Synthesis and Antimicrobial Activity of 2‐(4‐(Hydroxyalkyl)‐1H‐1,2,3‐triazol‐1‐yl)‐N‐substituted propanamides

A series of 21 2‐(4‐(hydroxyalkyl)‐1H ‐1,2,3‐triazol‐1‐yl)‐N ‐substituted propanamides (1,4‐disubstituted 1,2,3‐triazoles having amide linkage and hydroxyl group) have been synthesized from click reaction between terminal alkyne and 2‐azido‐N ‐substituted propanamide (generated in situ from reaction of 2‐bromo‐N ‐substituted propanamide and sodium azide) and characterized by FTIR, ¹H NMR, ¹³C NMR spectroscopy, and HRMS. All the newly synthesized triazoles were tested in vitro for antimicrobial activity against four bacterial cultures – Escherichia coli , Enterobacter aerogenes , Klebsiella pneumoniae , and Staphylococcus aureus – and two fungal cultures – Candida albicans and Aspergillus niger . The synthesized 1,4‐disubstituted 1,2,3‐triazoles displayed moderate to good antimicrobial potential against the tested strains.     

Design,Synthesis and Antifungal Evaluation of N‐Substituted‐1‐(3‐chloropyridin‐2‐yl)‐N‐(pyridin‐4‐yl)‐5‐(trifluoromethyl)‐1H‐pyrazole‐4‐carboxamide Derivatives

A series of 1‐(3‐chloropyridin‐2‐yl)‐5‐(trifluoromethyl)‐1H‐pyrazole‐4‐carboxamide derivatives which have di‐substituents on nitrogen were designed and synthesized. Bioassay results showed that all the synthetic compounds exhibited lower antifungal activities against Gibberella zeae, Cytospora mandshurica, and Fusarium oxysporum than T ₃ (14.7, 21.1, and 32.7 μg/mL), but some of them exhibited better activities against Botrytis cinerea, Phytophthora infestans, and Sclerotinia sclerotiorum than T ₃ (>200, >200, and >200 μg/mL); the EC₅₀ values of 7d and 7c against B. cinerea were 94.9 and 56.2 μg/mL, respectively. The EC₅₀ values of 7a , 7d , and 7c against S. sclerotiorum were 73.5, 78.7, and 68.5 μg/mL, respectively.     

Synthesis and Antimicrobial Activity of 2‐(Pyridine‐3‐yl)‐4H‐chromen‐4‐one Derivatives

An efficiently synthesis of chromones via cyclodehydration of corresponding 1‐(2‐hydroxyphenyl)‐3‐(pyridine‐3‐yl)propane‐1,3‐dione is described under ultrasound irradiation. A series of novel 2‐(pyridine‐3‐yl)‐4H‐chromen‐4‐one derivatives was confirmed on the basis of ¹H‐NMR, mass, IR spectral data, and elemental analysis. The synthesized compounds were evaluated for their antibacterial and antifungal activities. Most of the compounds were found to be comparable potent than the reference standard drugs. Utilization of ultrasound irradiation, simple reaction conditions, isolation, and purification makes this manipulation very interesting from an economic and environmental perspective.     

Synthesis and Antimicrobial Activity of Novel 2‐Substituted Phenoxy‐N‐(4‐substituted Phenyl‐5‐(1H‐1,2,4‐triazol‐1‐yl)thiazol‐2‐yl)acetamide Derivatives

A series of 2‐substituted phenoxy‐N‐(4‐substituted phenyl‐5‐(1H‐1,2,4‐triazol‐1‐yl)thiazole‐2‐yl)acetamide derivatives 8a , 8b , 8c , 8d , 8e , 8f , 8g , 8h , 8i , 8j , 8k , 8l , 8m , 8n , 8o , 8p , 8q , 8r , 8s , 8t was synthesized by the reaction of phenoxyacetyl chloride 7 with intermediate 4‐substituted phenyl‐5‐(1H‐1,2,4‐triazol‐1‐yl)thiazol‐2‐amine 5 . Their structures were confirmed by ¹H NMR, ¹³C NMR, MS, IR, and elemental analyses. The synthesized compounds were also screened for their antimicrobial activity against three types of plant fungi (Gibberella zeae , Phytophthora infestans , and Paralepetopsis sasakii ) and two kinds of bacteria [Xanthomonas oryzae pv. oryzae (Xoo ) and Xanthomonas axonopodis pv. citri (Xac )] showing promising results. In particular, 8b , 8f , 8g , and 8h exhibited excellent antibacterial activity against Xoo , with 50% effective concentration (EC₅₀) values of 35.2, 80.1, 62.5, and 82.1 µg/mL, respectively, which are superior to the commercial antibacterial agent bismerthiazol (89.9 µg/mL). The preliminary structure–activity relationship studies of these compounds are also briefly described.     

Synthesis and Antimicrobial Activity of 4‐(10H‐Phenothiazin‐2‐yl)‐pyrimidin‐2(1H)‐one/thione Derivatives

A series of chalcones 3a , 3b , 3c , 3d containing phenothiazine nucleus were prepared by Claisen–Schmidt condensation. The chalcones on treatment with urea, thiourea, phenyl urea, and phenyl thiourea in alcoholic KOH yielded compounds 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j , 4k , 4l , 4m , 4n , 4o , 4p , and the structures of these compounds were confirmed by spectral and elemental analyses. The newly synthesized compounds were evaluated for antimicrobial activity.     

Exo conformers of N‐(pyridin‐2‐yl)‐ and N‐(pyridin‐3‐yl)norbornene‐5,6‐dicarboximide crystals

Two isomeric pyridine‐substituted norbornenedicarboximide derivatives, namely N‐(pyridin‐2‐yl)‐exo‐norbornene‐5,6‐dicarboximide, (I), and N‐(pyridin‐3‐yl)‐exo‐norbornene‐5,6‐dicarboximide, (II), both C₁₄H₁₂N₂O₄, have been crystallized and their structures unequivocally determined by single‐crystal X‐ray diffraction. The molecules consist of norbornene moieties fused to a dicarboximide ring substituted at the N atom by either pyridin‐2‐yl or pyridin‐3‐yl in an anti configuration with respect to the double bond, thus affording exo isomers. In both compounds, the asymmetric unit consists of two independent molecules (Z′ = 2). In compound (I), the pyridine rings of the two independent molecules adopt different conformations, i.e. syn and anti, with respect to the methylene bridge. The intermolecular contacts of (I) are dominated by C—H...O interactions. In contrast, in compound (II), the pyridine rings of both molecules have an anti conformation and the two independent molecules are linked by carbonyl–carbonyl interactions, as well as by C—H...O and C—H...N contacts.     

Synthesis of Some 3‐(4‐Aryl‐benzofuro[3,2‐b]pyridin‐2‐yl)coumarins and Their Antimicrobial Screening

The synthesis of some 3‐(4‐aryl‐benzofuro[3,2‐b]pyridin‐2‐yl)coumarins 3a–r has been carried out by the reaction of 3‐coumarinoyl methyl pyridinium salts 1a–c with 2‐arylidene aurones 2a–f in the presence of ammonium acetate and acetic acid under Kröhnke's reaction conditions. All the synthesized compounds were characterized by analytical and spectral data. They have been screened for their antibacterial activity against Escherichia coli (ATCC 25922) as Gram‐negative bacteria, Bacillus subtillis (ATCC 1633) as Gram‐positive bacteria and antifungal activity against Aspergillus niger (ATCC 9029).     

Synthesis and Antimicrobial Screening of Some Novel 2‐(5‐(4‐(1H‐Benzo[d][1,2,3]triazol‐1‐yl)phenyl)‐4,5‐dihydro‐1H‐pyrazol‐3‐yl)phenols Incorporated by Triazole Moiety

A novel series of 2‐(5‐(4‐(1H‐benzo[d][1,2,3]triazol‐1‐yl)phenyl)‐4,5‐dihydro‐1H‐pyrazol‐3‐yl)phenols derivative has been synthesized from (E)‐3‐(4‐(1H‐benzo[d][1,2,3]triazol‐1‐yl)phenyl)‐1‐(2‐hydroxyphenyl)prop‐2‐en‐1‐ones in ethanol and hydrazine hydrate under reflux condition. The synthesized compounds were screened for antibacterial activity against Gram‐positive bacteria viz Staphylococcus aureus and Bacillus subtilis and Gram‐negative bacteria viz Escherichia coli and Salmonella typhi, respectively. Some of the tested compounds showed significant antimicrobial activity. IR, ¹H NMR, mass spectral data, and elemental analysis elucidated the structures of all the newly synthesized compounds.     

Synthesis and Antibacterial Activities of 2‐(1‐Aryl‐5‐Methyl‐1,2,3‐triazol‐4‐yl)‐1,3,4‐Oxadiazole Derivatives

Eighteen novel 2‐(1‐aryl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐1,3,4‐oxadiazole derivatives and two acylhydrazone intermediate compounds were synthesized by various pathways starting from 1‐aryl‐5‐methyl‐1,2,3‐triazol‐4‐formhydrazide ( 1 ). All products were identified by spectroscopic analysis, and 2‐(1‐aryl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐5‐benzalthio‐1,3,4‐oxadiazole was further validated by X‐ray crystallography. Results from primary antibacterial activity tests indicated that most of the compounds were effective against E. coli, P. aeruginosa, B. subtilis and S. aureus.     

Synthesis and Cytotoxicity in Vitro of N‐Aryl‐4‐(tert‐butyl)‐5‐(1H‐1,2,4‐triazol‐1‐yl)thiazol‐2‐amine

A series of novel N‐aryl‐4‐(tert‐butyl)‐5‐(1H‐1,2,4‐triazol‐1‐yl)thiazol‐2‐amines synthesized in a green way. H₂O₂‐NaBr Brominating circulatory system was used in the synthesis of the key intermediate in a mild condition. All of the target compounds were confirmed by ¹H NMR and elemental analysis and tested for their cytotoxicity against two different human cancer cell lines. The cytotoxicity assay revealed that some of the title compounds showed moderate to strong cytotoxic activities. Compound 2i was the most potent compound with the IC₅₀ values of 9 μM against Hela cells and 15 μM against Bel–7402 cells, respectively.     

Synthesis and Biological Activity of 1‐(Substituted phenoxyacetoxy)‐1‐(pyridin‐2‐yl or thien‐2‐yl)methylphosphonates

A series of novel O,O‐dimethyl 1‐(substituted phenoxyacetoxy)‐1‐(pyridin‐2‐yl or thien‐2‐yl)methylphosphonates 6a , 6b , 6c , 6d , 6e , 6f , 6g , 6h , 6i , 6j , 6k , 6l , 6m , 6n and 7a , 7b , 7c , 7d were synthesized. Their structures were confirmed by IR, ¹H NMR, mass spectroscopy, and elemental analyses. The results of preliminary bioassays show that some of the title compounds exhibit moderate to good herbicidal and fungicidal activities. For example, the title compounds 6a , 6c , 6l , 6m , and 7d possess 90–100% inhibition against most of the tested plants at the dosage of 1500 g ai/ha, whereas the title compounds 6b , 6g , 6h and 6n possess 92–100% inhibition against Fusarium oxysporum, Phyricularia grisea, Botrytis cinereapers, Gibberella zeae, Sclerotinia sclerotiorum, and Cercospora beticola at the concentration of 50 mg/L.     

Synthesis of (3,5‐Aryl/methyl‐1H‐Pyrazol‐1‐yl)‐(5‐Arylamino‐2H‐1,2,3‐Triazol‐4‐yl)Methanone

Some new (3,5‐aryl/methyl‐1H‐pyrazol‐1‐yl)‐(5‐arylamino‐2H‐1,2,3‐triazol‐4‐yl)methanones were synthesized and characterized by ¹HNMR, ¹³C NMR, MS, IR spectra data and elemental analyses or high resolution mass spectra (HRMS). During the procedure, Dimroth rearrangement was used in this synthesis.     

An Efficient Synthesis of New 5‐(1‐Aryl‐1H‐pyrazole‐4‐yl)‐1H‐tetrazoles from 1‐Aryl‐1H‐pyrazole‐4‐carbonitriles via [3 + 2] Cycloaddition Reaction

A series of new 5‐(1‐aryl‐1H‐pyrazole‐4‐yl)‐1H‐tetrazoles 4a‐l were synthesized via [3 + 2] cycloaddition reaction from 1‐aryl‐1H‐pyrazole‐4‐carbonitriles 3a‐l , sodium azide and ammonium chloride, using dimethylformamide (DMF) as solvent, in good yields: 64–85%. The structures of these newly synthesized compounds were determined from the IR, ¹H‐ and ¹³C‐NMR spectroscopic data and elemental analyses.     

The Synthesis of Some New (S)‐1‐Aryl‐N‐(1‐hydroxy‐3‐phenylpropan‐2‐yl)‐5‐methyl‐1H‐1,2,3‐triazole‐4‐carboxamide

Some new (S)‐1‐aryl‐N‐(1‐hydroxy‐3‐phenylpropan‐2‐yl)‐5‐methyl‐1 H‐1,2,3‐triazole‐4‐carboxamides 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j have been synthesized and established by ¹H and ¹³C NMR, IR, MS spectra, CHN analyses, and x‐ray diffraction crystallography. The molecular conformation and packing is stabilized by interactions of intermolecular H‐bond O2’‐H2'···O1, O2‐H2···O1’ and intramolecular H‐bond N4’‐H4'N···N3’, N4’‐H4'N···O2’, N4‐H4N···N3, N4‐H4N···O2. The two rings of five numbers were formed by H‐bond in a molecular.     

Synthesis and Antimicrobial Activity of New Substituted 5‐(Pyridine‐3‐yl)‐1,3,4‐Thiadiazoles and Their Sugar Derivatives

New substituted 5‐(pyridine‐3‐yl)‐1,3,4‐thiadiazoles, their sugar hydrazones and acyclic C‐nucleoside analogs as well as the corresponding thioglycoside derivatives were synthesized. The synthesized compounds were tested for their antimicrobial activity against Escherichia coli, Bacillus subtilis, Staph aureus, Aspergillus niger, and Candida albicans The obtained results indicated that most of tested compounds exhibited moderate to high antimicrobial activity while few compounds were found to exhibit little or no activity against the tested microorganisms.     

Synthesis and Fungicidal Activity of 5‐Aryl‐1‐(aryloxyacetyl)‐3‐(tert‐butyl or phenyl)‐4‐(1H‐1,2,4‐triazol‐1‐yl)‐4,5‐dihydropyrazole

A series of novel 5‐aryl‐1‐(aryloxyacetyl)‐3‐(tert‐butyl or phenyl)‐4‐(1H‐1,2,4‐triazol‐1‐yl)‐4,5‐dihydropyrazole 3a – 3n were synthesized by the annulation of 2‐aryloxyacetohydrazides with 3‐aryl‐1‐t‐butyl (or phenyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)prop‐2‐en‐1‐ones ( 2 ) in the presence of a catalytic amount of acetic acid. Compounds 2 were obtained by the Knoevenagel reactions of 1‐t‐butyl (or phenyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)ethanone ( 1 ) with aromatic aldehydes in the presence of piperidine. Their structures were confirmed by IR, ¹H‐NMR, ESI‐MS, and elemental analyses. The preliminary bioassay indicated that some compounds displayed moderate to excellent fungicidal activity. For example, compounds 3l , 3m , and 3n possessed 100% inhibition against Cercospora arachidicola Hori at the concentration of 50 mg/L.     

Synthesis and Antimicrobial Evaluation of (1‐(2‐(Benzyloxy)‐2‐oxoethyl)‐1H‐1,2,3‐triazol‐4‐yl)methyl Benzoate Analogues

A convenient one pot synthesis of 20 (1‐(2‐(benzyloxy)‐2‐oxoethyl)‐1H‐1,2,3‐triazol‐4‐yl)methyl benzoate analogues ( 5a – 5t ) with ester functionality was carried out via Cu(I) catalyzed click reaction between prop‐2‐yn‐1‐yl benzoates and benzyl 2‐azidoacetates. The structure of synthesized triazoles were explicated by various spectral techniques like FT‐IR, ¹H NMR, ¹³C NMR, and high‐resolution mass spectrometry and evaluated for in vitro antimicrobial potential against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Enterobacter aerogenes, Candida albicans, and Aspergillus niger. Most of synthesized triazole derivatives exhibited average to excellent activity against tested microbial strains.     

ZnII and CuII complexes generated from 5‐(pyridin‐4‐yl)‐3‐[2‐(pyridin‐4‐yl)ethyl]‐1,3,4‐oxadiazole‐2(3H)‐thione

A new 1,3,4‐oxadiazole‐containing bispyridyl ligand, namely 5‐(pyridin‐4‐yl)‐3‐[2‐(pyridin‐4‐yl)ethyl]‐1,3,4‐oxadiazole‐2(3H)‐thione (L), has been used to create the novel complexes tetranitratobis{μ‐5‐(pyridin‐4‐yl)‐3‐[2‐(pyridin‐4‐yl)ethyl]‐1,3,4‐oxadiazole‐2(3H)‐thione}zinc(II), [Zn₂(NO₃)₄(C₁₄H₁₂N₄OS)₂], (I), and catena‐poly[[[dinitratocopper(II)]‐bis{μ‐5‐(pyridin‐4‐yl)‐3‐[2‐(pyridin‐4‐yl)ethyl]‐1,3,4‐oxadiazole‐2(3H)‐thione}] nitrate acetonitrile sesquisolvate dichloromethane sesquisolvate], {[Cu(NO₃)(C₁₄H₁₂N₄OS)₂]NO₃·1.5CH₃CN·1.5CH₂Cl₂}_n, (II). Compound (I) presents a distorted rectangular centrosymmetric Zn₂L₂ ring (dimensions 9.56 × 7.06 Å), where each Zn^II centre lies in a {ZnN₂O₄} coordination environment. These binuclear zinc metallocycles are linked into a two‐dimensional network through nonclassical C—H...O hydrogen bonds. The resulting sheets lie parallel to the ac plane. Compound (II), which crystallizes as a nonmerohedral twin, is a coordination polymer with double chains of Cu^II centres linked by bridging L ligands, propagating parallel to the crystallographic a axis. The Cu^II centres adopt a distorted square‐pyramidal CuN₄O coordination environment with apical O atoms. The chains in (II) are interlinked via two kinds of π–π stacking interactions along [01]. In addition, the structure of (II) contains channels parallel to the crystallographic a direction. The guest components in these channels consist of dichloromethane and acetonitrile solvent molecules and uncoordinated nitrate anions.     

Facile Synthesis of N‐(Benzyl‐1H‐1,2,3‐Triazol‐5‐yl) Methyl)‐4‐(6‐Methoxybenzo [d] Thiazol‐2‐yl)‐2‐Nitrobenzamides via Click Chemistry

A series of novel N‐((l‐benzyl‐lH‐l,2,3‐triazol‐5‐yl) methyl)‐4‐(6‐methoxy benzo[d ]thiazol‐2‐yl)‐2‐nitrobenzamide derivatives were prepared from 4‐(6‐methoxybenzo[d ]thiazol‐2‐yl)‐2‐nitro‐N‐(prop‐2‐ynyl) benzamide with benzyl azides by using click reaction (copper‐catalyzed Huisgen 1,3‐dipolar cycloaddition reaction) in the presence of CuSO₄.5H₂O and sodium ascaorbate. All the newly synthesized compounds were evaluated further in vitro antimicrobial activity against Gram‐positive bacteria (Staphylococcus aureus and Bacillus subtillis ), Gram‐negative bacteria (Echerichia coli and Pseudomonas aeuroginosa ), and fungi (Aspergillus niger and Aspergillusfumigatus ) strains. The new compounds were characterized based on spectroscopic evidence. Among them compounds 10a , 10h , and 10i were showed promising activity when compared with standard drugs Ciprofloxacin and Miconazole.     

A Facile and Simple Synthesis of Novel 2‐(substituted)‐5‐(1‐methyl‐1H‐indazol‐3‐yl)‐Oxazole Derivatives

Novel 2‐(substituted)‐5‐(1‐methyl‐1H‐indazol‐3‐yl)‐oxazoles ( 13 ) were synthesized in moderate yields, from 1‐methyl‐1H‐Indazole 3‐carboxylic acid ( 1 ), by converting it into a variety of amides ( 12 ) and further its heterocyclization. The structures of all the compounds have been elucidated on the basis of IR, ¹H‐NMR, and HRMS.