- A biomass-derived N-doped porous carbon catalyst for the aerobic dehydrogenation of nitrogen heterocycles
-
N-doped porous carbon (NC) was synthesized from sugar cane bagasse, which is a sustainable and widely available biomass waste. The preferred NC sample had a well-developed porous structure, a graphene-like surface morphology and different N species. More
- Cui, Fu-Jun,Guo, Fu-Hu,Liu, Jing-Jiang,Liu, Xiao-Yu,Quan, Zheng-Jun,Ullah, Arif,Wang, Xi-Cun,Zhu, Ji-Hua
-
supporting information
p. 1791 - 1799
(2022/01/31)
-
- Visible-Light Carbon Nitride-Catalyzed Aerobic Cyclization of Thiobenzanilides under Ambient Air Conditions
-
A metal-free heterogeneous photocatalysis has been developed for the synthesis of benzothiazoles via intramolecular C-H functionalization/C-S bond formation of thiobenzanilides by inexpensive graphitic carbon nitride (g-C3N4) under visible-light irradiation. This reaction provides access to a broad range of 2-substituted benzothiazoles in high yields under an air atmosphere at room temperature without addition of a strong base or organic oxidizing reagents. In addition, the catalyst was found to be stable and reusable after five reaction cycles.
- Bai, Jin,Yan, Sijia,Zhang, Zhuxia,Guo, Zhen,Zhou, Cong-Ying
-
p. 4843 - 4848
(2021/06/28)
-
- Photocatalyst- And Transition-Metal-Free Visible-Light-Promoted Intramolecular C(sp2)-S Formation
-
A photocatalyst- and transition-metal-free visible-light-induced cyclization of ortho-halothiobenzanilides has been developed. Upon irradiation with visible light, substrates undergo dehalogenative cyclization to 2-aryl benzothiazoles with high efficiency and selectivity. This photocyclization exhibits a high tolerance to various functional groups, is applicable for the synthesis of 2-alkyl benzothiazoles, and is easy to set up for gram-scale reaction.
- Wang, Hao,Wu, Qi,Zhang, Jian-Dong,Li, Hai-Yan,Li, Hong-Xi
-
p. 2078 - 2083
(2021/04/05)
-
- Method for preparing alkyl benzothiazole derivative under visible light
-
The invention discloses a method for preparing an alkyl benzothiazole derivative under visible light, which specifically comprises the following steps: under the protection of inert gas, adding N-(2-bromophenyl) alkyl thioamide and inorganic base into a reaction container provided with a stirring device, then adding dimethyl sulfoxide, stirring and reacting for 24 hours at room temperature under the irradiation of visible light, and obtaining the alkyl benzothiazole derivative. Under the condition of not adding any photosensitizer or transition metal catalyst, sodium phosphate is used as alkali, and under the irradiation of a 45W household compact fluorescent lamp, a series of intramolecular cross-coupling reactions of N-(2-bromophenyl) alkyl thioamide are realized. In addition, the alkylbenzothiazole derivative can be obtained with high yield. The whole process is green, efficient and easy to operate, and the method is a good method for synthesizing the alkylbenzothiazole derivative.
- -
-
Paragraph 0027-0029
(2021/06/22)
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- Insertion Reaction of 2-Halo- N -allylanilines with K 2S Involving Trisulfur Radical Anion: Synthesis of Benzothiazole Derivatives under Transition-Metal-Free Conditions
-
A synthesis of benzothiazole derivatives through the reaction of 2-halo- N -allylanilines with K 2S in DMF is developed. The trisulfur radical anion S 3· -, which is generated in situ from K 2S in DMF, initiates
- Liu, Xin-Yu,Zhao, Yan-Wei,Jiang, Tian,Rao, Weidong,Wang, Shun-Yi
-
p. 971 - 977
(2020/12/28)
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- Photocatalytic green synthesis of benzazoles from alcohol oxidation/toluene sp3C-H activation over metal-free BCN: effect of crystallinity and N-B pair exposure
-
Porous borocarbonitride (P-BCN), with the characteristics of enhanced crystallinity and improved N-B pair exposure, was prepared with a simple KCl-assisted molten salt strategy. Efficient heterogeneous photocatalytic tandem synthesis of benzazoles from alcohol oxidation/toluene sp3C-H activation was achieved firstly over the metal-free P-BCN using visible light and the green oxidant O2, with only water as a by-product. Variouso-thio/hydroxy/aminoanilines and alcohols or toluenes could be converted to the corresponding 2-substituted benzothiazoles, benzoxazoles and benzimidazoles with good to excellent photocatalytic performance. The improved photocatalytic performance in comparison to bulk BCN should be due to the crystallinity-enhancement-induced improvement in charge separation and transmission. The increased N-B pair exposure promoted superoxide radical generation due to the electron-enriched N atoms, as well as improved oxidation ability due to the valence band constructed by the B 2p orbital. This work presents a green and efficient synthetic strategy towards benzazoles and other fine chemicalsviametal-free heterogeneous photocatalysis.
- Cheng, Hongmei,Gao, Xue,Jiang, Heyan,Sun, Bin,Zang, Cuicui
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p. 7955 - 7962
(2021/12/27)
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- Visible-light-mediated organoboron-catalysed metal-free dehydrogenation of N-heterocycles using molecular oxygen
-
The surge of photocatalytic transformation not only provides unprecedented synthetic methods, but also triggers the enthusiasm for more sustainable photocatalysts. On the other hand, oxygen is an ideal oxidant in terms of atom economy and environmental friendliness. However, the poor reactivity of oxygen at the ground state makes its utilization challenging. Herein, a visible-light-induced oxidative dehydrogenative process is disclosed, which uses an organoboron compound as the photocatalyst and molecular oxygen as the sole oxidant.Viathis approach, an array of N-heterocycles have been accessed under metal-free mild conditions, in good to excellent yields.
- Wei, Lanfeng,Wei, Yu,Xu, Liang,Zhang, Jinli
-
supporting information
p. 4446 - 4450
(2021/06/30)
-
- Method for preparing N - heterocyclic ring through visible light mediated dehydrogenation
-
The invention discloses a method for preparing N - heterocyclic rings through visible light mediated dehydrogenation, and the reaction can be carried out under the conditions of room temperature and visible light without heating. The novel tetra-coordination N-N - diaryl chelating borate compound serves as a photocatalyst, so that the use of a noble metal photocatalyst is avoided, precious metal residue in the reaction product can be reduced as much as possible, and the method is more suitable for synthesizing bioactive molecules.
- -
-
Paragraph 0142-0147
(2021/10/02)
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- Iodine-promoted ring-opening methylation of benzothiazoles with dimethyl sulfite
-
A halogen-bond promoted ring-opening methylation of benzothiazoles has been developed using dimethyl sulphite as a methylating reagent in the presence of a base. This approach represents a simple and efficient synthesis ofN-methyl-N-(o-methylthio)phenyl amides, and features direct construction of both N-Me and S-Me bonds in a one-pot reaction through the decomposition of easily prepared benzothiazoles.
- Guo, Ying-Qiong,Chen, Fan,Deng, Chen-Liang,Zhang, Xing-Guo
-
supporting information
p. 1923 - 1926
(2021/03/02)
-
- Exogenous Photosensitizer-, Metal-, and Base-Free Visible-Light-Promoted C-H Thiolation via Reverse Hydrogen Atom Transfer
-
Visible-light-driven, intramolecular C(sp2)-H thiolation has been achieved without addition of a photosensitizer, metal catalyst, or base. This reaction induces the cyclization of thiobenzanilides to benzothiazoles. The substrate absorbs visible light, and its excited state undergoes a reverse hydrogen-atom transfer (RHAT) with 2,2,6,6-tetramethylpiperidine N-oxyl to form a sulfur radical. The addition of the sulfur radical to the benzene ring gives an aryl radical, which then rearomatizes to benzothiazole via RHAT.
- Xu, Ze-Ming,Li, Hong-Xi,Young, David James,Zhu, Da-Liang,Li, Hai-Yan,Lang, Jian-Ping
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p. 237 - 241
(2019/01/10)
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- Photocatalytic Oxidative C-H Thiolation: Synthesis of Benzothiazoles and Sulfenylated Indoles
-
We report studies on the photocatalytic formation of C-S bonds to form benzothiazoles via an intramolecular cyclization and sulfenylated indoles via an intermolecular reaction. Cyclic voltammetry (CV) and density functional theory studies suggest that benzothiazole formation proceeds via a mechanism that involves an electrophilic sulfur radical, while the indole sulfenylation likely proceeds via a nucleophilic sulfur radical adding into a radical cationic indole. These conditions were successfully extended to several thiobenzamides and indole substrates.
- Aceves, Ernesto Millan,Albright, Samuel T.,Cedano, Mario R.,Dinh, Andrew N.,Gustafson, Jeffrey L.,Nguyen, Ashley D.,Smith, Diane K.
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p. 1648 - 1655
(2019/08/26)
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- Method for synthesizing benzothiazole by microwave radiation of benzothioamide compound in aqueous phase
-
The invention discloses a method for synthesizing benzothiazole by microwave radiation of a benzothioamide compound in an aqueous phase. The method includes the steps: adding the benzothioamide compound into the aqueous phase under microwave conditions; performing cyclization under alkaline conditions to generate the benzothiazole. The method for preparing the benzothiazole is environmentally friendly, simple and convenient in operation, safe, cheap and efficient. Compared with the prior art, the method is applicable to a lot of functional groups, high in yield, few in by-products, simple in operation, safe, low in cost and environmentally friendly.
- -
-
Paragraph 0013; 0016
(2019/02/13)
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- An efficient synthesis of benzothiazole using tetrabromomethane as a halogen bond donor catalyst
-
An efficient and mild protocol has been developed for the synthesis of 2-substituted benzothiazole under solvent- and metal-free conditions using CBr4 as the catalyst. This process involves the activation of a thioamide through halogen bond formation between the sulphur atom of the thioamide and bromine atom of the CBr4 molecule. The presence of halogen-bonding interaction between N-methylthioamides and tetrabromomethane has been demonstrated with several control experiments, spectroscopic analysis and density functional theory (DFT). This methodology has a wide substrate scope for the synthesis of both 2-alkyl and 2-aryl substituted benzothiazoles.
- Kazi, Imran,Sekar, Govindasamy
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p. 9743 - 9756
(2019/12/02)
-
- Efficient CDI/CH3SO3H-catalyzed, microwave-assisted synthesis of 2-substituted benzothiazoles
-
CDI combined with CH3SO3H was found to be highly effective for the cyclization of 2-aminothiophenol derivatives with carboxylic acids under MW condition. Fourteen benzothiazole derivatives were synthesized in good yield and their structures were characterized by1H-NMR,13C-NMR, IR and mass spectrometry. This simple, rapid synthetic method is believed to provide a useful process for the synthesis of 2-substituted benzothiazole compounds.
- Li, Yao-Wei,Zhang, Pei-Ming,Li, Rui,Bai, Yan,Yu, Yu,Gan, Zong-Jie
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supporting information
p. 34 - 39
(2019/05/04)
-
- Visible-Light-Promoted Iron-Catalyzed C(sp2)–C(sp3) Kumada Cross-Coupling in Flow
-
A continuous-flow, visible-light-promoted method has been developed to overcome the limitations of iron-catalyzed Kumada–Corriu cross-coupling reactions. A variety of strongly electron rich aryl chlorides, previously hardly reactive, could be efficiently coupled with aliphatic Grignard reagents at room temperature in high yields and within a few minutes’ residence time, considerably enhancing the applicability of this iron-catalyzed reaction. The robustness of this protocol was demonstrated on a multigram scale, thus providing the potential for future pharmaceutical application.
- Wei, Xiao-Jing,Abdiaj, Irini,Sambiagio, Carlo,Li, Chenfei,Zysman-Colman, Eli,Alcázar, Jesús,No?l, Timothy
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supporting information
p. 13030 - 13034
(2019/07/18)
-
- Peroxide-mediated oxidative coupling of primary alcohols and disulfides: Synthesis of 2-substituted benzothiazoles
-
A peroxide-mediated protocol for the synthesis of 2-substituted benzothiazoles was developed, starting from bis(o-aminophenyl) disulfides and primary alcohols. Eleven differently 2-substituted benzothiazoles were prepared in moderate to excellent yields using di-tert-butyl peroxide (DTBP) as an oxidant.
- Padilha, Nathalia B.,Penteado, Filipe,Salom?o, Maria C.,Lopes, Eric F.,Bettanin, Luana,Hartwig, Daniela,Jacob, Raquel G.,Lenard?o, Eder J.
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supporting information
p. 1587 - 1591
(2019/05/21)
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- Method for preparing benzothiazole compound through microwave catalysis in water phase
-
The invention discloses a method for preparing a benzothiazole compound through/under microwave catalysis in a water phase. A water-soluble coordination compound is used as a catalyst, and a reactionof inorganic sulfide, 2-iodoaniline and aldehyde is efficiently catalyzed through microwaves in a pure water phase. The method for preparing the benzothiazole compound is environmentally friendly, convenient to operate, safe, cheap and efficient. Compared with the prior art, the method is applied to a large quantity of functional groups, high in yield, simple to operate, safe, low in cost and environmentally friendly and produces a few byproducts.
- -
-
Paragraph 0044
(2018/05/16)
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- TEMPO-Catalyzed Electrochemical C-H Thiolation: Synthesis of Benzothiazoles and Thiazolopyridines from Thioamides
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Benzothiazoles and thiazolopyridines are widely prevalent in pharmaceuticals and organic materials. Herein, we report a metal- and reagent-free method for the uniform synthesis of benzothiazoles and thiazolopyridines through 2,2,6,6-tetramethylpiperidine-N-oxyl radical (TEMPO)-catalyzed electrolytic C-H thiolation. This dehydrogenative coupling process provides access to a host of benzothiazoles and thiazolopyridines from N-(hetero)arylthioamides. Mechanistic studies suggested that the thioamide substrate was oxidized with the electrochemically generated TEMPO+ through an inner-sphere electron transfer to afford a thioamidyl radical, which undergoes homolytic aromatic substitution to form the key C-S bond.
- Qian, Xiang-Yang,Li, Shu-Qi,Song, Jinshuai,Xu, Hai-Chao
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p. 2730 - 2734
(2017/05/31)
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- Visible-light-induced tandem reaction of o-aminothiophenols and alcohols to benzothiazoles over Fe-based MOFs: Influence of the structure elucidated by transient absorption spectroscopy
-
MIL-100(Fe) and MIL-68(Fe), two Fe-based MOFs, were found to be active for oxidative condensation between alcohols and o-aminothiophenols to form 2-substituted benzothiazoles under visible light irradiation using oxygen (O2) as oxidant. This reaction can be applied to a wide range of substrates with medium to high yield. Controlled experiments and ESR results revealed a superoxide radical (O2-)-mediated pathway, which is derived from the reduction of O2 by photogenerated Fe2+ on Fe–O clusters. The whole multistep reaction is limited by the step of the photo-oxidation of alcohols to aldehydes. MIL-100(Fe) showed catalytic performance superior to that of MIL-68(Fe) because its higher concentration of long-lived (μs time scale) positive holes can be photogenerated over MIL-100(Fe), in contrast to MIL-68(Fe). This study not only provides an economical, sustainable, and thus green process for the production of 2-substituted benzothiazoles, but also illustrates the potential of using transient absorption spectroscopy as an important tool for understanding the photophysics of MOFs, which are believed to show great potential as multifunctional catalysts for light-induced organic transformations.
- Wang, Dengke,Albero, Josep,García, Hermenegildo,Li, Zhaohui
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p. 156 - 162
(2017/04/07)
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- Visible-light-promoted synthesis of benzothiazoles from 2-aminothiophenols and aldehydes
-
A visible-light-promoted synthesis of benzothiazoles from 2-aminothiophenols and aldehydes has been developed. A wide range of aromatic, heteroaromatic and aliphatic aldehydes were successfully applied. The benzothiazole products were prepared in good yields. The reaction was carried out in the absence of transition-metal catalysts and extra additives. A radical reaction pathway was proposed.
- Ye, Lin-miao,Chen, Jie,Mao, Peng,Mao, Zhi-feng,Zhang, Xue-jing,Yan, Ming
-
supporting information
p. 874 - 876
(2017/02/18)
-
- Photoredox-mediated Minisci C-H alkylation of N-heteroarenes using boronic acids and hypervalent iodine
-
A photoredox-mediated Minisci C-H alkylation reaction of N-heteroarenes with alkyl boronic acids is reported. A broad range of primary and secondary alkyl groups can be efficiently incorporated into various N-heteroarenes using [Ru(bpy)3]Cl2 as photocatalyst and acetoxybenziodoxole as oxidant under mild conditions. The reaction exhibits excellent substrate scope and functional group tolerance, and offers a broadly applicable method for late-stage functionalization of complex substrates. Mechanistic experiments and computational studies suggest that an intramolecularly stabilized ortho-iodobenzoyloxy radical intermediate might play a key role in this reaction system.
- Li, Guo-Xing,Morales-Rivera, Christian A.,Wang, Yaxin,Gao, Fang,He, Gang,Liu, Peng,Chen, Gong
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p. 6407 - 6412
(2016/09/28)
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- A simple and efficient route for synthesis of 2-alkylbenzothiazoles
-
The condensation of 2-aminothiophenol with aliphatic aldehydes in the presence of 4? molecular sieves, followed by oxidation with silica gel supported pyridinium chlorochromate offers a simple and efficient route to 2-alkylbenzothiazoles.
- Waengdongbung, Wijitra,Hahnvajanawong, Viwat,Theramongkol, Parinya
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p. 941 - 945
(2016/07/06)
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- Decarboxylative Coupling of α-Keto Acids with ortho-Phenylenediamines Promoted by an Electrochemical Method in Aqueous Media
-
An electrochemical method for the decarboxylative coupling of α-keto acids with ortho-phenylenediamines was developed. The reaction proceeded smoothly in aqueous solution under air and metal catalyst-free conditions to afford 2-substituted benzimidazoles in good yields. Benzothiazoles could also be synthesized by this protocol. (Figure presented.) .
- Wang, Hai-Bin,Huang, Jing-Mei
-
supporting information
p. 1975 - 1981
(2016/07/06)
-
- Electrochemical Synthesis of Benzazoles from Alcohols and o-Substituted Anilines with a Catalytic Amount of CoII Salt
-
An electrochemical synthesis of benzazoles directly from alcohols and o-substituted anilines has been developed. The reaction conditions have been optimized by varying the composition of the electrolyte and the metal salt used as catalyst. The cyclization proceeds smoothly with a catalytic amount of a cobalt salt under air at room temperature to afford 2-substituted benzimidazoles, benzothiazoles, and benzoxazoles in good to excellent yields with a wide substrate scope.
- Lai, Yin-Long,Ye, Jian-Shan,Huang, Jing-Mei
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supporting information
p. 5425 - 5429
(2016/04/09)
-
- Method for catalytic synthesis of 2-substituted benzothiazole compound by utilizing Yb/MCM-41 molecular sieve-based catalyst
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The invention relates to a method for the catalytic synthesis of a 2-substituted benzothiazole compound by utilizing a Yb/MCM-41 molecular sieve-based catalyst. The method comprises the steps of (a) subjecting 2-amino thiophenol, an aldehyde compound and
- -
-
Paragraph 0120; 0121; 0122; 0123; 0124
(2016/10/17)
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- Role of graphene oxide as a heterogeneous acid catalyst and benign oxidant for synthesis of benzimidazoles and benzothiazoles
-
We report the synthesis of benzothiazoles and benzimidazoles using graphene oxide as an effective catalyst with good yields and easy recyclability. Graphene oxide plays the dual role of a metal-free acid catalyst and an oxidizing agent. The mechanism of a
- Dhopte, Kiran B.,Zambare, Rahul S.,Patwardhan, Anand V.,Nemade, Parag R.
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p. 8164 - 8172
(2016/02/05)
-
- Metal- and Oxidant-Free Synthesis of Quinazolinones from β-Ketoesters with o-Aminobenzamides via Phosphorous Acid-Catalyzed Cyclocondensation and Selective C-C Bond Cleavage
-
A general and efficient phosphorous acid-catalyzed cyclocondensation of β-ketoesters with o-aminobenzamides via selective C-C bond cleavage leading to quinazolinones is developed. This reaction proceeds smoothly under metal- and oxidant-free conditions, giving both 2-alkyl- and 2-aryl-substituted quinazolinones in excellent yields. This strategy can also be applied to the synthesis of other N-heterocycles, such as benzimidazoles and benzothiazoles.
- Li, Zhongwen,Dong, Jianyu,Chen, Xiuling,Li, Qiang,Zhou, Yongbo,Yin, Shuang-Feng
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p. 9392 - 9400
(2015/10/12)
-
- Metal-free synthesis of benzothiazoles from disulfides of 2-aminobenzenethiol and carboxylic acid via PCl3-promoted tandem reaction
-
A metal-free process for the synthesis of benzothiazoles via PCl3-promoted cleavage/acylation/ cyclization of disulfides and carboxylic acids has been developed. In addition to acting as the acylating reagent which converted carboxylic acids into acyl chlorides, PCl3 also converted disulfides to thiols, which promoted disulfides of 2-aminobenzenethiol reacted with carboxylic acid to produce benzothiazoles. The developed method is applicable to a wide range of carboxylic acids containing different functional groups.
- Du, Guangyan,Zhu, Ning,Han, Limin,Hong, Hailong,Suo, Quanling
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p. 1723 - 1734
(2015/12/12)
-
- FeCl3/ultrasound mediated reaction of 2-aminothiophenol with aldehydes in water: Synthesis of 2-substituted benzothiazoles of pharmacological interest
-
We report a FeCl3?6H2O mediated green and rapid access to benzothiazole derivatives having a substituent at C-2 via the condensation of 2-aminothiophenol with various aldehydes under ultrasound irradiation and air. The reaction progressed well in water affording the expected products in good yields. Two of these compounds known to be potent anticancer agents showed good interactions with PDE4B in silico and inhibited this enzyme when tested in vitro.
- Srinivas, Ponasanapalli Tirumala Venkata Ankayya,Bhavani, Sallagundla,Rambabu, Dandela,Rao, Mandava Venkata Basaveswara,Kapavarapu, Ravikumar,Pal, Manojit
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p. 457 - 465
(2015/06/22)
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- Yttrium-catalyzed heterocyclic formation via aerobic oxygenation: A green approach to benzothiazoles
-
The YCl3-catalyzed aerobic oxidative cyclization reaction for the synthesis of benzothiazoles has been developed. This method provides a practical, effective and green synthetic approach to benzothiazoles which are important units in many biologically active compounds.
- Fan, Li-Yan,Shang, Ying-Hui,Li, Xiang-Xiong,Hua, Wen-Jun
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supporting information
p. 77 - 80
(2015/01/30)
-
- Quaternary ammonium salt as alkylation agent in three-component reactions for the synthesis of benzothiazoles in water
-
Substituted benzothiazoles are synthesized by metal-catalyst-free three-component reactions of o-iodoaniline, quaternary ammonium salt, and sulfur powder in water with moderate-to-excellent yields up to 95%. This journal is the Partner Organisations 2014.
- Pan, Lei,Yu, Lintao,Wu, Zhiqing,Li, Zhengkai,Xiang, Haifeng,Zhou, Xiangge
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p. 27775 - 27779
(2014/07/21)
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- Room-temperature ligand-free Pd/C-catalyzed C-S bond formation: Synthesis of 2-substituted benzothiazoles
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The synthesis of 2-substituted benzothiazoles has been achieved via cyclization of o-iodothiobenzanilide derivatives using Pd/C as the catalyst at room temperature. The protocol is ligand-free, additive-free, and high-yielding and involves very mild conditions.
- Cheng, Yannan,Peng, Qian,Fan, Weigang,Li, Pixu
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p. 5812 - 5819
(2014/07/08)
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- Magnetically recoverable and reusable CuFe2O4 nanoparticle-catalyzed synthesis of benzoxazoles, benzothiazoles and benzimidazoles using dioxygen as oxidant
-
A green and efficient strategy for the synthesis of benzoxazoles, benzothiazoles and benzimidazoles has been developed by using inexpensive, readily available, dioxygen-stable and recyclable CuFe2O4 as the nanocatalyst, and o-substituted aminobenzene and various aldehydes as the starting materials. The CuFe2O4 nanoparticles are dioxygen insensitive and easily recoverable with an external magnet from the reaction medium. The catalyst can be reused ten times without significant loss of catalytic activity. This journal is the Partner Organisations 2014.
- Yang, Daoshan,Zhu, Xiao,Wei, Wei,Sun, Nana,Yuan, Li,Jiang, Min,You, Jinmao,Wang, Hua
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p. 17832 - 17839
(2014/05/06)
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- An efficient and environmental benign synthesis of 2-benzimidazoles and 2-benzothiazoles using CeCl3-NaI as catalyst
-
A one-pot condensation of an aldehyde with 1,2-phenylenediamine or 2-aminothiophenol in dimethyl carbonate at 100°C under O2 in the presence of catalytic amounts of CeCl3-NaI gave an imine intermediate, which cyclised and dehydrogenated to give 2-arylbenzimidazoles or 2-arylbenzothiazoles in good yields.
- Zhu, Xun,Wei, Yunyang
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p. 119 - 121
(2013/04/23)
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- Samarium(III) triflate as an efficient and reusable catalyst for facile synthesis of benzoxazoles and benzothiazoles in aqueous medium
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A simple, green, and efficient method is presented for the synthesis of benzoxazoles and benzothiazoles from reaction of o-aminophenols, o-aminothiophenols, and aliphatic or aromatic aldehydes using samarium triflate as a reusable acid catalyst under mild reaction conditions in aqueous medium. Georg Thieme Verlag Stuttgart, New York.
- Gorepatil, Pratapsinha B.,Mane, Yogesh D.,Ingle, Vilas S.
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p. 2241 - 2244
(2013/11/06)
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- Na2S2O4-mediated cyclocondensations of 2,2′-disulfanediyldi- anilines with aldehydes: A facile and inexpensive method for the synthesis of 2-substituted benzothiazoles
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A facile and inexpensive method for the synthesis of 2-substituted benzothiazoles has been developed by Na2S2O 4-mediated cyclocondensations of 2,2′-disulfanediyldianilines with aldehydes. In the presence of Na2S2O4 and 4 A molecular sieves, a variety of 2-substituted benzothiazoles were obtained from the reaction of 2,2′-disulfanediyldianilines with aldehydes in moderate to high yields. Copyright
- Wang, Zhanglin,Tang, Riyuan,Xiao, Qin
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experimental part
p. 314 - 320
(2012/01/05)
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- Synthesis of heteroaryl ketones via tandem reaction of 1,1-dibromoethenes
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A novel method for the synthesis of heteroaryl ketones through one-pot tandem reaction of 1,1-dibromoethenes with 2-amino(thio)phenols promoted by TBAF·3H2O and RuCl3(5%)/air was developed. This novel method includes several reactions in one-pot and utilizes economical yet efficient reagents to generate synthetically and biologically interesting heteroaryl ketones under mild conditions with good efficiency.
- Fan, Xuesen,He, Yan,Zhang, Xinying,Guo, Shenghai,Wang, Yangyang
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experimental part
p. 6369 - 6374
(2011/09/12)
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- TBHP-mediated oxidative thiolation of an sp3 C-H bond adjacent to a nitrogen atom in an amide
-
The first example of molecular sieve-promoted TBHP-mediated direct oxidative thiolation of an sp3 C-H bond adjacent to a nitrogen atom with disulfides under metal-free conditions, which allows for preparation of numerous S,N-containing compounds, is presented. Moreover, diverse benzothiazoles and a fipronil analog can be synthesized through this strategy.
- Tang, Ri-Yuan,Xie, Ye-Xiang,Xie, Yi-Li,Xiang, Jian-Nan,Li, Jin-Heng
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supporting information; experimental part
p. 12867 - 12869
(2012/02/03)
-
- Mesoporous mixed metal oxide nanocrystals: Efficient and recyclable heterogeneous catalysts for the synthesis of 1,2-disubstituted benzimidazoles and 2-substituted benzothiazoles
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Present communication elicits the use of mesoporous mixed metal oxide nanocrystals of Al2O3-Fe2O3, Al 2O3-V2O5 and Al2O 3-CuO as heterogeneous ca
- Bandyopadhyay, Prabal,Sathe, Manisha,Prasad,Sharma, Pratibha,Kaushik
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scheme or table
p. 77 - 82
(2011/06/24)
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- Ru(III)-catalyzed oxidative reaction in ionic liquid: An efficient and practical route to 2-substituted benzothiazoles and their hybrids with pyrimidine nucleoside
-
An efficient, practical and environmentally benign synthesis of 2-substituted benzothiazoles was developed through RuCl3-catalyzed oxidative condensation of 2-aminothiophenol with aldehyde in ionic liquid by using air as the oxidant. With this procedure, a series of 2-substituted benzothiazoles and benzothiazole/pyrimidine nucleoside hybrids with antimicrobial activities were efficiently prepared from easily accessible starting materials.
- Fan, Xuesen,Wang, Yangyang,He, Yan,Zhang, Xinying,Wang, Jianji
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experimental part
p. 3493 - 3496
(2010/08/20)
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- H2O2/Fe(NO3)3-promoted synthesis of 2-arylbenzimidazoles and 2-arylbenzothiazoles
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A new, convenient synthesis of 2-substituted benzimidazoles and benzothiazoles is described. Short reaction time, easy and quick isolation of the products, environmentally friendly procedure, excellent chemoselectivity and excellent yields are main advantages of this procedure. Georg Thieme Verlag Stuttgart.
- Bahrami, Kiumars,Khodaei, Mohammad Mehdi,Naali, Fardin
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body text
p. 569 - 572
(2009/06/25)
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- Zirconium(IV) oxide chloride and anhydrous copper(II) sulfate mediated synthesis of 2-substituted benzothiazoles
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A simple, fast and efficient benign procedure has been developed for one-pot synthesis of 2-substituted benzothiazoles in the presence of zirconium(IV) oxide chloride octahydrate (ZrOCl2·8H 2O) and anhydrous copper(II) sulfate. The reaction of 2-aminothiophenol with aldehydes and anhydrides was carried out efficiently in solvent-free conditions with or without microwave irradiation, and adducts were produced in good to excellent yields.
- Moghaddam, Firouz Matloubi,Ismaili, Hossein,Bardajee, Ghasem Rezanejade
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p. 136 - 141
(2007/10/03)
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- A simple iodine-promoted synthesis of 2-substituted benzothiazoles by condensation of aldehydes with 2-aminothiophenol
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Iodine is used to promote the condensation of 2-aminothiophenol with aldehydes in DMF, which affords corresponding 2-substituted benzothiazoles efficiently. Mild and manipulable procedure, use of available and less toxic oxidant, and shorter reaction times are the advantageous features of this method. Copyright
- Li, Yan,Wang, Yu-Lu,Wang, Jin-Ye
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p. 460 - 461
(2007/10/03)
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- Solvent-free synthesis of 2-aryl and 2-alkylbenzothiazoles on silica gel under microwave irradiation
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2-Substituted benzothiazoles have been synthesized by the condensation of o-aminothiophenol and aromatic or aliphatic aldehydes in the presence of silica gel under microwave irradiation (MW) and solvent-free conditions. The silica gel can be easily recovered and reused for subsequent reactions without loss of the activity.
- Kodomari, Mitsuo,Tamaru, Yoshimi,Aoyama, Tadashi
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p. 3029 - 3036
(2007/10/03)
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- Synthesis and insecticidal activity of some benzimidazolic and benzothiazolic derivatives
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The benzimidazolic and benzothiazolic derivatives with a (CH2)n radical in 2 position of the heterocycle had been synthesized and then tested for their insecticidal activity on Culex pipiens larvae. The benzothiazolic derivatives were found to be the most active. The study has also showed that this activity was related to the nature of the substitute in 2 position of the heterocycle. This activity increased when (CH2)n chain increased until n = 6; above this value, the activity decreased.
- Lahlou, M.,Weliou, M.,Salem, M.,Hajji, M. S.
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- Conversion of bis(o-nitrophenyl)disulfides to heterocycles containing sulfur and nitrogen by the action of samarium diiodide
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Treatment of bis(o-nitrophenyl)disulfides 1 with SmI2 led to simultaneous reduction of nitro groups and reductive cleavage of S-S bonds as well as the formation of the active intermediates 2. The intermediates 2 reacted smoothly with aldehydes
- Zhong, Weihui,Chen, Xiaoyuan,Zhang, Yongmin
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p. 156 - 160
(2007/10/03)
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- Low-valent titanium induced simultaneous reduction of nitro group and S-S bond in nitrodisulfides: A novel method for the synthesis of benzothiazoline, benzothiazoles and 2,3-dihydro-1,5-benzothiazepines
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The simultaneous reduction of nitro group and S-S bond in nitrodisulfides by TiCl4/Sm system leds to the active intermediates 2, which were 'living' double-anions (nitride anions and sulfide anions) in situ. These new anion species reacted smoothly with aldehydes or ketones, acid chlorides or acid anhydrides and α,β-unsaturated ketones respectively to afford the desired benzothiazolines, benzothiazoles and 2,3-dihydro-1,5-benzothiazepines in good yields under mild and neutral conditions.
- Zhong,Chen,Zhang
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p. 4451 - 4460
(2007/10/03)
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- On the reaction of silylperoxides with carbanions
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Silylperoxides 1a-f react with organolithiums 2,5,9 and 11 giving alkylation products, silylethers or silanes depending upon substitution on the silicon. A hypervalent silicon intermediate is proposed.
- Florio,Troisi
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p. 3141 - 3144
(2007/10/02)
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- ALKYLATION OF HETEROARYL ALKYL METALS BY BISTRIALKYLSILYLPEROXIDES
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Heteroaryl alkyl metals 3 undergo methylation and ethylation upon treatment with bistrimethylsilylperoxide 1a and bistriethylsilylperoxide 1b.Benzothiazolylderivatives 3c-d and 3h-j react with 1a giving trimethylsilyloxylation other than methylation products.The reaction of 3a-b with 1a leads also to the trimethylsilylation product 5.The reaction of 3g, 3c and 3k with 1b provides the ethylated derivatives 2h, 2d and 2n respectively.No reaction occurred when 3c was treated with 1c.
- Epifani, Erbana,Florio, Saverio,Troisi, Luigino
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p. 4031 - 4038
(2007/10/02)
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- SELF-CONDENSATION REACTION OF ALKYLBENZOTHIAZOLES WITH GRIGNARD REAGENTS
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2-alkylbenzothiazoles undergo Claisen-type self-condensation reaction simply on treatment with Grignard reagents.
- Babudri, F.,Ciminale, F.,Florio, S.
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p. 2051 - 2054
(2007/10/02)
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