1208259-07-7Relevant academic research and scientific papers
Nickel-Catalyzed [4 + 2] Annulation of Nitriles and Benzylamines by C-H/N-H Activation
Sikari, Rina,Chakraborty, Gargi,Guin, Amit Kumar,Paul, Nanda D.
, p. 279 - 290 (2021)
Nickel-catalyzed [4 + 2] annulation of benzylamines and nitriles via C-H/N-H bond activation, providing straightforward atom-economic access to a wide variety of multisubstituted quinazolines, is reported. Mechanistic investigation revealed that the in situ formed amidines from the coupling of benzylamines and nitriles direct the nickel catalyst to activate the ortho-C-H bond of the phenyl ring of the benzylamine.
Mixed crystalline phases and catalytic performance of OMS-2 based nanocomposites for one-pot synthesis of quinazolines with O2 as an oxidant
Yao, Nan,Bi, Xiuru,Zhang, Liping,Tao, Luyao,Zhao, Peiqing,Meng, Xu,Liu, Xiang
, (2021)
In this work, a series of sodium phosphotungstate modified manganese oxide octahedral molecular sieve (OMS-2) catalysts ([PW]-OMS-2) were developed, and their catalytic activities were investigated by one-pot synthesis of quinazolines from benzyl alcohol and 2-aminobenzylamine with O2 as green oxidant in dimethyl carbonate (DMC). TEM, XRD and EDS confirmed that sodium phosphotungstate decomposed into phosphotungstic acid and sodium tungstate in the doping process. Meanwhile, phosphotungstic acid attached and located at the surface of OMS-2 and W ions were successfully doped into the OMS-2 framework. For comparison, phosphotungstic acid/OMS-2 was prepared by simple wet impregnation method. The [PW]-OMS-2 is the most highly selective and effective over than phosphotungstic acid/OMS-2 and OMS-2 itself in the one-pot synthesis of quinazolines. It may be due to the synergetic effect of phosphotungstic acid and OMS-2, and successfully doping W into OMS-2 frameworks. Hence, this work provides a new environmentally-friendly and heterogeneous OMS-2 based nanocomposites and it may be put into practice to synthesize heterocyclic compounds.
Quinazoline-Directed C–H Bond Functionalization Catalyzed by Ruthenium(II) Carboxylate – Construction of Polyconjugated Aryl-Heteroaryl Systems
?tefane, Bogdan,Brodnik ?ugelj, Helena,Gro?elj, Uro?,Kuzman, Petra,Svete, Jurij,Po?gan, Franc
, p. 1855 - 1864 (2017)
A series of coupling products have been prepared by a ruthenium(II)-catalyzed direct ortho-C–H arylation of 2-(aryl/heteroaryl)-substituted quinazolines with (hetero)aryl bromides. Tri(hetero)aryl-substituted alkenes were also prepared by olefinic C–H activation of 2-(2-arylvinyl)quinazoline derivatives. High conversions and selectivities were achieved by choosing the appropriate ruthenium(II) carboxylate catalyst system, solvent, and reaction temperature. The possibility of a C(sp3)–H functionalization by applying an arylation/reduction reaction sequence was also demonstrated.
Synthesis of quinazolines from 2-aminobenzylamines with benzylamines and N-substituted benzylamines under transition metal-free conditions
Tiwari, Abhishek R.,Bhanage, Bhalchandra M.
, p. 10567 - 10571 (2016)
This work reports the synthesis of quinazolines from 2-aminobenzylamines with N-substituted benzylamines in the presence of molecular iodine. The developed methodology works smoothly under transition-metal free, additive free and solvent free conditions. The use of O2 as a green oxidant makes it a greatly economical, green and sustainable protocol. Moreover, no aqueous work up is required thereby enhancing the efficiency. A series of quinazoline derivatives were synthesized successfully in good to excellent yields.
BTP-Rh@g-C3N4 as an efficient recyclable catalyst for dehydrogenation and borrowing hydrogen reactions
Luo, Lan,Liu, Hongqiang,Zeng, Wei,Hu, Wenkang,Wang, Dawei
, (2021/11/16)
Highly active catalysts play an important role in modern catalysis. A novel and efficient ligand benzotriazole-pyrimidine (BTP) and the corresponding rhodium composite on C3N4 were successfully synthesized. The resulting rhodium composite was fully characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), thermogravimetric analysis (TGA), and x-ray photoelectron spectroscopy (XPS). The obtained composite exhibited good catalytic activity and good recovery performance in the synthesis of quinoxaline from 2-aminobenzyl alcohol and benzonitrile, and more than 20 quinoxalines were obtained in good yields. Additionally, it also showed that rhodium composite could achieved good catalytic performance in the synthesis of functionalized ketone through borrowing hydrogen strategy.
Type I ‘Lighted Metal-free’ Photosensitizing Assemblies of Phenazine for Aerobic Oxidative Transformations
Kaur, Lovjot,Kaur, Harpreet,Kumar, Manoj,Bhalla, Vandana
supporting information, p. 4179 - 4186 (2021/11/23)
Highly photostable supramolecular photosensitizing ‘lighted metal-free’ assemblies of DPZ-Th have been developed which show strong absorption in the visible region and excellent electron transportation potential from donor to acceptor units. The as-prepar
Possible competitive modes of decarboxylation in the annulation reactions ofortho-substituted anilines and arylglyoxylates
Laha, Joydev K.,Panday, Surabhi,Tomar, Monika,Patel, Ketul V.
, p. 845 - 853 (2021/02/09)
Annulation reactions ofortho-substituted anilines and arylglyoxylates in the presence of K2S2O8at 80 °C under metal-free neutral conditions have been investigated, which extended a platform for the tandem synthesis of nitrogen heterocycles. While arylglyoxylic acids are known to undergo decarboxylation to form an acyl radical in the presence of K2S2O8and used in the Minisci acylation of electron-deficient (hetero)aromatics, their reactions with electron-richortho-substituted anilines to form nitrogen heterocycles have recently been studied. Depending upon the experimental conditions used in the reactions, the mechanism of the formation of heterocycles involving reactions of an acyl radical or aryl iminocarboxylic acids has been postulated. Given the subtle understanding of the mechanisms of annulation reactions of 2-substituted anilines and arylglyoxylates in the presence of K2S2O8, an extensive mechanistic investigation was undertaken. In the current study, the various mechanistic pathways including the generation of acyl, imidoyl, aminal, and N,O-hemiketal radicals have been postulated based on different possible decarboxylation modes. Some of the proposed intermediates are supported based on the available analytical data. The protocol uses a single, inexpensive reagent K2S2O8, which offers not only transition-metal-free conditions but also serves as the reagent for the key decarboxylation step. Taken together, this study complements the current development of the annulation reactions of 2-substituted anilines and arylglyoxylates in terms of synthesis and mechanistic understanding.
Zinc Stabilized Azo-anion Radical in Dehydrogenative Synthesis of N-Heterocycles. An Exclusively Ligand Centered Redox Controlled Approach
Das, Siuli,Mondal, Rakesh,Chakraborty, Gargi,Guin, Amit Kumar,Das, Abhishek,Paul, Nanda D.
, p. 7498 - 7512 (2021/06/30)
Herein we report an exclusively ligand-centered redox controlled approach for the dehydrogenation of a variety of N-heterocycles using a Zn(II)-stabilized azo-anion radical complex as the catalyst. A simple, easy-to-prepare, and bench-stable Zn(II)-complex (1b) featuring the tridentate arylazo pincer, 2-((4-chlorophenyl)diazenyl)-1,10-phenanthroline, in the presence of zinc-dust, undergoes reduction to form the azo-anion radical species [1b]- which efficiently dehydrogenates various saturated N-heterocycles such as 1,2,3,4-tetrahydro-2-methylquinoline, 1,2,3,4-tetrahydro-isoquinoline, indoline, 2-phenyl-2,3-dihydro-1H-benzoimidazole, 2,3-dihydro-2-phenylquinazolin-4(1H)-one, and 1,2,3,4-tetrahydro-2-phenylquinazolines, among others, under air. The catalyst has further been found to be compatible with the cascade synthesis of these N-heterocycles via dehydrogenative coupling of alcohols with other suitable coupling partners under air. Mechanistic investigation reveals that the dehydrogenation reactions proceed via a one-electron hydrogen atom transfer (HAT) pathway where the zinc-stabilized azo-anion radical ligand abstracts the hydrogen atom from the organic substrate(s), and the whole catalytic cycle proceeds via the exclusive involvement of the ligand-centered redox events where the zinc acts only as the template.
Niacin as a Potent Organocatalyst towards the Synthesis of Quinazolines Using Nitriles as C–N Source
Gujjarappa, Raghuram,Vodnala, Nagaraju,Reddy, Velma Ganga,Malakar, Chandi C.
, p. 803 - 814 (2020/02/18)
An efficient and cost-effective Vitamin-B3-catalyzed protocol towards the synthesis of diversely substituted quinazolines is illustrated using 2-aminobenzylamines and nitriles as substrates. An organocatalytic transformation has been investigat
"Metal-Free" Nanoassemblies of AIEE-ICT-Active Pyrazine Derivative: Efficient Photoredox System for the Synthesis of Benzimidazoles
Dadwal, Shruti,Kumar, Manoj,Bhalla, Vandana
, p. 13906 - 13919 (2020/11/20)
Supramolecular nanoassemblies of an AIEE-ICT-active pyrazine derivative (TETPY) having strong absorption in the visible region and excellent transportability have been utilized as an efficient photoredox catalytic system for the synthesis of a variety of benzimidazoles having electron-withdrawing/electron-releasing/aliphatic groups under "metal-free"conditions. The reaction protocol involves the successful harvesting of visible light by TETPY assemblies to catalyze the coupling of o-phenylenediamine/substituted diamines and substituted aromatic/heterocyclic/aliphatic aldehydes under aerial conditions using mixed aqueous media as the reaction solvent. TETPY assemblies could activate aerial oxygen to generate superoxide for completing the vital proton abstraction step without the need for any external metal/base/oxidant. Moreover, all the products are purified by recrystallization from organic solvents. The TETPY assemblies also exhibited high efficiency in catalyzing the synthesis of 2-substituted benzothiazoles and quinazolines in excellent yields.
