- Environment-friendly and efficient synthesis of 2-aminobenzo-xazoles and 2-aminobenzothiazoles catalyzed by: Vitreoscilla hemoglobin incorporating a cobalt porphyrin cofactor
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In this study, an environment-friendly and efficient artificial Vitreoscilla hemoglobin (VHb) for the synthesis of 2-aminobenzoxazoles and 2-aminobenzothiazoles has been reported. We demonstrate an expression-based porphyrin substitution strategy to produce VHb containing cobalt porphyrin instead of native hemin, which can catalyze the oxidative cyclization of corresponding 2-aminobenzoxazoles and 2-aminobenthiazoles with up to 97% yield and 4850 catalytic turnovers in water under aerobic conditions. Hence, we provide a green and mild method for the synthesis of 2-aminobenzoxazoles and 2-aminobenzothiazoles. In addition, we indicate the value of porphyrin ligand substitution as a strategy to tune and enhance the catalytic properties of hemoproteins in non-natural reactions.
- Li, Fengxi,Li, Zhengqiang,Su, Jiali,Wang, Chunyu,Wang, Ciduo,Wang, Lei,Xu, Yaning,Zhao, Nan
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p. 8047 - 8052
(2021/11/01)
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- Switchable and Scalable Heteroarylation of Primary Amines with 2-Chlorobenzothiazoles under Transition-Metal-Free and Solvent-Free Conditions
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2-Aminobenzothiazoles comprise a valuable structural motif, which prevails in versatile natural products and biologically active compounds. Herein, a switchable and scalable C-N coupling protocol was developed for the synthesis of these compounds from 2-chlorobenzothiazoles and primary amines. Gratifyingly, this protocol was achieved under transition-metal-free and solvent-free conditions. Moreover, introducing an appropriate amount of NaH completely switched the selectivity from mono- toward di-heteroarylation, and further investigations provided a rationale for this new finding. Furthermore, gram-scale synthesis of representative products 3a and 4a was realized by applying operationally simple and glovebox-free procedures, which revealed the practical usefulness of this work. Finally, evaluation of the quantitative green metrics provided evidence that our protocol was superior over the literature ones in terms of green chemistry and sustainability.
- Cheng, Hua,Zhu, Yan-Qiu,Liu, Peng-Fei,Yang, Kai-Qiang,Yan, Jin,Sang, Wei,Tang, Xiao-Sheng,Zhang, Rui,Chen, Cheng
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p. 10288 - 10302
(2021/08/16)
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- Synthesis of Benz-Fused Azoles via C-Heteroatom Coupling Reactions Catalyzed by Cu(I) in the Presence of Glycosyltriazole Ligands
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Glycosyl triazoles are conveniently accessible and contain multiple metal-binding units that may assist in metal-mediated catalysis. Azide derivatives of d-glucose have been converted to their respective aryltriazoles and screened as ligands for the synthesis of 2-substituted benz-fused azoles and benzimidazoquinazolinones by Cu-catalyzed intramolecular Ullmann type C-heteroatom coupling. Good to excellent yields for a variety of benz-fused heterocyles were obtained for this readily accessible catalytic system.
- Mishra, Nidhi,Singh, Anoop S.,Agrahari, Anand K.,Singh, Sumit K.,Singh, Mala,Tiwari, Vinod K.
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supporting information
p. 389 - 399
(2019/05/06)
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- SMALL MOLECULE ACTIVATORS OF NICOTINAMIDE PHOSPHORIBOSYLTRANSFERASE (NAMPT) AND USES THEREOF
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Provided herein are small molecule activators of Nicotinamide Phosphoribosyltransferase (NAMPT), compositions comprising the compounds, and methods of using the compounds and compositions.
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Paragraph 01126; 01147
(2018/08/03)
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- A Synthesis of Benzothiazoles and Indoles by Direct C(sp2)-I Activation Catalyzed by Copper(II) on Silica-Coated Magnetite Nanoparticles
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N-Substituted 2-amino-1,3-benzothiazoles and 2,3-disubstituted indoles were prepared by C-S and C-C cross-coupling reactions of 2-iodoanilines with isothiocyanates or 1,3-dicarbonyl compounds, respectively, in the presence of magnetic nanoparticles functionalized with a copper(II)-Schiff base complex as an efficient and reusable catalyst.
- Moghadam, Faeze Kiani,Jarrah, Najmeh,Mashayekh-Salehi, Ali,Ghanbaripour, Rashid
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p. 1665 - 1668
(2016/07/06)
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- A practical synthesis of 2-aminobenzothiazoles via copper(I)-catalyzed tandem reaction of 2-iodoanilines with isothiocyanates in ionic liquids
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A copper(I)-catalyzed tandem reaction of 2-iodoanilines with isothiocyanates was achieved in hydrophobic [bmim][PF6] ionic liquid under mild conditions, generating a variety of 2-aminobenzothiazoles in good to excellent yields. The tandem reaction that was carried out in [bmim][PF6] has some obvious advantages such as accelerated reaction rate and increased yield as compared with the reaction run in volatile solvents such as toluene. Furthermore, the CuI/1,10-phenanthroline catalytic system can be reused up to eight times without loss of activity and efficiency.
- Chen, Ling,Huang, Bin,Nie, Quan,Cai, Mingzhong
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p. 446 - 450
(2016/05/19)
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- Base-mediated N- And O-arylations of NH-containing heterocycles, heterocyclic amines and phenols
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Nucleophilic substitution reactions of N-heterocycles such as imidazole, benzimidazole, indole and pyrazole as well as NH2 or OH containing heterocycles, with electron-deficient aryl halides in the presence of t-BuOK or K2CO3as base and DMSO as solvent are reported. A series of N-aryl azoles, unsymmetric diaryl ethers and diaryl amines were obtained in good yields.
- Ghasemi, Zarrin,Shahrak, Nasim Shahi,Roomi, Behzad Jalali,Zakeri, Ziba
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- Straightforward synthesis of 2-anilinobenzoxazoles and -benzothiazoles via mechanochemical ball-milling-promoted one-pot reactions
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Under mechanochemical ball-milling and solvent-free conditions, a series of 2-anilinobenzoxazoles and -thiazoles were synthesized directly from the one-pot reaction of anilines, CS2, and 2-aminophenol and -thiophenol. This protocol exhibits the
- Zhang, Ze,Wang, Fang-Jian,Wu, Hao-Hao,Tan, Ya-Jun
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supporting information
p. 440 - 441
(2015/05/27)
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- Postsynthetic modification of IRMOF-3 with a copper iminopyridine complex as heterogeneous catalyst for the synthesis of 2-aminobenzothiazoles
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A copper iminopyridine complex has been immobilized on to a metal-organic framework (MOF) through postsynthetic modification of IRMOF-3. The modified MOFs were fully demonstrated by using a variety of methods, and the structural integrity of the modified
- Liu, Jie,Zhang, Xiaobin,Yang, Jin,Wang, Lei
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p. 198 - 203
(2014/03/21)
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- Synthesis of N-substituted-2-aminobenzothiazoles using nano copper oxide as a recyclable catalyst under ligand-free conditions, in reusable PEG-400 medium
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A simple and practical method for the synthesis of N-substituted-2- aminobenzothiazoles via a cross-coupling reaction of 2-iodo anilines with isothiocyanates is envisaged using nano copper oxide as a recyclable catalyst and Cs2CO3 as a base in PEG-400, as a bio-degradable, reusable, inexpensive and non-toxic reaction medium, under ligand-free conditions. The present tandem process underlines environmental acceptability to access a wide range of N-substituted-2-aminobenzothiazoles in good to excellent yields.
- Gaddam, Satish,Kasireddy, Harshavardhan Reddy,Konkala, Karnakar,Katla, Ramesh,Durga, Nageswar Yadavalli Venkata
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p. 732 - 736
(2014/06/09)
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- Ligand- and solvent-free synthesis of 2-aminobenzothiazoles by copper-catalyzed tandem reaction of 2-haloanilines with isothiocyanates
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We report an environmentally friendly, efficient and practical method for the synthesis of 2-aminobenzothiazoles by a copper(II)-catalyzed tandem reaction of 2-haloanilines with isothiocyanates under ligand- and solvent-free conditions in air. The developed methodology conforms to the principles of 'green chemistry' and addresses the shortage of such methods for the synthesis of 2-aminobenzothiazoles. The reaction is quite general and generates a variety of 2-aminobenzothiazoles in good to excellent yields. Copyright
- Yao, Ruiya,Liu, Haiyi,Wu, Yichao,Cai, Mingzhong
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p. 109 - 113
(2013/03/13)
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- Direct transition metal-free C-S bond formation: Synthesis of 2-aminobenzothiazole derivatives via base-mediated approach
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A general, efficient, and more practical protocol for the base-mediated intermolecular or intramolecular S-arylation leading to the 2-aminobenzothiazole derivatives is reported. Remarkably, all reactions were carried out under transition-metal-free conditions with good to excellent yields, rendering the methodology presented herein highly valuable from both environmental and economic points of view.
- Wang, Rui,Chen, Zhi,Yue, Liang,Pan, Wei,Zhao, Jun-Jie
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experimental part
p. 4529 - 4531
(2012/09/22)
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- A practical synthesis of 2-aminobenzothiazoles via the tandem reactions of 2-haloanilines with isothiocyanates catalyzed by immobilization of copper in MCM-41
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The heterogeneous tandem reactions of 2-haloanilines with isothiocyanates were achieved in DMSO using Et3N as base at 80 °C in the presence of a 3-(2-aminoethylamino)propyl-functionalized MCM-41-immobilized copper(II) complex [MCM-41-2N-CuSO4], yielding a variety of 2- aminobenzothiazoles in good to excellent yields. This heterogeneous copper catalyst exhibited higher activity than CuSO4 and can be recovered and recycled by a simple filtration of the reaction solution and used for at least 10 consecutive trials without any decreases in activity.
- Xiao, Ruian,Hao, Wenyan,Ai, Jinting,Cai, Ming-Zhong
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experimental part
p. 44 - 50
(2012/04/17)
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- Iron-catalyzed tandem reactions of ortho-aminobenzenethiols with isothiocyanates leading to 2-aminobenzoazoles under ligand-and solvent-free conditions
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An efficient route to synthesize a variety of 2-aminobenzoazoles has been discovered. It involves the reaction of ortho-aminobenzenethiols with isothiocyanates via iron-catalyzed tandem addition-annulations process under ligand and solvent free conditions on silica gel surface. Copyright Taylor &Francis Group, LLC.
- Ding, Qiuping,Cao, Banpeng,Yang, Qin,Liu, Xianjin,Peng, Yiyuan
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experimental part
p. 1782 - 1789
(2011/10/02)
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- Merrifield resin supported phenanthroline-Cu(I): A highly efficient and recyclable catalyst for the synthesis of 2-aminobenzothiazoles via the reaction of 2-haloanilines with isothiocyanates
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A novel Merrifield resin supported phenanthroline-Cu(I) complex has been developed and used as a highly efficient and recyclable catalyst in the reaction of 2-halobenzenamines with isothiocyanates for the synthesis of 2-aminobenzothiazoles. The reactions
- Yang, Jin,Li, Pinhua,Wang, Lei
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experimental part
p. 5543 - 5549
(2011/08/06)
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- Synthesis of 2-aminobenzothiazoles via copper(I)-catalyzed cross-coupling with part-per-million catalyst loadings
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An efficient protocol has been developed for the preparation of 2-aminobenzothiazoles via a copper(I)-catalyzed tandem reaction of 2-iodoanilines with isothiocyanates at very low catalyst loadings [typically 50ppm of copper(I) iodide (CuI)]. A variety of 2-iodoanilines could be cross-coupled with isothiocyanates, affording 2-aminobenzothiazoles in moderate to good yields (49-93%) under the given conditions. The turnover number (TON) of this reaction reaches 67,000 and the reaction could be scaled up, at least, to the gram-scale. Copyright
- Sun, Ya-Lei,Zhang, Yuan,Cui, Xiao-Hui,Wang, Wei
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supporting information; experimental part
p. 1174 - 1178
(2011/07/09)
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- Iron-catalyzed one-pot synthesis of 2-aminobenzothiazoles from 2-aminobenzethiols and isothiocyanates under ligand-free conditions in water
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A practical and efficient method for the synthesis of 2-aminobenzothiazoles has been developed via an iron-catalyzed one-pot tandem reaction. Various 2-aminobenzothiazoles were conveniently synthesized in moderate to excellent yields. It is highlighted that the reaction is conducted under ligand-free conditions in water. The Japan Institute of Heterocyclic Chemistry.
- Wang, Wenying,Zhong, Wenying,Zhou, Runxia,Yu, Jinsheng,Dai, Juan,Ding, Qiuping,Peng, Yiyuan
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experimental part
p. 2841 - 2847
(2011/04/16)
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- Copper(I)-catalyzed cascade synthesis of 2-arylsulfanyl-arylcyanamides
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We have developed a ligand-assisted copper(I)-catalyzed two sequential heteroarylation sequence. An intramolecular S-arylation is followed by an intermolecular N-arylation leading to the direct synthesis of N-aryl-2-aminobenzothiazoles. In most cases however, the 2-arylsulfanyl- arylcyanamide was the major product obtained via an intramolecular C-S bond formation, associated with C-S bond breakage, followed by an intermolecular S-arylation. The selectivity of this ligand-assisted reaction is quite different as compared to that of ligand-free reactions and the rates are much faster giving good yields of products. Various cyanamides can be prepared in excellent yields from their corresponding 1-substituted thioureas with or without the assistance of a ligand with a catalytic quantity of copper(I).
- Sahoo, Santosh K.,Jamir, Latonglila,Guin, Srimanta,Patel, Bhisma K.
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experimental part
p. 2538 - 2548
(2010/12/29)
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- Copper-catalyzed intermolecular amination of acidic aryl C-H bonds with primary aromatic amines
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A copper-catalyzed intermolecular aerobic oxidative C-H bond amination of various polyfluorobenzenes with an array of primary aromatic amines was achieved for the first time. The reactivity of the polyfluorobenzenes was observed to depend on the acidity of C-H bonds. Under similar reaction conditions, the C-H bond amination of azoles also occurred.
- Zhao, Huaiqing,Wang, Min,Su, Weiping,Hong, Maochun
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supporting information; experimental part
p. 1301 - 1306
(2010/07/03)
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- Copper-catalyzed tandem reactions of 2-halobenzenamines with isothiocyanates under ligand- and base-free conditions
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A ligand-free copper-catalyzed reaction of 2-halobenzenamines with isothiocyanates has been developed for the synthesis of 2-aminobenzothiazoles. In the presence of CuBr and TBAB (tetra-n-butyl ammonium bromide, additive), a variety of 2-halobenzenamines underwent the reaction with isothiocyanates at 40 °C, affording 2-aminobenzothiazoles in moderate to excellent yields. It is noteworthy that the reaction is conducted under mild, relatively low catalyst loading, and ligand- and base-free conditions.
- Guo, Yan-Jin,Tang, Ri-Yuan,Zhong, Ping,Li, Jin-Heng
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supporting information; experimental part
p. 649 - 652
(2010/04/23)
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- Synthesis of 2-aminobenzothiazole via FeCl3-catalyzed tandem reaction of 2-iodoaniline with isothiocyanate in water
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An FeCl3-catalyzed tandem reaction of 2-iodoaniline with isothiocyanate in water is described, which provides an environmentally benign, efficient, and practical route for the generation of 2-aminobenzothiazole. This present tandem process shows broad substrate scope in the presence of octadecyltrimethylammonium chloride as a phase-transfer catalyst. In addition, the reaction media can be recovered and recycled without loss of efficiency.
- Ding, Qiuping,Cao, Banpeng,Liu, Xianjin,Zong, Zhenzhen,Peng, Yi-Yuan
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supporting information; experimental part
p. 1607 - 1610
(2010/12/19)
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- Iron-catalyzed tandem reactions of 2-halobenzenamines with isothiocyanates leading to 2-aminobenzothiazoles
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A highly practical method for the synthesis of 2-aminobenzothiazoles has been developed through an iron-catalyzed tandem reaction. The present tandem process allows the assembly of a wide range of 2-aminobenzothiazoles by the reactions of 2-halobenzenamin
- Qiu, Jing-Wen,Zhang, Xing-Guo,Tang, Ri-Yuan,Zhong, Ping,Li, Jin-Heng
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supporting information; scheme or table
p. 2319 - 2323
(2009/12/29)
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- Synthesis of Unsymmetrical Diheteroarylbenzenes: Benzoazole and Quinazoline Derivatives
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Four different types of structures, namely 8, 14, 17 and 18 have been prepared for the first time.No more than five steps are needed to synthesize them using 4-nitroaniline as starting material.In order to confirm the proposed structures, some independent
- Garin, Javier,Melendez, Enrique,Merchan, Francisco L.,Merino, Pedro,Orduna, Jesus,Tejero, Tomas
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p. 359 - 363
(2007/10/02)
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