- Molecular iodine-mediated synthesis of thiocarbamates from thiols, isocyanides and water under metal-free conditions
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A simple and practical molecular iodine-mediated method for the efficient construction of thiocarbamates from isocyanides, thiols and water under metal-free and mild conditions has been developed. A variety of thiocarbamates were easily synthesized through this methodology, which has the advantages of simple operation, eco-friendly conditions, good functional group tolerance, and readily accessible raw materials.
- Bao, Wen-Hu,Wu, Chao,Wang, Jing-Ting,Xia, Wen,Chen, Ping,Tang, Zilong,Xu, Xinhua,He, Wei-Min
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supporting information
p. 7025 - 7029
(2018/10/02)
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- Iodine-catalyzed formation of substituted 2-aminobenzothiazole derivatives in PEG400
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An iodine-catalyzed formation of substituted 2-aminobenzothiazole derivatives is herein described using hydrogen peroxide as an oxidant in PEG400. The method enabled an efficient environmentally sound access to this valuable scaffold in moderate to excellent yields under metal-free conditions.
- Dumonteil,Hiebel,Scherrmann,Berteina-Raboin
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p. 73517 - 73521
(2016/08/19)
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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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- 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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- Water-Mediated Synthesis of Benzazole and Thiourea Motifs by Reacting Naturally Occurring Isothiocyanate with Amines
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An efficient, green, and facile method has been developed for the synthesis of benzazole and thiourea analogues from naturally occurring erucin in moderate to good yields. The reaction was carried out in water without using any metal catalyst or base. The present method tolerated the various functional groups on aromatic rings and also applicable for other isothiocyanates.
- Sharma, Ritika,Bala, Manju,Verma, Praveen Kumar,Singh, Bikram
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supporting information
p. 2106 - 2114
(2015/09/01)
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- Copper-catalyzed synthesis of 2-aminobenzothiazoles from carbodiimide and sodium hydrosulfide
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An efficient copper-catalyzed method for the synthesis of a variety of 2-aminobenzothiazoles has been developed. The reaction proceeded from carbodiimide and sodium hydrosulfide via a tandem reaction in the presence of copper(ii) trifluoromethanesulfonate to afford the corresponding 2-aminobenzothiazole derivatives in good to perfect yields. This journal is the Partner Organisations 2014.
- Zeng, Weilan,Dang, Pan,Zhang, Xiaoyun,Liang, Yun,Peng, Caiyun
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p. 31003 - 31006
(2014/08/05)
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- Copper/N,N,N',N'-tetramethylethylenediamine-catalyzed synthesis of N-substituted benzoheterocycles via C-S cross-coupling at ambient temperature in water
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Copper/N,N,N',N'-tetramethylethylenediamine (Cu/TMEDA)-catalyzed ambient temperature tandem reactions of isothiocyanates with 2-iodophenols or 2-iodoanilines in water without the protection of an inert atmosphere are described, which provide a simple, rapid, environmental method for the synthesis of a variety of 2-iminobenzo-1, 3- oxathioles and 2-aminobenzothiazoles in good yields. More important, the present reaction process needs only low amounts of copper catalyst (1mol%) and can yield the products on a gram scale.
- Zhao, Na,Liu, Liang,Wang, Fei,Li, Jia,Zhang, Wu
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supporting information
p. 2575 - 2579
(2014/09/17)
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- Convenient and reliable routes towards 2-aminothiazoles: Palladium-catalyzed versus copper-catalyzed aminations of halothiazoles
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Two efficient methods for the amination of 2-halothiazoles are presented here. A first protocol requires a Pd/L system. Several 2-aminothiazoles were synthesized under optimized conditions and isolated in good yields. The first palladium-catalyzed C-N coupling reactions between 2-halothiazoles and primary alkylamines are presented. In a second part, ligand-free copper-catalyzed aminations of 2-halothiazoles by alkylamines and aniline in a green solvent have been developed. The protocol is very effective for primary and secondary amines and perfectly tolerates the presence of another halide moiety on the 2-halothiazole. The reaction occurs under the assistance of microwave irradiation, which drastically decreases the reaction time. The reaction leads to the formation of 2-aminothiazoles, key molecules in pharmaceutical research. Copyright
- Toulot, Stephanie,Heinrich, Timo,Leroux, Frederic R.
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supporting information
p. 3263 - 3272
(2013/12/04)
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- Laccase-catalysed homocoupling of primary aromatic amines towards the biosynthesis of dyes
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Coloured disubstituted benzoquinonimine trimeric structures are obtained as main reaction products of the oxidation of p-electron donor pri-mary aromatic amines using two different laccases, CotA-laccase from Baccilus subtilus and TvL from Trametes versicolor. These orange-red to purple products, presenting high molar extinction coeffi-cients, presumably result from oxidative homocou-pling reactions, through the formation of N-C bonds at positions 2 and 5, of the laccase oxidised inter-mediate as showed in the proposed oxidative path-way. The product of 1,4-phenylenediamine is shown to be the trimer known as Bandrowski's base which has an established role in hair and fur dyeing. Our results also show that the occurrence and/or rates of oxidation of aromatic amines are strongly dependent on the presence of p-electron releasing substituents in the aromatic ring and are independent on the properties of the enzyme used. Overall our data con-tribute for (i) understanding key features of laccase reactivity with p-substituted aromatic amines and (ii) establishing enzymatic processes that lead to the syn-thesis of coloured bio-products under mild condi-tions with potential impact in the cosmetic and dye industries.
- Sousa, Ana Catarina,Martins, Lígia O.,Robalo, M. Paula
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supporting information
p. 2908 - 2917
(2014/03/21)
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- Cobalt-catalyzed oxidative isocyanide insertion to amine-based bisnucleophiles: Diverse synthesis of substituted 2-aminobenzimidazoles, 2-aminobenzothiazoles, and 2-aminobenzoxazoles
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Cobalt catalysis: Synthesis of substituted 2-aminobenzimidazoles, 2-aminobenzothiazoles, and 2-aminobenzoxazoles was achieved by using cobalt(II) acetate catalyzed isocyanide insertion to o-diaminobenzene, 2-aminobenzenethiol, and 2-aminophenol derivatives in 1,4-dioxane (see scheme). It was found that the reaction proceeded efficiently to give the desired products in up to 95 % isolated yields by C-N and C-S (O, N) formation in a single step. Copyright
- Zhu, Tong-Hao,Wang, Shun-Yi,Wang, Gao-Nan,Ji, Shun-Jun
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supporting information
p. 5850 - 5853
(2013/06/26)
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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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- An "on-water" exploration of CuO nanoparticle catalysed synthesis of 2-aminobenzothiazoles
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An "on-water" one-pot process has been engineered for the preparation of 2-aminobenzothiazole from ortho-halo (-F, -Cl, -Br and -I) substituted unsymmetrical thioureas. For ortho -I and -Br substrates the reactions afford 2-aminobenzothiazoles under metal free condition promoted by base. However, the relatively inert ortho -Cl and -F substrates undergo intramolecular arylthiolation only in the presence of CuO nanoparticles yielding 2-aminobenzothiazoles. This methodology provides easy access to aminobenzothiazoles utilising even the ortho -Cl and -F substrates. The catalyst is recyclable several times without loss of substantial activity. Other remarkable features include the wide range of functional group tolerance, absence of chromatographic purification (for ortho -I and -Br substrates) and providing moderate to excellent yield of the products under mild conditions, thus rendering the methodology as a highly eco-friendly alternative to the existing methods.
- Rout, Saroj Kumar,Guin, Srimanta,Nath, Jayashree,Patel, Bhisma K.
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p. 2491 - 2498
(2013/02/21)
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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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- 1,10-Phenanthroline-catalyzed tandem reaction of 2-iodoanilines with isothiocyanates in water
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The 1,10-phenanthroline-catalyzed tandem reaction of 2-iodoaniline with isothiocyanate in water is described, which provides an environmentally benign, efficient and simple route for the preparation of 2-aminobenzothiazoles. The present tandem process shows broad substrate scope in the absence of transition metals and phase-transfer catalysts. Copyright
- Zhang, Wu,Yue, Yun,Yu, Dan,Song, Lei,Xu, Yang-Yang,Tian, Yu-Jie,Guo, Yu-Jun
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supporting information
p. 2283 - 2287
(2012/11/07)
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- DDQ-promoted C-S bond formation: Synthesis of 2-aminobenzothiazole derivatives under transition-metal-, ligand-, and base-free conditions
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A transition-metal-free method for the intramolecular S-arylation of o-halobenzothiaoureas via DDQ-mediated leading to the 2-aminobenzothiazole derivatives is reported. The reactions are performed at room temperature under ligand- and base-free conditions with good to excellent yields. Georg Thieme Verlag Stuttgart · New York.
- Wang, Rui,Yang, Wen-Juan,Yue, Liang,Pan, Wei,Zeng, Hong-Yao
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experimental part
p. 1643 - 1648
(2012/08/07)
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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 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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- One-pot synthesis of five and six membered N, O, S-heterocycles using a ditribromide reagent
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In a one-pot procedure, bromine less brominating reagent 1,1′-(ethane-1,2-diyl)dipyridinium bistribromide (EDPBT) has been utilized as an efficient desulfurizing agent for the construction of a library of heterocycles containing N, O, and S starting from aryl/alkyl isothiocyanates. In this approach, aryl/alkyl isothiocyanate reacts with o-phenylenediamine (o-PD), o-aminophenol, and o-aminothiophenol to form their monothiourea which on desulfurization with EDPBT led to the formation of corresponding 2-aminobenzimidazoles, 2-aminobenzoxazoles, and 2-aminobenzothiazoles, respectively. An interesting regioselectivity was observed for unsymmetrical thiourea having a naphthyl moiety on the one side and an ortho amino or an ortho hydroxy phenyl group on the other side giving a completely different product which is mainly dependent on the nature of the nucleophiles (-OH or -NH 2). Further, the bis-thioureas resulted from the aliphatic 1,2-diamine with 2 equiv of aryl isothiocyanates on treatment with EDPBT gave imidazolidenecarbothioamides, whereas bis-thioureas resulted from aromatic 1,2-diamine yielded benzimidazoles with concurrent expulsion of an isothiocyanate unit. This method is simple and applied to various substrates which are amenable to bromination that reveals the desulfurizing ability of EDPBT predominating over its brominating ability. Finally, the spent reagent EDPDB can be recovered, regenerated, and reused without any loss of activity.
- Yella, Ramesh,Patel, Bhisma K.
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experimental part
p. 754 - 763
(2010/11/03)
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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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- An effcient synthesis of 2-aminobenzoxazoles and 2-aminobenzothiazazoles from 2-aminophenols or 2-aminothiophenols and isoselenocyanates
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An expeditious method to access 2-aminobenzoxazoles and 2-aminobenzothiazoles from various substituted 2-aminophenols and 2-aminothiophenols, respectively, with isoselenocyanates in a one pot procedure is reported. Elemental Se precipitates nearly quantitatively in the reaction without any deselenizing agent and it can be reused. A possible mechanism for the formation of the target products is proposed. The Japan Institute of Heterocyclic Chemistry.
- Xie, Yuanyuan,Zhang, Fan,Chen, Xiaodong,Li, Jianjun
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experimental part
p. 2087 - 2096
(2011/03/23)
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- Ligand-free copper-catalyzed synthesis of substituted benzimidazoles, 2-aminobenzimidazoles, 2-aminobenzothiazoles, and benzoxazoles
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(Chemical Equation Presented) The synthesis of substituted benzimidazoles, 2-aminobenzimidazoles, 2-aminobenzothiazoles, and benzoxazoles is described via intramolecular cyclization of o-bromoaryl derivatives using copper(II) oxide nanoparticles in DMSO under air. The procedure is experimentally simple, general, efficient, and free from addition of external chelating ligands. It is a heterogeneous process and the copper(II) oxide nanoparticles can be recovered and recycled without loss of activity. 2009 American Chemical Society.
- Saha, Prasenjit,Ramana, Tamminana,Purkait, Nibadita,Ali, Md. Ashif,Paul, Rajesh,Punniyamurthy, Tharmalingam
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experimental part
p. 8719 - 8725
(2010/02/28)
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- Process for the manufacture of 2-amino-aryleno-thiazole compounds and of derivatives thereof N-substituted in the ring
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2-Amino-aryleno-thiazoles in which the amino group in 2-position can be substituted by aryl, alkyl and/or cycloalkyl, and 2-imino-aryleno-thiazolines substituted at the ring nitrogen by aryl, alkyl or cycloalkyl are produced by cyclization of arylthioureas carrying corresponding substituents at the respective nitrogen atom, using thionyl chloride as cyclization agent. The advantage of the improved process resides in that the amount of sulfur formed is very low and that the other by-products are easy to separate and can be used further. The thiazoles and thiazolines are obtained in a high yield and purity. They are valuable starting compounds, especially for the manufacture of dyestuffs.
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