Synthesis and Fungicidal Activities of New 1,2,4-Triazolo[1,5-a]pyrimidines

Triazolopyrimidine Derivatives: An Updated Review on Recent Advances in Synthesis, Biological Activities and Drug Delivery Aspects

Molecules containing triazolopyrimidine core showed diverse biological activities, including anti-Alzheimer's, anti-diabetes, anti-cancer, anti-microbial, anti-tuberculosis, anti-viral, anti-malarial, anti-inflammatory, anti-parkinsonism, and anti-glaucoma activities. Triazolopyrimidines have 8 isomeric structures, including the most stable 1,2,4-triazolo[1,5- a] pyrimidine ones. Triazolopyrimidines were obtained by using various chemical reactions, including a) 1,2,4-triazole nucleus annulation to pyrimidine, b) pyrimidines annulation to 1,2,4-triazole structure, c) 1,2,4-triazolo[l,5-a] pyrimidines rearrangement, and d) pyrimidotetrazine rearrangement. This review discusses synthetic methods, recent pharmacological actions and drug delivery perspectives of triazolopyrimidines.

Synthesis of pyrimidine-6-carbonitriles, pyrimidin-5-ones, and tetrahydroquinoline-3-carbonitriles by new superb oxovanadium(V)-[5,10,15,20-tetrakis(pyridinium)-porphyrinato]-tetra(tricyanomethanide) catalyst via anomeric based oxidation

Oxovanadium(V)-[5,10,15,20-tetrakis(pyridinium)-porphyrinato]-tetra(tricyanomethanide) [(VO)TPP][(TCM)₄] was designed, synthesized and characterized by various techniques such as FT-IR, EDX, SEM equipped with EDX mappings, CHN elemental analysis, ICP-OES, XRD, SEM, TEM, TGA, DTA, DRS, Kubelka-Munk function (Tauc's plot), and UV-Vis analyses. Then, [(VO)TPP][(TCM)₄] was used as a benign and expedient catalyst for the synthesis of numerous heterocyclic compounds such as 5-amino-7-(aryl)-4,7-dihydro-[1,2,4]triazolo[1,5-a]pyrimidine-6-carbonitriles, 5-amino-7-(aryl)-[1,2,4]triazolo[1,5-a]pyrimidine-6-carbonitriles, 7-(aryl)-7,12-dihydro-5H-isochromeno[4,3-d][1,2,4]triazolo[1,5-a]pyrimidin-5-ones, and 4-(aryl)-2-(1H-indol-3-yl)-5,6,7,8-tetrahydroquinoline-3-carbonitriles under solvent-free conditions at 100 °C via a cooperative geminal-vinylogous anomeric based oxidation.

An Overview on Synthetic and Medicinal Perspectives of [1,2,4]Triazolo[1,5-a]pyrimidine Scaffold

[1,2,4]Triazolo[1,5-a]pyrimidine is an important heterocyclic scaffold known to have a wide range of pharmacological activities such as anticancer, antimicrobial, anti-tubercular, CB₂ cannabinoid agonists, feticide, and adenosine antagonists. Several clinical trials and marketed drugs such as Trapidil, Essramycin, Pyroxsulam, DSM-265, Flumetsulam, GNF-6702, and Cevipabulin indicate the potential of [1,2,4]triazolo[1,5-a]pyrimidine moiety with various functional groups in medicinal chemistry. Herein, we represent a concise report focusing on the synthetic strategies used for diversely substituted [1,2,4]triazolo[1,5-a]pyrimidine analogs and their pharmacological applications. To the best of our knowledge, since 1980, we are the first to write a review on this emerging scaffold, which reveals the synthetic strategies, and pharmacological activities of differently substituted [1,2,4]triazolo[1,5-a]pyrimidine with special emphasis on structure-activity relationship studies.

Design, synthesis and biological activities of echinopsine derivatives containing acylhydrazone moiety

Based on the broad-spectrum biological activities of echinopsine and acylhydrazones, a series of echinopsine derivatives containing acylhydrazone moieties have been designed, synthesized and their biological activities were evaluated for the first time. The bioassay results indicated that most of the compounds showed moderate to good antiviral activities against tobacco mosaic virus (TMV), among which echinopsine (I) (inactivation activity, 49.5 ± 4.4%; curative activity, 46.1 ± 1.5%; protection activity, 42.6 ± 2.3%) and its derivatives 1 (inactivation activity, 44.9 ± 4.6%; curative activity, 39.8 ± 2.6%; protection activity, 47.3 ± 4.3%), 3 (inactivation activity, 47.9 ± 0.9%; curative activity, 43.7 ± 3.1%; protection activity, 44.6 ± 3.3%), 7 (inactivation activity, 46.2 ± 1.6%; curative activity, 45.0 ± 3.7%; protection activity, 41.7 ± 0.9%) showed higher anti-TMV activity in vivo at 500 mg/L than commercial ribavirin (inactivation activity, 38.9 ± 1.4%; curative activity, 39.2 ± 1.8%; protection activity, 36.4 ± 3.4%). Some compounds exhibited insecticidal activities against Plutella xylostella, Mythimna separate and Spodoptera frugiperda. Especially, compounds 7 and 27 displayed excellent insecticidal activities against Plutella xylostell (mortality 67 ± 6% and 53 ± 6%) even at 0.1 mg/L. Additionally, most echinopsine derivatives exhibited high fungicidal activities against Physalospora piricola and Sclerotinia sclerotiorum.

Synthesis, anticancer activity and molecular docking of new triazolo[4,5-d]pyrimidines based thienopyrimidine system and their derived N-glycosides and thioglycosides

A series of new substituted triazolo[4,5-d]pyrimidine derivatives linked to thienopyrimidine ring system were prepared as a hybrid heterocyclic systems, as possible nucleobases analogs, starting from the key carboxamide derivative 2 and its azide precursor via heterocyclization reactions and their structures were characterized. Glycosylation of the prepared triazolopyrimidine derivatives was performed and afforded, regioselctively, the corresponding thienopyrimidine-triazolopyrimidine hybrid N¹-glycosides and their thioglycoside analogues in good yields. The synthesized glycosyl heterocycles were studied for their cytotoxic activity against HepG-2 and MCF-7 human cancer cells and significant results were obtained. Compounds 7a, 8 b, 9 b, 9a and 7 b demonstrated promising activities comparable to the activity of the doxorubicin for (HepG-2) cell line. Furthermore, a number of the afforded triazolopyrimidine glycosides were found potent against cancer cells (MCF-7). Furthermore, docking simulation the promising thienopyrimidine analogues 7-13 was done against EGFR kinase to provide a binding model that could serve in discovery of further anticancer agents.

Synthesis and Antiviral/Fungicidal/Insecticidal Activities Study of Novel Chiral Indole Diketopiperazine Derivatives Containing Acylhydrazone Moiety

On the basis of the mechanism of acylhydrazone compounds inhibiting the assembly of TMV CP and the unique structural characteristics of diketopiperazine ring, a series of optically pure indole diketopiperazine acylhydrazone were designed and synthesized. In order to systematically study the effect of the spatial configuration of the compounds on the antiviral activity, four compounds with different spatial configurations at C6 and C12a were also prepared. The bioassay results indicated that most of these new compounds displayed moderate to good antiviral activity, among which compounds 23, 25, 27, 28, 31, and 5d showed a significantly higher activity than that of commercial ribavirin. An in-depth structure-activity relationship investigation showed that the spatial conformation was one of the most important factors in adjusting antiviral activity; the research results provided information about the possible optimum configuration for interaction of this molecular with its target protein. At the same time, these new compounds also exhibited broad-spectrum fungicidal activities against 14 kinds of phytopathogenic fungi. What's more, some of these compounds exhibited good insecticidal activity to Plutella xylostella and Culex pipiens pallens.

Design, Synthesis, and Biological Activities of Spirooxindoles Containing Acylhydrazone Fragment Derivatives Based on the Biosynthesis of Alkaloids Derived from Tryptophan

On the basis of the biosynthesis of alkaloids derived from tryptophan and considering the wide use of spirooxindole in drug molecular design, a series of novel spirooxindole derivatives containing an acylhydrazone moiety were designed, synthesized, and first evaluated for their biological activities. The results of bioassays indicated that the target compounds possessed good activities against tobacco mosaic virus (TMV); especially compound 4, containing a tert-butyl at the benzene ring, exhibited the best antiviral activity in vitro and inactivation, curative, and protection activities in vivo (48.4%, 58 ± 0.4, 55.2 ± 2.3, and 49.7 ± 1.1% at 500 μg/mL, respectively) compared with ribavirin (38.2, 36.4 ± 0.2, 37.5 ± 0.2, and 36.4 ± 0.1% at 500 μg/mL, respectively) and harmine (44.6, 40.5 ± 0.2, 38.6 ± 0.8, and 42.4 ± 0.6% at 500 μg/mL, respectively). At the same time, these compounds exhibited fungicidal activity selectively against certain fungi; most of these derivatives exhibited >60% fungicidal activity against Physalospora piricola at 50 mg/kg. Additionally, compounds 25 and 14 displayed excellent insecticidal activities (60% motality against C. pipiens pallens at 0.25 mg/kg) even at very low concentrations.

Design, synthesis, and antiviral, fungicidal, and insecticidal activities of tetrahydro-β-carboline-3-carbohydrazide derivatives

According to our previous research on the antiviral activity of β-carboline and tetrahydro-β-carboline derivatives, using (1S,3S)-1-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carbohydrazide (1) as a lead compound, series of novel tetrahydro-β-carboline derivatives containing acylhydrazone moiety were designed, synthesized, and first evaluated for their biological activities. Most of these compounds exhibited excellent antiviral activity both in vitro and in vivo. The in vivo inactivation, curative, and protection activities of compounds 8, 9, 12, 16, 28, 29, and 30 were much higher than that of ribavirin (37.6%, 39.4%, and 37.9% at 500 μg/mL) and the lead compound (40.0%, 42.3%, and 39.6% at 500 μg/mL). Especially, the in vitro and in vivo activities of compound 16 (36.9%, 33.6%, 30.2%, and 35.8%) at 100 μg/mL, which were very close to that of ribavirin (40.0% for in vitro activity) at 500 μg/mL. Compounds 9 and 29 were chosen for the field trials of antiviral efficacy against TMV (tobacco mosaic virus); the results exhibited that both compounds, especially compound 29, showed better activities than control plant virus inhibitors. At the same time, the fungicidal results showed that compounds 6, 9, and 11 exhibited good fungicidal activities against 14 kinds of phytopathogens. Additionally, compounds 3 and 23 exhibited moderate insecticidal activity against the four tested species of insects.

In vitro and in vivo antiparasital activity against Trypanosoma cruzi of three novel 5-methyl-1,2,4-triazolo[1,5-a]pyrimidin-7(4H)-one-based complexes

Conventional reactions of the versatile multidentate ligand 5-methyl-1,2,4-triazolo[1,5-a] pyrimidin-7(4H)-one (HmtpO) with metallic(II) perchlorate salts lead to three novel multidimensional complexes [Cu(HmtpO)(2)(H(2)O)(3)](ClO(4))(2)·H(2)O (1), {[Cu(HmtpO)(2)(H(2)O)(2)](ClO(4))(2) ·2HmtpO}(n) (2) and {[Co(HmtpO)(H(2)O)(3)](ClO(4))(2)·2H(2)O}(n) (3). We have tested the antiparasital activity in vitro and in vivo of the three new complexes against Trypanosoma cruzi showing very promising results and overcoming clearly the reference drug commonly used for the Chagas disease treatment, benznidazole.