were indexed and are consistent with the P2221 space group (No. 17). No detectable impurities were observed.

Synthesis of Quaternary Carbon-Centered Benzoindolizidinones via Novel Photoredox-Catalyzed Alkene Aminoarylation: Facile Access to Tylophorine and Analogues

Photoredox-catalyzed aminoarylation and thioamination of unactivated alkenes have been developed, providing novel synthetic routes to access synthetically challenging quaternary carbon-centered ben...

Potent combretastatin A-4 analogs containing 1,2,4-triazole: Synthesis, antiproliferative, anti-tubulin activity, and docking study

A series of cis restricted 1,2,4-triazole analogs of combretastatin A-4 (CA-4) were designed and synthesized. The antiproliferative activity of these compounds was measured on hepatocellular carcinoma HepG2, leukemia HL-60, and breast cancer MCF-7 cell lines. The obtained results showed a substantial ability of the synthesized anilides to inhibit tumor growth. On HepG2 cells, 5o and 5r showed potent IC50 values of 0.10 and 0.04 μM, respectively. While on HL-60 cells, the IC50 values were 0.004 and 0.01 μM for 5b and 5i, respectively. The inhibitory activity of tubulin polymerization was evaluated on HepG2 cells. The anilide 5r showed a remarkable tubulin inhibition compared to CA-4. Moreover, flow cytometry studies showed that HepG2 cells treated with the most potent compounds 5b and 5r were arrested in the G2/M phase of the cell cycle. This effect was accompanied by cellular apoptosis and activation of caspase-3. Molecular modeling showed several hydrogen bonding and van der Waals interactions with several important amino acids inside the colchicine binding site of tubulin.

Design, synthesis and biological evaluation of novel diazaspiro[4.5]decan-1-one derivatives as potential chitin synthase inhibitors and antifungal agents

A series of 2,8-diazaspiro[4.5]decan-1-one derivatives were designed, synthesized and screened for their inhibition activities against chitin synthase (CHS) and antimicrobial activities in vitro. The biological assays revealed that compounds 4a, 4e, 4h, 4j, 4o, 4q and 4r exhibited moderated to excellent potency against CHS with IC50 values ranging from 0.12 to 0.29 mM. Compounds 4e, 4j with IC50 value of 0.13 mM, 0.12 mM respectively, showed excellent inhibition potency among these compounds, which were similar to that of polyoxin B whose IC50 value was 0.08 mM. Meanwhile, the screening of the antifungal activity showed that compounds 4j and 4r had the same potency of inhibiting the growth of A. fumigatus with MIC value of 0.08 mmol/L. Compound 4d displayed excellent activity against C. albicans (ATCC 90023) with MIC value of 0.04 mmol/L, which was superior to fluconazole (0.104 mmol/L) and polyoxin B (0.129 mmol/L). The result of antibacterial assay showed that these compounds had little potency against those selected bacteria strains including three Gram-positive bacteria and three Gram-negative bacteria. Furthermore, the combination use of 4c-fluconazole, 4i-fluconazole, 4j-fluconazole, and 4o-fluconazole against C. albicans,A. fumigatus and A. flavus showed additive or synergistic effects. These results indicated that the designed compounds serve as potential chitin synthase inhibitors and have selectively antifungal activities.

Targeting malaria and leishmaniasis: Synthesis and pharmacological evaluation of novel pyrazole-1,3,4-oxadiazole hybrids. Part II

In continuance with earlier reported work, an extension has been carried out by the same research group. Mulling over the ongoing condition of resistance to existing antimalarial agents, we had reported synthesis and antimalarial activity of certain pyrazole-1,3,4-oxadiazole hybrid compounds. Bearing previous results in mind, our research group ideated to design and synthesize some more derivatives with varied substitutions of acetophenone and hydrazide. Following this, derivatives 5a–r were synthesized and tested for antimalarial efficacy by schizont maturation inhibition assay. Further, depending on the literature support and results of our previous series, certain potent compounds (5f, 5n and 5r) were subjected to Falcipain-2 inhibitory assay. Results obtained for these particular compounds further strengthened our hypothesis. Here, in this series, compound 5f having unsubstituted acetophenone part and a furan moiety linked to oxadiazole ring emerged as the most potent compound and results were found to be comparable to that of the most potent compound (indole bearing) of previous series. Additionally, depending on the available literature, compounds (5a–r) were tested for their antileishmanial potential. Compounds 5a, 5c and 5r demonstrated dose-dependent killing of the promastigotes. Their IC50 values were found to be 33.3 ± 1.68, 40.1 ± 1.0 and 19.0 ± 1.47 μg/mL respectively. These compounds (5a, 5c and 5r) also had effects on amastigote infectivity with IC50 of 44.2 ± 2.72, 66.8 ± 2.05 and 73.1 ± 1.69 μg/mL respectively. Further target validation was done using molecular docking studies. Acute oral toxicity studies for most active compounds were also performed.

Synthesis, antimicrobial evaluation and docking study of triazole containing triaryl-1H-imidazole

An efficient route for the synthesis of triazole containing triaryl-1H-imidazole (3a–3r) was achieved involving multicomponent condensation of triazole aldehydes, ammonium acetate and 1,2-dicarbonyl compounds in glacial acetic acid. The structure of newly synthesized imidazoles was established by the FTIR, HRMS and NMR spectra. All the compounds displayed considerable antimicrobial activity against fungal and bacterial strains. The triazolyl imidazole 3p was substantially potent against P. aeruginosa (0.0113 µmol/mL), A. niger (0.0113 µmol/mL) and C. albicans (0.0056 µmol/mL) wherein triazolyl imidazoles 3i was found to be more potent against B. subtilis (0.0122 µmol/mL) & A. niger (0.0121 µmol/mL); and compound 3r was also found to be more potent against S. epidermidis (0.0117 µmol/mL) & C. albicans (0.0058 µmol/mL). As a result of docking studies, the binding affinity of the compound 3o was –9.6 kcal/mol which was even more in comparison to the binding affinity of co-crystallized ligand CBN (–9.4 kcal/mol).

Novel 1,3,4-Oxadiazole Derivatives Containing a Cinnamic Acid Moiety as Potential Bactericide for Rice Bacterial Diseases.

Rice bacterial leaf blight and leaf streak are two important bacterial diseases of rice, which can result in yield loss. Currently, effective antimicrobials for rice bacterial diseases are still lacking. Thus, to develop highly effective and low-risk bactericides, 31 novel 1,3,4-oxadiazole derivatives containing a cinnamic acid moiety were designed and synthesized. Bioassay results demonstrated that all compounds exhibited good antibacterial activities in vitro. Significantly, compounds 5r and 5t showed excellent antibacterial activities against Xanthomonas oryzae pv. oryzae (Xoo) and X. oryzae pv. oryzicola (Xoc), with the 50% effective concentration (EC50) values of 0.58 and 0.34, and 0.44 and 0.20 μg/mL, respectively. These compounds were much better than thiodiazole copper (123.10 and 161.52 μg/mL) and bismerthiazol (85.66 and 110.96 μg/mL). Moreover, compound 5t had better protective and curative activities against rice bacterial leaf blight and leaf streak than thiodiazole copper and bismerthiazol in vivo. Simultaneously, the in vivo efficacy of the compounds was demonstrated by real-time quantitative PCR to quantify bacterial titers. In addition, a three-dimensional quantitative structure–activity relationship model was created and presented good predictive ability. This work provides support for 1,3,4-oxadiazole derivatives containing a cinnamic acid moiety as a potential new bactericide for rice bacterial diseases.

ChCl:2ZnCl2 Catalyzed Efficient Synthesis of New Sulfonyl Decahydroacridine-1,8-Diones via One-Pot Multicomponent Reactions to Discover Potent Antimicrobial Agents

A library of new sulfonyl decahydroacridine-1,8-diones has been efficiently synthesized by the one-pot three-component reactions of 4-(p-tolyl sulfonoxy) benzaldehyde, dimedone, and amines in choline chloride-based deep eutectic mixture. Pure target compounds are obtained in very good to excellent yields over short reaction times using straightforward work-up procedure. The synthesized heterocyclic decahydroacridine-1,8-diones were investigated for their in vitro antimicrobial activity. The minimum inhibitory concentration was determined for the test compounds as well as for reference standards. Compounds 4f, 4m, 4n, and 4o have shown good antibacterial activity whereas compounds 4a, 4c, 4g, 4j, and 4r have displayed better antifungal activity.

Interconversion and reactivity of manganese silyl, silylene, and silene complexes.

Manganese disilyl hydride complexes [(dmpe)2MnH(SiH2R)2] (4Ph : R = Ph, 4Bu : R = n Bu) reacted with ethylene to form silene hydride complexes [(dmpe)2MnH(RHSi[double bond, length as m-dash]CHMe)] (6Ph,H : R = Ph, 6Bu,H : R = n Bu). Compounds 6R,H reacted with a second equivalent of ethylene to generate [(dmpe)2MnH(REtSi[double bond, length as m-dash]CHMe)] (6Ph,Et : R = Ph, 6Bu,Et : R = n Bu), resulting from apparent ethylene insertion into the silene Si-H bond. Furthermore, in the absence of ethylene, silene complex 6Bu,H slowly isomerized to the silylene hydride complex [(dmpe)2MnH([double bond, length as m-dash]SiEt n Bu)] (3Bu,Et ). Reactions of 4R with ethylene likely proceed via low-coordinate silyl {[(dmpe)2Mn(SiH2R)] (2Ph : R = Ph, 2Bu : R = n Bu)} or silylene hydride {[(dmpe)2MnH([double bond, length as m-dash]SiHR)] (3Ph,H : R = Ph, 3Bu,H : R = n Bu)} intermediates accessed from 4R by H3SiR elimination. DFT calculations and high temperature NMR spectra support the accessibility of these intermediates, and reactions of 4R with isonitriles or N-heterocyclic carbenes yielded the silyl isonitrile complexes [(dmpe)2Mn(SiH2R)(CNR')] (7a-d: R = Ph or n Bu; R' = o-xylyl or t Bu), and NHC-stabilized silylene hydride complexes [(dmpe)2MnH{[double bond, length as m-dash]SiHR(NHC)}] (8a-d: R = Ph or n Bu; NHC = 1,3-diisopropylimidazolin-2-ylidene or 1,3,4,5-tetramethyl-4-imidazolin-2-ylidene), respectively, all of which were crystallographically characterized. Silyl, silylene and silene complexes in this work were accessed via reactions of [(dmpe)2MnH(C2H4)] (1) with hydrosilanes, in some cases followed by ethylene. Therefore, ethylene (C2H4 and C2D4) hydrosilylation was investigated using [(dmpe)2MnH(C2H4)] (1) as a pre-catalyst, resulting in stepwise conversion of primary to secondary to tertiary hydrosilanes. Various catalytically active manganese-containing species were observed during catalysis, including silylene and silene complexes, and a catalytic cycle is proposed.

Study on synthesis and biological effects of a series of 3,4-dihydroisoquinoline-2(1H)-carboxamide derivatives

In this paper, we have reported the synthesis and biological evaluation of nineteen (S)-N-substituted-1-phenyl-3,4-dihydroisoquinoline-2(1H)-carboxamide derivatives as novel candidate antidepressant and anticonvulsant agents. Compounds 2h, 2k, 2r, and 2s exhibited better potent antidepressant activity and displayed the antidepressant effects in a dose-dependent manner from 10 to 30 mg/kg in the FST and TST. And, we found that the best antidepressant effect of compounds 2r and 2s are likely mediated by an increase in central nervous system 5-HT and NE. In addition, compounds 2r and 2s also exhibited the anticonvulsant activity against MES-induced seizures. Thus, compounds 2r and 2s may be a useful antidepressant adjunct therapy for treating depression in patients with epilepsy. In addition, compounds 2r and 2s showed the anti-inflammatory activity and the excellent analgesic activity. Several scholars have postulated the anti-inflammatory and analgesic effects of antidepressant drugs, suggesting that they may be possess a similar mechanism of action.

Design, synthesis and biological evaluation of imidazo[1,2-a]pyridine analogues or derivatives as anti-helmintic drug.

The Albendazole was used as the lead compound, which was modified by structural transformation and with alkyl groups. A total of 18 compounds (4a-4r) were designed and synthesized. The in vitro experiment results showed that compounds 4e, 4f, 4k, 4l, 4q and 4r had good inhibitory effect on egg and imago of roundworm. IC50 of compound 4l to anti-egg of roundworm was 0.65±0.01μmol/L and to anti-imago of roundworm was 1.04±0.01μmol/L. At the same time, it showed that compound 4l had the best effect in vivo, and the rate of anti-helmintic could reach more than 99%. The results of acute toxicity tests indicated that these compounds were with LD50 > 2100 mg/kg by oral administration, so they were low toxicity compounds. In a word, compound 4l was most likely to be a new anti-helmintic drug through screening in vitro and in vivo.