628-13-7Relevant articles and documents
Enzyme-like Supramolecular Iridium Catalysis Enabling C?H Bond Borylation of Pyridines with meta-Selectivity
Al-Shehimy, Shaymaa,Gramage-Doria, Rafael,Roisnel, Thierry,Trouvé, Jonathan,Zardi, Paolo
supporting information, p. 18006 - 18013 (2021/05/07)
The use of secondary interactions between substrates and catalysts is a promising strategy to discover selective transition metal catalysts for atom-economy C?H bond functionalization. The most powerful catalysts are found via trial-and-error screening due to the low association constants between the substrate and the catalyst in which small stereo-electronic modifications within them can lead to very different reactivities. To circumvent these limitations and to increase the level of reactivity prediction in these important reactions, we report herein a supramolecular catalyst harnessing Zn???N interactions that binds to pyridine-like substrates as tight as it can be found in some enzymes. The distance and spatial geometry between the active site and the substrate binding site is ideal to target unprecedented meta-selective iridium-catalyzed C?H bond borylations with enzymatic Michaelis–Menten kinetics, besides unique substrate selectivity and dormant reactivity patterns.
Valorization of chitin derived N-acetyl-D-glucosamine into high valuable N-containing 3-acetamido-5-acetylfuran using pyridinium-based ionic liquids
Zang, Hongjun,Lou, Jing,Jiao, Shuolei,Li, Huanxin,Du, Yannan,Wang, Jiao
, (2021/02/26)
Chitin and its derivatives contain biologically fixed nitrogen elements, which can provide nitrogen sources for N-containing chemicals. Herein, a series of pyridinium-based ionic liquids were synthesized to directly catalyze the conversion of N-acetyl-D-glucosamine (NAG, the monomer of chitin) to 3-acetamido-5-acetylfuran (3A5AF). The yield of 3A5AF in 1-carboxymethyl pyridinium chloride ionic liquid reached 37.49%, without any additives. Using B2O3 and CaCl2 as additives, the optimum yield increased to 67.37% at 180 °C in 20 min. In addition, HPLC-MS analysis has been utilized to elucidate the reaction mechanism. This research on turning “waste” into “wealth” opens up new ways for the utilization of biomass waste, which not only reduces environmental pollution but also has potential economic value.
PhICl2is activated by chloride ions
Tania,Poynder, Tiffany B.,Kaur, Aishvaryadeep,Barwise, Lachlan,Houston, Sevan D.,Nair, Akshay J.,Clegg, Jack K.,Wilson, David J. D.,Dutton, Jason L.
supporting information, p. 11986 - 11991 (2021/09/06)
A study on the potential activating role of pyridine in the electrophilic chlorination of anisole by PhICl2has led to the discovery that soluble sources of chloride ions activate PhICl2in the reaction at catalytic loadings, greatly increasing the rate of chlorination. It is further shown that presence of chloride increases the rate of decomposition of PhICl2into PhI and Cl2. The specific mechanism by which chloride induces electrophilic chlorination and decomposition of PhICl2remains an open question.
Deaminative chlorination of aminoheterocycles
Cornella, Josep,Faber, Teresa,Gómez-Palomino, Alejandro,Ghiazza, Clément
, (2021/12/23)
Selective modification of heteroatom-containing aromatic structures is in high demand as it permits rapid evaluation of molecular complexity in advanced intermediates. Inspired by the selectivity of deaminases in nature, herein we present a simple methodology that enables the NH2 groups in aminoheterocycles to be conceived as masked modification handles. With the aid of a simple pyrylium reagent and a cheap chloride source, C(sp2)?NH2 can be converted into C(sp2)?Cl bonds. The method is characterized by its wide functional group tolerance and substrate scope, allowing the modification of >20 different classes of heteroaromatic motifs (five- and six-membered heterocycles), bearing numerous sensitive motifs. The facile conversion of NH2 into Cl in a late-stage fashion enables practitioners to apply Sandmeyer- and Vilsmeier-type transforms without the burden of explosive and unsafe diazonium salts, stoichiometric transition metals or highly oxidizing and unselective chlorinating agents. [Figure not available: see fulltext.]
Sterically Hindered 2,4,6-Tri- tert-butylpyridinium Salts as Single Hydrogen Bond Donors for Highly Stereoselective Glycosylation Reactions of Glycals
Ghosh, Titli,Mukherji, Ananya,Kancharla, Pavan K.
supporting information, p. 3490 - 3495 (2019/05/24)
We demonstrate here that the strained and bulky protonated 2,4,6-tri-tert-butylpyridine salts serve as efficient catalysts for highly stereoselective glycosylations of various glycals. Moreover, the mechanism of action involves an interesting single hydrogen bond mediated protonation of glycals and not via the generally conceived Br?nsted acid pathway. The counteranions also play a role in the outcome of the reaction.
Method for synthesizing 2, 3-dichloropyridine
-
Paragraph 0020 0022; 0024; 0026; 0028; 0029; 0030; 0031, (2018/04/02)
The invention discloses a method for synthesizing 2, 3-dichloropyridine (III). The method comprises that 1) pyridine (I) as a main starting raw material and chlorine undergo a full reaction in water or vapor as a reaction medium in the presence of a chlorination inducer to produce a pyridine chloride (II) as the next reaction raw material, and 2) the pyridine chloride (II) as a reaction raw material contacts with hydrogen and undergoes a catalytic hydrogenation reduction reaction in water or vapor as a reaction medium in the presence of an acid-binding agent and a catalyst to produce 2, 3-dichloropyridine (III) having purity of 99% or more, wherein the catalyst is a nanometer IrO2-ZnO-MnO2 composite catalyst. The reaction equation is shown in the description and n is 2-5. The method has the advantages of high reaction conversion rate, high selectivity, stable product quality, simple processes and low cost and solves the problem that the existing synthesis method produces 2, 3-dichloropyridine (III) having unstable quality and satisfying the quality standards after multiple rectification processes.
Ionic liquids as efficient pretreatment solvents for lignocellulosic biomass
Wang, Fu-Ling,Li, Shuang,Sun, Yi-Xin,Han, Hui-Ying,Zhang, Bi-Xian,Hu, Bao-Zhong,Gao, Yun-Fei,Hu, Xiao-Mei
, p. 47990 - 47998 (2017/10/31)
Ionic liquid (IL)-assisted pretreatment of lignocellulosic biomass has been extensively studied. Cellulose and hemicelluloses are rich resources of sugars for biofuels. Lignin is a valuable feedstock for aromatic-based platform chemicals. In this study, a series of ionic liquids (ILs) were prepared with one-step synthesis and were investigated for their activity to pretreat lignocelluloses. High yields of lignin (61.0% and 60.4%) were achieved through [Hpy]Cl and [Hmim]Cl pretreatment of poplar. Lignin yields of 51.7% and 50.3% were obtained with a [Hpy]Cl and [Hnmp]Cl pretreatment of bamboo. Improving enzymatic hydrolysis was observed from the regenerated poplar with [Hpy]Cl pretreatment and the regenerated bamboo with [Hmim]Cl pretreatment. The isolated fractions were characterized by FTIR (Fourier transform infrared) spectroscopy. SEM (Scanning electron microscopy) and XRD (X-ray diffractometry) were employed to examine the cellulose-rich materials. A 2D 1H-13C heteronuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectroscopy was employed to analyze lignin fraction. These ionic liquids were particularly effective to extract lignin from lignocelluloses to obtain cellulose-rich materials for biofuels.
A 2, 3 - dichloro pyridine synthesis method (by machine translation)
-
Paragraph 0019; 0021; 0023; 0025; 0026; 0027, (2017/11/08)
The invention discloses a 2, 3 - chlorinate (III) synthetic method, the steps of: 1) to pyridine (I) as the main starting material, water or steam is used as the reaction medium, in the presence of chlorinated derivative, pyridine react with chlorine to the full, (II) to obtain the pyridine chloride as a next step the reaction raw material; 2) to obtain the 1st step (II) of the pyridine chloride as the reaction raw material, water or steam is used as the reaction medium, in the acid, the presence of a catalyst, pyridine chloride (II) contact with hydrogen gas, by catalytic hydrogenation reduction reaction, to obtain the purity of 99% or more of the 2, 3 - chlorinate (III), the catalyst is nano IrO2 - ZnO - MnO2 Composite catalyst. The reaction equation is for:???: ???: C:Program Files gwssi CPC????? cases inventions 097cc1fe - cb01 - 4116 - 9 cd3 - cbef3e3f4998 new 100002 dest_path_image002.jpgWherein n=2 - 5. The reaction of the invention conversion and high selectivity, stability of the product quality, production operation is simple, low cost and the like, overcomes the obtained synthetic method for 2, 3 - chlorinate (III) of the instability and must be approved by the numerous rectification can make the 2, 3 - chlorinate (III) the quality of the deficiency of the standard. (by machine translation)
Synthesis, steady-state, and femtosecond transient absorption studies of resorcinol bound ruthenium(II)- and osmium(II)-polypyridyl Complexes on nano-TiO2 surface in water
Banerjee, Tanmay,Kaniyankandy, Sreejith,Das, Amitava,Ghosh, Hirendra Nath
, p. 5366 - 5377 (2013/06/26)
The synthesis of two new ruthenium(II)- and osmium(II)-polypyridyl complexes 3 and 4, respectively, with resorcinol as the enediol anchoring moiety, is described. Steady-state photochemical and electrochemical studies of the two sensitizer dyes confirm strong binding of the dyes to TiO2 in water. Femtosecond transient absorption studies have been carried out on the dye-TiO2 systems in water to reveal 120 fs and 1.5 ps electron injection times along with 30% slower back electron transfer time for the ruthenium complex 3. However, the corresponding osmium complex 4 shows strikingly different behavior for which only a 120 fs ultrafast injection is observed. Most remarkably, the back electron transfer is faster as compared to the corresponding catechol analogue of the dye. The origin and the consequences of such profound effects on the ultrafast interfacial dynamics are discussed. This Article on the electron transfer dynamics of the aforesaid systems reinforces the possibility of resorcinol being explored and developed as an extremely efficient binding moiety for use in dye-sensitized solar cells.
Preparation, characterization and application of ionic liquid sulfonic acid functionalized pyridinium chloride as an efficient catalyst for the solvent-free synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[a]-xanthen-11-ones
Moosavi-Zare, Ahmad Reza,Zolfigol, Mohammad Ali,Zarei, Mahmoud,Zare, Abdolkarim,Khakyzadeh, Vahid
, p. 63 - 69 (2013/09/12)
In this work, novel ionic liquid namely sulfonic acid functionalized pyridinium chloride {[Pyridine-SO3H]Cl} is synthesized, and characterized by studying its IR, UV, 1H and 13C NMR as well as mass spectra. This ionic liquid is used as an efficient, homogeneous and reusable catalyst for the solvent-free synthesis of 12-aryl-8,9,10,12- tetrahydrobenzo[a]-xanthen-11-ones by the one-pot multi-component condensation of 2-naphthol with arylaldehydes and dimedone (5,5-dimethylcyclohexane-1,3- dione).
