Synthesis of Some New Triphenylphosphanylidenes,Alkylphosphonates, and Heterocycles of Pyrazole Derivatives and Their Antimicrobial Activity

Abstract

The reaction of 5(4H)-pyrazolone with phosphorus ylides afforded new triphenylphosphanylidene alkanone derivatives. Moreover, its benzylidene derivative reacted with Wittig–Horner reagents to give the corresponding dialkoxyphosphoryl, alkyl phosphonate, and heterocyclic products. Treatment of pyrazole-4-carbaldehyde with Wittig–Horner reagents and trialkyl phosphites gave the respective alkyl phosphonate adducts. Mechanisms accounting for the formation of the new products are discussed. The biological activity of some of the newly synthesized compounds was also examined.     

Synthesis of Thermally Stable Energetic 1,2,3‐Triazole Derivatives

Various thermally stable energetic polynitro‐aryl‐1,2,3‐triazoles have been synthesized through Cu‐catalyzed [3+2] cycloaddition reactions between their corresponding azides and alkynes, followed by nitration. These compounds were characterized by analytical and spectroscopic methods and the solid‐state structures of most of these compounds have been determined by using X‐ray diffraction techniques. Most of the polynitro‐bearing triazole derivatives decomposed within the range 142–319 °C and their heats of formation and crystal densities were determined from computational studies. By using the Kamlet–Jacobs empirical relation, their detonation velocities and pressures were calculated from their heats of formation and crystal densities. Most of these newly synthesized compounds exhibited high positive heats of formation, good thermal stabilities, reasonable densities, and acceptable detonation properties that were comparable to those of TNT.     

Heterocyclic Synthesis with Enamines: Convenient Syntheses of Polyfunctionally Substituted Pyrazole,Pyridine, Pyrimidine and Pyrazolo[3,4-d]pyrimrdine Derivatives

Facile syntheses of pyrazole, pyridine, pyrimidine and pyrazolo[3,4-d]pyrimidine derivatives have been achieved by the reaction of β-enamino nitrile 2a with hydrazines, phenyl isothiocyanate, thiourea and active methylene reagents. The β-enamino ketone 2e with the same reagents affords 3,5-dimethyl heterocyclic ring systems.     

Facile Route for the Synthesis of Pyridazine Derivatives: Unexpected Pathway to Benzothiazole,Benzimidazole, and Triazole Derivatives

4‐Amino‐5‐arylmethylidene‐3‐phenyl‐pyridazin‐6‐ones 7 have been synthesized and reacted with selected nucleophile reagents such as phenyl hydrazine, semicarbazide, semithiocarbazide, cyanoacetohydrazide, 2‐aminothiophenol, and 2‐phenylenediamine in ethanol triethyl‐amine solution. An unexpected 1‐phenyl‐3‐arylaziridene 10, 3‐aryl‐5‐oxo(thio)‐1,2,4‐triazole 21, 4‐amino‐3‐aryl‐6‐hydroxy‐pridazine 27, 2‐arylbenzothiazole 30a–c, and 2‐arylbenzimidazole 30d–f have been obtained, respectively. Also, 2‐aminothiophenol and 2‐phenylenediamine were reacted with N‐phenylmethylidene‐2‐cyanoacetohydrazide 2, affording the new 1,4‐benzodiazepine derivatives 35.     

Synthetic and Biological Studies on New Urea and Triazole Containing Cystobactamid Derivatives

Cystobactamids belong to the group of arene-based oligoamides that effectively inhibit bacterial type IIa topoisomerases. Cystobactamid 861-2 is the most active member of these antibiotics. Most amide bonds present in the cystobactamids link benzoic acids with anilines and it was found that some of these amide bonds undergo chemical and enzymatic hydrolysis, especially the one linking ring C with ring D. This work reports on the chemical synthesis and biological evaluation of thirteen new cystobactamids that still contain the methoxyaspartate hinge. However, we exchanged selected amide bonds either by the urea or the triazole groups and modified ring A in the latter case. While hydrolytic stability could be improved with these structural substitutes, the high antibacterial potency of cystobactamid 861-2 could only be preserved in selected cases. This includes derivatives, in which the urea group is positioned between rings A and B and where the triazole is found between rings C and D.     

Synthesis and Antimicrobial Activity of Some Novel Hydrazide,Pyrazole, Triazine,Isoxazole, and Pyrimidine Derivatives

In continuation of our efforts to find a new class of antimicrobial agents, a series of pyrazole, 1,2,4‐triazine, isoxazole, pyrimidine, and other related products containing a hydrazide moiety were prepared via the reaction of 2‐cyano‐N‐((2‐methoxynaphthalen‐1‐yl)methylene) acetohydrazide ( 1 ) with appropriate chemical reagents. These compounds were evaluated for their antimicrobial activities, and also their minimum inhibitory concentration against most of test organisms was performed. Among the tested compounds 4 , 5 , 6 , and 16 displayed excellent antimicrobial activity. All the synthesized products were confirmed by elemental analysis, IR, ¹H‐NMR, ¹³C‐NMR, and mass spectral data.     

Synthesis,Reactions and Antimicrobial Activity of Some New Indolyl‐1,3,4‐Oxadiazole,Triazole and Pyrazole Derivatives

Indole‐3‐carboxylic acid hydrazide 3 was prepared and was treated with aromatic aldehydes in ethanol to give the corresponding hydrazone derivatives 4–7 in good yields. The indole carbohydrazide was incorporated into the 3‐indolyloxadiazoles 8–11 and 18 , 3‐indolyltriazoles 13–17 and 35 , 3‐indolylpyrazole derivatives 19–23 and carbamate derivatives 26–27 . Furthermore, interaction of the carboazide 24 with hydrazine hydrate in refluxing toluene afforded the corresponding semicarbazide derivative 30 . The thiadiazine derivative 34 was also prepared. Some of these compounds were screened in vitro for their antibacterial and antifungal activity.     

Synthesis,Crystal Structures,Fluorescence and Xanthine Oxidase Inhibitory of Sulfur-Containing Pyrazole Derivatives Incorporated with Oxadiazole and Triazole

Some sulfur-containing pyrazole derivatives incorporated with 1,3,4-oxadiazole and 1,2,4-triazole were designed and synthesized. All the compounds were fully characterized by IR, ¹H NMR, ¹³C NMR and elemental analyses. Two crystal structures were determined by single crystal X-ray diffraction analyses. The fluorescence properties were investigated in DMSO solution. In addition, the in vitro xanthine oxidase (XO) inhibitory activity were evaluated, and the results showed that one compound displayed moderate XO inhibitory activity.     

Synthesis and Herbicidal Activity of 1,2,4‐Triazole Derivatives Containing a Pyrazole Moiety

A series of triazole derivatives containing a pyrazole moiety were synthesized and characterized by ¹H NMR, ¹³C NMR, and HRMS. The herbicidal activities of these compounds were tested against lettuce and bentgrass. Most of the tested compounds were moderately herbicidal activity against lettuce and bentgrass. Among them, compounds 6f and 6g had the highest herbicidal activity (80% inhibitory) against lettuce and bentgrass.     

Synthesis,Antioxidant, and Antileishmanial Activities of New Bis-N-amino Triazole Derivatives

Russian Journal of General Chemistry - Synthesis of new bis-N-imino triazole derivatives containing oxadiazole 2, its Mannich base 3, and the S-alkyl group 4 is presented. Bis-N-iminotriazole 2 is...     

Synthesis of New Macrocyclic Schiff Bases Containing Pyrazole and Triazole as Subcyclic Units

The novel macrocyclic Schiff bases upon which were fused triazole and pyrazole units and containing N, O and S inside the macrocyclic ring as donor atoms were synthesized by condensation of appropriate bis(4‐amino‐1,2,4‐triazole‐3‐yl‐sulfanyl)alkanes 2a , 2b , 2c , 2d , 2e , 2f , 2g , 2h , 2i , 2j , 2k , 2l , 2m , 2n , 2o , 2p , 2q , 2r and pyrazoledialdehyde 3 in refluxing glacial acetic acid. The structural identities of these compounds were confirmed on the basis of spectrum.     

Synthesis of New 1,3,4‐Oxadiazol,Thiadiazole, 1,2,4‐Triazole,and Arylidene Hydrazide Derivatives of 4‐Oxo‐1,4‐dihydroquinoline with Antimicrobial Evaluation

A series of substituted 1,3,4‐oxadiazole, 1,2,4‐triazole, and 1,3,4‐thiadiazole derivatives of the substituted 3‐carboethoxy‐1,4‐dihydro‐4‐oxoquinoline have been synthesized through the reaction of the key intermediate thiosemicarbazide derivatives with different reagents. N′‐Arylidene‐4‐oxo‐1,4‐dihydroquinoline‐3‐carbohydrazides were also synthesized through the condensation reaction of the corresponding hydrazides with the appropriate aldehydes. Antimicrobial activity of some of the synthesized compounds was evaluated.     

Synthesis,Characterization, and Cytotoxic Evaluation of New Triazole Derivatives of Osthol

Russian Journal of Organic Chemistry - Osthol [7-methoxy-8-(3-methylbut-2-en-1-yl)chromen-2-one] isolated from Prangos pabularia was used as a starting material for the synthesis of its various...     

A New Route for the Synthesis of N-Substituted Diketopiperazine Derivatives

Eight N-substituted diketopiperazines (DKPs) were synthesized by solid-phase protocols. The introduction of iminodiacetic acid (Ida) and followed another α-amino acid residue as the precursor of DKP framework made the present synthesis to be very facile and efficient.     

吡唑类化合物的合成研究进展

吡唑类化合物是一类重要的药物合成中间体,在抗肿瘤、抗病毒、抗抑郁等领域发挥着重要作用。本文综述了吡唑类衍生物的合成方法,包括1,3-亲电化合物与肼类的环化、1,3-偶极体系的环加成等。     

吡唑衍生物的合成及生物活性

以５－吡唑甲酰肼（７，８）为原料合成了４类共３０种新化合物，这些化合物的结构均经＾１Ｈ ＮＭＲ，元素分析证实，部分化合物还经过了ＭＳ、ＩＲ确证，对大部分化合物做了生物活性测试，结果表明均具有一定的杀菌和除草活性。     

Green Synthesis of Pyrazole and Oxazole Derivatives

New intermediate 3‐methyl‐5‐oxopyrazol propanenitrile was synthesized by one pot three component reactions using ethyl cyanoacetate, hydrazine hydrate, and ethyl acetoacetate and was used for the synthesis of new oxazole and pyrazole derivatives. All reactions were carried out using eco‐friendly solvents and without catalyst.     

Synthesis,Characterization and Antibacterial Activity of New 5-Aryl Pyrazole Oxime Ester Derivatives

Eleven new 1-{5-[4-（benzyloxy）phenyl]-3-methyl-4,5-dihydropyrazol-l-yl} oxime ester dcrivatives were synthesized and characterized by elemental analysis, HRMS, ^1H NMR data. All the compounds were screened for their antibacterial potential in vitro against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The results indicate that compounds 8c and 8f possess potent activity with the minimum inhibitory concentrations（MIC） of 1.562--3.125 ug/mL against all the four bacteria. Compounds 8c, 8e and 8f show moderate inhibition against the DNA gyrase（IC50=1.9--2.5 ug/mL）. On the basis of the biological activities, structure-activity relationship was discussed.     

Benzimidazole Annulated New Heterocyclic Compounds: Synthesis of New Polycyclic Pyrazole Derivatives

Several ( 3 ) new benzimidazole based polycyclic compounds of potential pharmaceutical interest have been prepared starting from 2‐benzimidazolelyl (1,3‐dioxo‐2‐indenylidene) acetonitrile. Unhypothesized, the C≡N function of the plausible intermediates was released as HCN rather than a classical nucleophilic addition when treated with bidentate reagents such as hydrazines, 5‐amino‐1H‐1,2,4‐triazole, 5‐amino‐4‐cyano‐1H‐pyrazole and 2‐aminobenzimidazole. When compound 3 reacted with active acetonitrile derivatives it afforded new polyfunctional pyridines via elimination of HCN in addition to, new pyrimidine, pyrazine and azepine derivatives.     

An Efficient Synthesis of Some New Isolated and Fused Triazole Derivatives

A facile and efficient route to 5‐hydrazinyl‐3‐phenyl‐3H‐[1,2,4]triazole 2 from the reaction of triazol‐3‐one 1 and hydrazine hydrate is described. In addition, the formation of isolated and fused triazole derivatives was prepared via reaction of 2 with some selected electrophilic reagents in basic medium.