1007580-21-3Relevant articles and documents
C[sbnd]H Bond activation of 2-isobutylthiazole at C5 position catalysed by Pd-N-heterocyclic carbene complexes
Bu?day, Nesrin,Khan, Siraj,Ya?ar, Sedat,?zdemir, ?smail
, (2021)
A highly efficient and effective protocol has been developed for the synthesis of C5-(hetero)arylated 2-isobutylthiazole derivatives. Four different palladium N-heterocyclic carbene (Pd-NHCs) complexes [Pd(μ-Cl)Cl(SIMes)]2 (2), (LCl2Pd-SIMes) (3: L = PPh3; 4: L = Py; 5: L = 3-CHO-Py) were synthesized and used for the first time as a catalysts in direct C-H arylation reaction of 2-isobutylthiazole at C5 position. Utilizations of these catalytic systems, the arylation of 2-isobutylthiazole with substituted (hetero)aryl bromides efficiently proceeded at low catalyst loading (1mol%) and without any additives such as PivOH under argon or aerobic conditions at 120 °C in a short time. Different substituted (hetero)aryl bromides, even some deactivated or highly sterically hindered (hetero)arylbromides, with a wide range of functional groups were successfully utilized under the optimum reaction conditions. In all cases, the C5 arylated 2-isobutylthiazoles were obtained in moderate to excellent yields.
The p: K a values of N-aryl imidazolinium salts, their higher homologues, and formamidinium salts in dimethyl sulfoxide
Cole, Marcus L.,Dunn, Michelle H.,Harper, Jason B.,Konstandaras, Nicholas,Luis, Ena T.
supporting information, p. 1910 - 1917 (2020/03/23)
A series of imidazolinium salts, their six-, seven- A nd eight-membered homologues, and the related formamidinium salts were prepared, and their pKa values were determined in DMSO at 25 °C using the bracketing indicator method. The effect of each type of structural variation on the acidity of each salt was considered, particularly noting the importance of ring size and the effect of the steric and electronic nature of the N-aryl substituents. The effect of a cyclic structure was also probed through comparing the cyclic systems with the corresponding formamidinium salts, noting the importance of conformational flexibility in the latter cases. Along with allowing choice of appropriate bases for deprotonation of these species, it is anticipated that the data presented will aid in the understanding of the nucleophilicity, and potentially catalytic efficacy, of the corresponding carbenes.
Anionic ring-opening homo- and copolymerization of lactams by latent, protected N-heterocyclic carbenes for the preparation of PA 12 and PA 6/12
Naumann, Stefan,Schmidt, Friedrich Georg,Speiser, Maria,Boehl, Margit,Epple, Stefan,Bonten, Christian,Buchmeiser, Michael R.
, p. 8426 - 8433 (2013/12/04)
Laurolactam (LL) is polymerized in the bulk using strongly basic N-heterocyclic carbenes (NHCs) as initiators at temperatures of 180-200 C to prepare the corresponding polyamide (PA 12). In-situ rheology of the polymerization progress reveals that an anionic mechanism is active, which is supported by the strong dependence of initiator activity on the basicity of the NHCs. GPC data and kinetic investigations show the process to be moderately controlled and fast, allowing high or quantitative yields in short polymerization times. Fifteen different NHC-CO2-adducts and NHC-metal complexes were used as thermally labile but room temperature stable NHC-precursors. Depending on the ring size and N-substituent, some of these protected NHCs allow forming a mixture of monomer and NHC-precursor that is suitable for long-term storage and readily polymerizable by simple heating. All polymerizations are executed without activator or other additives and thus represent a true one-component system for the production of PA 12. Finally, LL is copolymerized with ε-caprolactam (ε-CLA). It is found that a copolymer with a considerable gradient is formed, with ε-CLA being incorporated preferentially at the onset of the polymerization.
Synthesis of 1,2 diamines under environmentally benign conditions: application for the preparation of imidazolidiniums
Roche, Stéphane P.,Teyssot, Marie-Laure,Gautier, Arnaud
supporting information; scheme or table, p. 1265 - 1268 (2010/04/29)
An environmentally friendly and economically attractive access to unsymmetrical and symmetrical 1,2-diamines has been developed. Chemoselective N-monoalkylation in water and alcoholic solvents was demonstrated. This method represents a simple and scalable preparation (2-3 steps) of symmetrical and unsymmetrical imidazolidinium salts, precursors of N-Heterocyclic Carbenes.
PREPARATION OF SATURATED IMIDAZOLINIUM SALTS AND RELATED COMPOUNDS
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Page/Page column 13; 17-19, (2009/06/27)
Methods for the preparation of saturated imidazolinium salts and related compounds that comprises reaction of formamidines with compounds such as dihaioethane and an optional base are disclosed. Alternatively, the imidazoünium salts and related compounds can be prepared in a one-step process without purification of the formamidine reactant. These methods make it possible to obtain numerous imidazolinium salts and related compounds under solvent-free reaction conditions and in excellent yields.
