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Vilsmeier–Haack formylation of 3-aminothiazolotriazolopyridine-7,9-dicarbonitrile 3 afforded the corresponding aldehyde derivative 4 in a 65% yield. Some Schiff bases 5-7 were efficiently synthesized by reacting substrate 4 with some primary amines. Reaction of substrate 4 with some active methylene nitriles produced 2-amino-3-substituted-pyridotriazolothiazolopyridines 8–12. Substrate 4 was utilized as a key intermediate for a diversity of pyridotriazolothiazolopyrazolopyridines 13–15, through the Friedlander reaction with pyrazolidine-3,5-dione, 5-amino-2,4-dihydro-3H-pyrazol-3-one, and 5-phenyl-2,4-dihydro-3H-pyrazol-3-one. Further, the reaction of substrate 4 with 5-amino-3-methyl-1H-pyrazole and 6-aminouracil, as cyclic enamines, produced pyridotriazolothiazolopyrazolopyridine 16 and pyridotriazolothiazolopyridopyrimidine 17, respectively. The antimicrobial efficiency was assessed for the synthesized products, and some of them showed notable activity. The structures of the synthesized products were confirmed using analytical and spectroscopic data. [ABSTRACT FROM AUTHOR]

Quinolines are very important materials in organic synthesis due to their wide range of biological activities as well as representing one of the most research area in medicinal chemistry. Quinolines have many applications in design and synthesis of multiple heterocyclic compounds with a wide variety of biological significance. Quinolines fused heterocycles at face b using different synthetic methodologies as well as variable precursors and reaction conditions were the aim of the current review. [ABSTRACT FROM AUTHOR]

2-Chloropyridine-3-carbonitrile derivative 1 was utilized as a key precursor to build a series of linear and angular annulated pyridines linked to a 6-hydroxy-4,7-dimethoxybenzofuran moiety. Reaction of substrate 1 with various hydrazines afforded pyrazolo[3,4-b]pyridines. Treatment of substrate 1 with 1,3-N,N-binucleophiles including 3-amino-1,2,4-triazole, 5-amino-1H-tetrazole, 3-amino-6-methyl-1,2,4-triazin-5(4H)-one and 2-aminobenzimidazole produced the novel angular pyrido[3,2-e][1,2,4]triazolo[4,3-a]pyrimidine, pyrido[3,2-e][1,2,4]tetrazolo[1,5-a]pyrimidine, pyrido[3′,2′:5,6] pyrimido[2,1-c][1,2,4]triazine and benzo[4,5]imidazo[1,2-a]pyrido[3,2-e]pyrimidine, respectively. Reaction of substrate 1 with 1,3-C,N-binucleophiles including cyanoacetamides and 1H-benzimidazol-2-ylacetonitrile furnished 1,8-naphthyridines and benzoimidazonaphthyridine. Moreover, reacting substrate 1 with 5-aminopyrazoles gave pyrazolo[3,4-b][1,8]naphthyridines. Finally, reaction of compound 1 with 6-aminouracils as cyclic enamines yielded pyrimido[4,5-b][1,8]naphthyridines. Some of the synthesized products showed noteworthy antimicrobial efficiency against all types of microbial strains. Structures of the produced compounds were established using analytical and spectroscopic tools. [ABSTRACT FROM AUTHOR]

2-Chloro-5-[(6-hydroxy-4,7-dimethoxy-1-benzofuran-5-yl)carbonyl]pyridine-3-carbonitrile (3) was synthesized and its chemical reactivity was investigated toward a diversity of binucleophiles. Treatment of compound 3 hydrazine hydrate and phenylhydrazine produced pyrazolo[3,4-b]pyridines while isoxazolo[5,4-b]pyridine was obtained from reacting compound 3 with hydroxylamine. A diversity of pyrido[2,3-d]pyrimidines was synthesized from treatment of staring substrate 3 with some 1,3-N,N-binucleophiles. Treating compound 3 with some 1,4-binucleophiles including ethylenediamine, o-phenylenediamine, 2-aminophenol and 2-aminothiophenol furnished pyrido[2,3-e][1,4]diazepine 12 and pyrido[2,3-b][1,5] benzodiazepine 13, pyrido[2,3-b][1,5]benzoxazepine 14 and pyrido[2,3-b][1,5] benzothiazepine 15, respectively. The synthesize compounds shown remarkable effect against yeast and fungus, while compounds 4 and 7–11 exhibit excellent efficacy against all types of Gram + and Gram - bacteria. Structures of the produced compounds were established using analytical and spectroscopic tools. [ABSTRACT FROM AUTHOR]

The goal of this study was directed to synthesize a novel class of annulated compounds containing difuro[3,2-c:3′,2′-g]chromene. Friedländer condensation of o-aminoacetyl derivative 3 was performed with some active methylene ketones, namely, 1,3-cyclohexanediones, pyrazolones, 1,3-thiazolidinones and barbituric acids, furnished furochromenofuroquinolines (4,5), furochromenofuropyrazolopyridines (6–8), furochromenofurothiazolopyridines (9,10) and furochromenofuropyridopyrimidines (11, 12), respectively. Also, condensation of substrate 3 with 5-amine-3-methyl-1H-pyrazole and 6-amino-1,3-dimethyluracil, as cyclic enamines, resulted in polyfused systems 13 and 14, respectively. In vitro antimicrobial efficiency of the prepared heterocycles against microbial strains exhibited variable inhibition action, where compound 3 was the most effective against all kinds of microorganisms. A significant cytotoxic activity was seen upon the annulation of the starting compound with thiazolopyridine (9 and 10) as well as pyridopyrimidine moieties (11, 12 and 14). The spectroscopic and analytical results were used to infer the structures of the novel synthesized compounds. [ABSTRACT FROM AUTHOR]

The novel chromonyltriazolo[3,4-b][1,3,4]thiadiazole derivative 5 was efficiently synthesized and utilized as key intermediate for construction of a diversity of heterocyclic rings; through reactions with binucleophilic reagents. Treating electron deficient substrate 5 with hydrazine hydrate, phenylhydrazine and hydroxylamine furnished pyrazolyl/isoxazolyltriazolo[3,4-b][1,3,4]thiadiazoles 6-8. Also, reacting substrate 5 with guanidine, cyanoguanidine and thiourea provided pyrimidinyltriazolo[3,4-b][1,3,4]thiadiazoles 9-11. Reaction of substrate 5 with ethylenediamine and o-phenylenediamine afforded diazepine derivatives 12 and 13. Reaction of substrate 5 with malononitrile, ethyl cyanoacetate and cyanoacetamide afforded pyrans 14, 15 and pyridine 16 linked triazolo[3,4-b][1,3,4]thiadiazolyl chromeno[2,3-b]pyridines. The anticancer efficiency of the current compounds presented diverse inhibitory action against certain cancer cell lines. On the basis of analytical and spectral findings, the structures of the synthesized products were confirmed. [ABSTRACT FROM AUTHOR]

Breast cancer is a serious threat to the health and lives of women. Two novel series of N′-(2-oxoindolin-3-ylidene)-6-methylimidazo[2,1-b]thiazole-5-carbohydrazides and 1-(aryl)-3-(6-methylimidazo[2,1-b]thiazol-5-yl)ureas were designed, synthesized and investigated for their anticancer efficacy against the MCF-7 breast cell line. Three compounds of the first series showed potent activity toward MCF-7 with IC50 in the range 8.38–11.67 µM, respectively, as compared to Sorafenib (IC50 = 7.55 µM). N′-(1-butyl-2-oxoindolin-3-ylidene)-6-methylimidazo[2,1-b]thiazole-5-carbohydrazide inhibited VEGFR-2 with IC50 = 0.33 µM when compared with Sorafenib (IC50 = 0.09 µM). Furthermore, this compound was introduced to PCR assessment, where it increased Bax, caspase 8, caspase 9 and cytochrome C levels by 4.337-, 2.727-, 4.947- and 2.420-fold, respectively, while it decreased levels of Bcl-2, as the anti-apoptotic gene, by 0.359-fold when compared to the untreated control MCF-7. This compound was also arrested in the G2/M phase by 27.07%, compared with 11.31% for the control MCF-7. Furthermore, it induced early and late apoptosis in MCF-7. In addition, a molecular docking study in the VEGFR-2 active site was performed to assess the binding profile for the most active compounds. Moreover, ADME parameters of the targeted compounds were also evaluated. [ABSTRACT FROM AUTHOR]

The present work aimed at differentiating five Amaranthus species from Saudi Arabia according to their morphology and the ability in nanoparticle formulation. Biogenic silver nanoparticles (AgNPs) were synthesized from leaf extracts of the five Amaranthus species and characterized by different techniques. Fourier-transform infrared spectroscopy (FT-IR) was used to identify the phyto-constituents of Amaranthus species. The nanoparticles (NPs) were characterized by UV-visible spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). The antibacterial activity of the synthesized NPs was tested against Staphylococcus aureus, E. coli, Klebsiella pneumoniae and Pseudomonas aeruginosa using the agar well diffusion method. Spherical NPs varying in size and functional groups from the five plant species were demonstrated by TEM, DLS and FTIR analysis, respectively. Variations in NPs characteristics could be related to the phytochemical composition of each Amaranthus species since they play a significant role in the reduction process. EDX confirmed the presence of Ag in plant fabricated AgNPs. Antibacterial activity varied among the species, possibly related to the NPs characteristics. Varied characteristics for the obtained AgNPs may reflect variations in the phytochemical composition type and concentration among Amaranthus species used for their fabrication. [ABSTRACT FROM AUTHOR]

The essential aim of the present study is designed to utilize 4,9-dimethoxy-5-oxo-5H-furo[3,2-g]chromene-6-carbonitrile (1) to build some novel heterocyclic systems containing benzofurans as well as furo[3,2-g]chromenes. Ring opening ring closure reactions of compound 1 with N-phenyl-2-cyanoacetamide produced 8-amino-furochromenopyridine-7-carboxamide 2, which cyclized with some electrophilic reagents giving furochromenopyridopyrimidines (63–73% yields). The reaction of carbonitrile 1 with pyrazolone derivatives yielded furochromenopyrazolopyridines 10 and 11 in good yields. Also, benzo[h]furochromeno naphthyridine 13 was synthesized from recyclization of carbonitrile 1 with 1-ethyl-4-hydroxyquinolin-2(1H)-one (12). On a different mechanism, recyclization of carbonitrile 1 with some 1,3-binucleophiles afforded pyrido[2,3-d]pyrimidines (14 and 15), pyrimido[1,2-a]pyrimidine 17 and pyrimido[2,1-c][1,2,4]triazine 19 in suitable yields (62–71%). Finally, the reaction of carbonitrile 1 with 1,3-cyclohexanedione and 1,4-cyclohexanedione in 2:1 molar ratio yielded polyfused systems 20 and 21, respectively. Based on spectral and analytical results, the structures of the all products were inferred. [ABSTRACT FROM AUTHOR]

The chemical reactivity of 2-methylchromone-3-carbonitrile (1) was investigated toward a diversity of active methylene nucleophiles. Ring-opening followed by recyclization reactions of compound 1 with some active methylene nitriles afforded 2-amino-3-substituted-4-methylchromeno[2,3-b]pyridin-5-ones. Also, reactions of carbonitrile 1 with some active methylene ketones produced 2,4-dimethylchromeno [2,3-b]pyridin-5-ones. Annulated chromeno[2,3-b]pyrazolo[4,3-e]pyridine, chromeno[2,3-b][1,3]thiazolo[5,4-e]pyridine and chromeno[2,3-b]quinoline were efficiently synthesized from reaction of carbonitrile 1 with some cyclic methylene compounds. Heteroannulated chromeno[3′,2′:5,6]pyrido[2,3-d]pyrimidines and chromeno[2,3-b][1,8]naphthyridines were synthesized from reaction of compound 2 with formic acid, formamide, and malononitrile, cyanoacetamide, respectively. Chromeno[2′,3′:6,5]pyrido[2,3-b][1,8]naphthyridine 17 was synthesized from reaction of compound 2 with malononitrile dimer. Structures of the newly synthesized products were deduced based on their analytical and spectral data. [ABSTRACT FROM AUTHOR]

The present work is directed to synthesize and evaluate the antimicrobial activity of some novel 2-heteroarylchromeno[2,3-d]pyrimidines. 2-(6,8-Dimethylchromon-3-yl)-8-methoxy-4H-chromeno[2,3-d]pyrimidine-4,5(3H)-dione (4) was successfully synthesized and utilized as a building block to produce a variety of heterocyclic compounds. 2-(4-Pyrazolyl/isoxazolyl)chromeno[2,3-d]pyrimidines 5–7 were obtained from the reaction of compound 4 with hydrazine hydrate, phenylhydrazine, and hydroxylamine, respectively. Also, 2-(6-pyrimidinyl)chromeno[2,3-d]pyrimidines 8–12 were efficiently prepared from reacting compound 4 with guanidine, cyanoguanidine, thiourea, acetamidine, and benzamidine, respectively. Further, chromeno[2,3-d]pyrimidines linked diazepine 13, benzodiazepine 14, benzoxazepine 15 and benzothiazepine 16 were also synthesized. The synthesized compounds were examined for their antimicrobial efficiency. Pyrazolylchromeno[2,3-d]pyrimidines 5 and 6 showed the best activity against all kinds of microorganisms. Structures of the synthesized compounds were validated using analytical and spectral data. [ABSTRACT FROM AUTHOR]

A new N,N′-disubstituted piperazine conjugated with 1,3,4-thiadiazole and 1,2,4-triazole was prepared and the chemical structures were identified by IR, NMR and elemental analysis. All the prepared compounds were tested for their antimicrobial activity. The antimicrobial results indicated that the tested compounds showed significant antibacterial activity against gram-negative strains, especially E. coli, relative to gram-positive bacteria. Docking analysis was performed to support the biological results; binding modes with the active site of enoyl reductase amino acids from E. coli showed very good scores, ranging from −6.1090 to −9.6184 kcal/mol. Correlation analysis was performed for the inhibition zone (nm) and the docking score. [ABSTRACT FROM AUTHOR]