نتایج جستجو برای: imidazoles multicomponent nmr

تعداد نتایج: 72088  

2013
Adel A. Marzouk Avtandil H. Talybov Shaaban Kamel Mohamed

A simple highly versatile and efficient synthesis of 2,4,5-trisubstituted imidazoles is achieved by three component cyclocondensation of 1,2-dicarbonyl compounds, aldehydes and ammonium acetate as ammonia source in thermal solvent free condition using Brønsted acidic ionic liquid diethyl ammonium hydrogen phosphate as catalyst. The key advantages of this process are cost effectiveness of cataly...

2012
Adel A. Marzouk Vagif M. Abbasov Avtandil H. Talybov

Morpholinium hydrogen Sulphate as Brønsted acidic ionic liquid was used as an efficient and reusable catalyst for the onepot synthesis of 2,4,5-trisubstituted imidazoles that achieved by three component cyclocondensation of 1,2-dicarbonyl compound, aromatic or aliphatic aldehyde and ammonium acetate under thermal solvent-free conditions. The key advantages of this process are cost effectiveness...

Stable crystalline phosphorus ylides are obtained in excellent yields from the 1:1:1 addition reactionbetween hydantoins or thiohydantoins and dialkyl acetylenedicarboxylates in the presence oftriphenylphosphine. These phosphoranes undergo smooth intramolecular Wittig reaction followedby an electrocyclic ring opening to produce dialkyl (E)-2-(2,5-dihydro-5,5-diaryl-2-thioxo-1H-imidazol-4-yl)fum...

Because of the significant role in biological processes in living cells and the diverse types of physiological activities, heterocyclic compounds are in focus of intense investigations by academic, industry and applied-oriented chemists. Considerably, ascientific renaissance of heterocycles during the last decades is closely related to the development of multicomponent approaches to their s...

1999
Richard N. Butler Martin O. Cloonan John M. McMahon Luke A. Burke

Quaternisation of 3,5-diaryl-1,2,4-thiadiazoles with trimethylsilylmethyl triflate at 40 8C occurred at N-2. Separate desilylation of the salts resulted in a ring expansion to substituted 2H-1,3,5-thiadiazines 5. Heating of these with ethanolic sodium ethoxide caused sulfur extrusion and ring contraction to 2,4-disubstituted imidazoles 6. 3,4-Diaryl1,2,5-thiadiazoles were less reactive to alkyl...

2016
Roman V. Shchepin Danila A. Barskiy Aaron M. Coffey Thomas Theis Fan Shi Warren S. Warren Boyd M. Goodson Eduard Y. Chekmenev

15N nuclear spins of imidazole-15N2 were hyperpolarized using NMR signal amplification by reversible exchange in shield enables alignment transfer to heteronuclei (SABRE-SHEATH). A 15N NMR signal enhancement of ∼2000-fold at 9.4 T is reported using parahydrogen gas (∼50% para-) and ∼0.1 M imidazole-15N2 in methanol:aqueous buffer (∼1:1). Proton binding to a 15N site of imidazole occurs at physi...

2010
Mukesh C. Sharma Dharm V. Kohli Smita Sharma

Mukesh C. Sharma Dept. of Pharmaceutical Sciences, Dr.Hari Singh Gour University Sagar (M.P) 470003 India Department of Chemistry Yadhunath Mahavidyalya Bhind (M.P) 477001 India Email: [email protected] Abstract A new series of non peptide angiotensin (A-II) receptor antagonist has been prepared. This N-(biphenyl methyl) imidazoles e.g. Some new 4'-{5-amino2-[2-substituted-phenylamino)-ph...

Journal: :Angewandte Chemie 2005
Yoram Cohen Liat Avram Limor Frish

Intermolecular interactions in solution play an important role in molecular recognition, which lies at the heart of supramolecular and combinatorial chemistry. Diffusion NMR spectroscopy gives information over such interactions and has become the method of choice for simultaneously measuring diffusion coefficients of multicomponent systems. The diffusion coefficient reflects the effective size ...

Journal: :Antimicrobial agents and chemotherapy 2005
Ryan A Helmick Arin E Fletcher Anne M Gardner Christopher R Gessner Angela N Hvitved Michael C Gustin Paul R Gardner

Flavohemoglobins metabolize nitric oxide (NO) to nitrate and protect bacteria and fungi from NO-mediated damage, growth inhibition, and killing by NO-releasing immune cells. Antimicrobial imidazoles were tested for their ability to coordinate flavohemoglobin and inhibit its NO dioxygenase (NOD) function. Miconazole, econazole, clotrimazole, and ketoconazole inhibited the NOD activity of Escheri...

Journal: :Düzce Üniversitesi bilim ve teknoloji dergisi 2021

An efficient green approach for the synthesis of 9-heteroaryl-acridine-1,8-dione derivatives (3a-f) was accomplished via reactions dimedone (1) with various heteroaromatic aldehydes (2a-f) and ammonium acetate through one-pot multicomponent in water under mild conditions using ultrasound irradiation excellent yields. Of synthesized compounds, 3d-f were novel this process presents advantages hig...

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