6931-28-8Relevant academic research and scientific papers
2-hydroxyethylammonium formate ionic liquid grafted magnetic nanoparticle as a novel heterogeneous catalyst for the synthesis of substituted imidazoles
Rajabzadeh, Maryam,Eshghi, Hossein,Khalifeh, Reza,Bakavoli, Mehdi
, (2018)
Catalytic one-pot condensation of benzil, aldehyde and ammonium acetate have been successfully carried out using 2-hydroxyethylammonium formate (HEAF) grafted on a magnetic nanoparticles as a new heterogeneous catalyst. The as-prepared catalyst was charac
NiO nanocomposites/rGO as a heterogeneous catalyst for imidazole scaffolds with applications in inhibiting the DNA binding activity
Kumar, Gyanendra,Kumar, Manish,Masram, Dhanraj T.,Mogha, Navin Kumar,Subodh
supporting information, p. 1963 - 1974 (2020/02/20)
Herein, we report a facile approach to synthesize a new highly versatile heterogeneous catalyst by spontaneous aerial oxidation based on nickel oxide nanocomposites immobilized on surface-functionalized reduced graphene oxide sheets. NiO nanocomposite/red
Importance of monodentate mono-ligand designs in developing N-stabilized Pd catalysts for efficient ambient temperature C[sbnd]C coupling: Donor strengths and steric features
Eseola, Abiodun Omokehinde,G?rls, Helmar,Plass, Winfried
, (2019/05/17)
Unfriendly temperature profiles and costs of carbon coupling catalysis, which pose challenge to both synthetic organic chemists as well as industrial applicability, motivated our design of new monodentate N-donors as support ligands for the purpose of constructing ambient temperature precatalysts that are molecularly close to the hypothetical active forms. Therefore, a series of sterically varied monodentate N-donor imidazoles (1–7) and oxazoles (8–9) have been synthesized and their N-donor strengths, which were estimated as pKas, are systematically varied from 0.9 to 8.5 by substituent variations. Eleven target mono-ligand complexes (1-PdCl2MeCN – 9-PdCl2MeCN, 6-PdCl2PhCN and 7-PdCl2PhCN) and six trans-bis-ligand complexes (12-PdCl2, 22-PdCl2, 32-PdCl2, 62-PdCl2, 12-Pd(OAc)2 and 22-Pd(OAc)2) were isolated and catalytically studied along with PdI2(PPh3)2. Results of coupling reactions, which were conducted both via in situ ‘Pd(II) salt + ligand’ approach and by use of the precatalysts, show that the mono-ligand precatalyst designs (1-PdCl2MeCN – 9-PdCl2MeCN, 6-PdCl2PhCN and 7-PdCl2PhCN) represent a true catalyst improvement initiative among the phosphine-free catalyst community; i.e. yields approaching 100% (TOF ≈ 2000) at 0.2 mol % catalyst loading, 45 °C and within 15 min. On the other hand, the complexes with trans-bis-ligand coordination were inactive at ambient temperatures. Therefore, it was concluded that coordinative saturation, which results from implementing two or more ligand equivalents or use of polydentate ligands on palladium, should be strongly discouraged. Such saturation necessitates the undesirable and avoidable high temperature necessities, long reflux durations and needlessly high catalyst loadings. Correlation between catalyst activity and donor strengths or steric properties were analysed leading to important conclusions. The catalyst design also supported coupling of activated aryl chlorides from 60 °C while Heck coupling activities were observed only at the early minutes of reactions.
Co(II) anchored glutaraldehyde crosslinked magnetic chitosan nanoparticles (MCS) for synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles
Singh, Harminder,Rajput, Jaspreet Kaur
, (2017/09/14)
A simple, highly efficient and green synthesis of 2,4,5-trisubsituted and 1,2,4,5-tetrasubstituted imidazoles was developed using a novel MCS-GT@Co(II) magnetically recoverable and recyclable catalyst under refluxing conditions with ethanol as a solvent. The catalyst was prepared by immobilization of chitosan onto Fe3O4 using glutaraldehyde as crosslinker followed by Co(II) ion immobilization via cobalt acetate. The catalyst was characterized using various techniques. For organic products determination, 1H NMR, 13C NMR and Fourier transform infrared spectroscopies were used. The reaction was also tried with individual components of the catalyst, but the synergistic effect of the components in the prepared catalyst showed the highest yield and shortest reaction time.
One-pot multi-component synthesis of N,N′-alkylidene bisamides and imidazoles using heteropoly-11-tungsto-1-vanadophosphoric acid supported on natural clay as catalyst: A green approach
Selvakumar, Karuppaiah,Shanmugaprabha, Thangamariyappan,Kumaresan, Murugan,Sami, Ponnusamy
, p. 2115 - 2126 (2017/10/31)
One-pot multi-component synthesis of N,N′-alkylidene bisamides, 2,4,5-trisubstituted imidazoles and 1,2,4,5-tetrasubstituted imidazoles in the presence of catalytic material heteropoly-11-tungsto-1-vanadophosphoric acid (HPV) supported on activated natura
Green synthesis of tri/tetrasubstituted 1H-imidazoles and 2,3-dihydroquinazolin-4(1H)-ones using nano aluminium nitride as solid source of ammonia
Hajjami, Maryam,Ghorbani-Choghamarani, Arash,Yousofvand, Zakieh,Norouzi, Masoomeh
, p. 1221 - 1228 (2015/10/06)
A simple, green and cost-effective protocol was achieved for the synthesis of tri/tetrasubstituted-1H-imidazoles and 2,3-dihydroquinazolin-4(1H)-ones using nano aluminium nitride. The reaction was carried out under catalyst-free conditions and the products were isolated in good to excellent yield. [Figure not available: see fulltext.]
Cobalt(II) catalyzed C(sp)-H bond functionalization of alkynes with phenyl hydrazines: Facile access to diaryl 1,2-diketones
Bharate, Jaideep B.,Abbat, Sheenu,Sharma, Rohit,Bharatam, Prasad V.,Vishwakarma, Ram A.,Bharate, Sandip B.
, p. 5235 - 5242 (2015/05/13)
A cobalt acetylacetonate catalyzed oxidative diketonation of alkynes via C(sp)-H bond functionalization has been described. The reaction involves a free-radical mechanism, wherein the phenyl radical formed from phenyl hydrazine couples with Co(ii) activated alkyne to produce 1,2-diketones. The reaction proceeds at room temperature in DMF with the use of Ag2O/air as the oxidizing system. The utility of the protocol for the synthesis of a series of imidazoles including a potent platelet aggregation inhibitor trifenagrel has been demonstrated.
Optical properties of pyrene and anthracene containing imidazoles: Experimental and theoretical investigations
Kumar, Dhirendra,Thomas, K.R. Justin
experimental part, p. 162 - 173 (2012/01/12)
A series of anthracene and pyrene containing imidazole derivatives have been synthesized and characterized by spectroscopy. Optical absorption and emission properties of the imidazole derivatives were examined in different solvents of varying polarity. Th
Spectroscopic study of 2-, 4- and 5-substituents on pKa values of imidazole heterocycles prone to intramolecular proton-electrons transfer
Eseola, Abiodun O.,Obi-Egbedi, Nelson O.
experimental part, p. 693 - 701 (2010/03/25)
New 2-(1H-imidazol-2-yl)phenols (L1Et-L8tBuPt) bearing a phenolic proton in the vicinity of the imidazole base were prepared and characterized. Experimental studies of the dependence of their protonation/deprotonation equilibrium on substituent identities
