- Method for preparing 1, 3-benzothiazole derivative through efficient catalysis of potassium tert-butoxide
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The invention discloses a method for preparing 1, 3-benzothiazole derivative through efficient catalysis of potassium tert-butoxide. According to the method, a 1-phenyl-3-butyne-2-ketone compound andan o-aminothiophenol compound are taken as raw materials, potassium tert-butoxide is taken as a catalyst and tert-butyl alcohol is taken as a solvent to prepare the 1, 3-benzothiazole derivative at high efficiency and high yield. According to the method, no metal catalyst is used, the method is environmentally friendly, reaction conditions are mild, operation is easy, the 1, 3-benzothiazole derivative can be obtained only by conducting simple column chromatography separation on a product obtained after the reaction is finished, a new green and efficient way is developed for preparation of the1, 3-benzothiazole derivative, and certain application prospects are achieved.
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Paragraph 0007; 0014-0019; 0034-0037
(2020/02/10)
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- Straightforward synthesis of benzoxazoles and benzothiazoles via photocatalytic radical cyclization of 2-substituted anilines with aldehydes
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Eosin Y-catalyzed one-pot coupling and cyclization of o-substituted anilines with aldehydes to form benzoxazoles and benzothiazoles under mild condition has been developed. The reaction scope was broadly tolerant of various 2-substituted anilines and aldehydes. The desired products were obtained in high yields with the use of eosin Y as a photocatalyst under a substantial refinement of reaction conditions in comparison with previous literature. Based on the experimental results observed, a plausible mechanism involving a radical process has been proposed.
- Le, Hao Anh Nguyen,Nguyen, Long Hoang,Nguyen, Quynh Nhu Ba,Nguyen, Hai Truong,Nguyen, Khang Quoc,Tran, Phuong Hoang
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- An efficient synthesis of benzothiazole using tetrabromomethane as a halogen bond donor catalyst
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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)
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- Di- tert-butyl Peroxide-Mediated Radical C(sp2/sp3)-S Bond Cleavage and Group-Transfer Cyclization
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A novel strategy of cascade radical C(sp2/sp3)-S bond cleavage and group-transfer cyclization is disclosed. Triggered by alkyl radicals, varieties of 2-isocyanoaryl thioethers containing aliphatic, aryl, and heteroaromatic groups can be cleaved and precisely reinstalled to give benzothiazole derivatives. Mechanistic studies reveal that the cascade reaction undertakes an intermolecular pathway, and the inner radical sources (R radicals) exhibit high priority over those of methyl radical origin from di-tert-butyl peroxide.
- Luo, Kai,Yang, Wen-Chao,Wei, Kai,Liu, Yue,Wang, Jun-Ke,Wu, Lei
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p. 7851 - 7856
(2019/10/11)
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- Ni-Catalyzed Reductive Liebeskind-Srogl Alkylation of Heterocycles
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Herein we present a Ni-catalyzed alkylation of C-SMe with alkyl bromides for the decoration of heterocyclic frameworks. The protocol, reminiscent to the Liebeskind-Srogl coupling, makes use of simple C(sp2)-SMe to be engaged in a reductive coupling. The reaction is suitable for a preponderance of highly valuable heterocyclic motifs. In addition to cyclic bromides, noncyclic alkyl bromides are well accommodated with exquisite levels of retention over isomerization. The protocol is scalable and permits orthogonal couplings in the presence of other functionalization handles.
- Ma, Yuanhong,Cammarata, Jose,Cornella, Josep
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supporting information
p. 1918 - 1922
(2019/02/14)
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- Controllable assembly of the benzothiazole framework using a CC triple bond as a one-carbon synthon
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A concise and efficient protocol to assemble diverse benzothiazole derivatives in high yields was provided via copper catalyzed tandem cyclization with o-haloanilines, elemental sulfur and terminal alkynes as raw materials. In this protocol, C atoms on the CC triple bond were controllably involved in the construction of the benzothiazole framework and multiple carbon-heteroatom bonds through divergent routes.
- Huang, Yubing,Yan, Donghao,Wang, Xu,Zhou, Peiqi,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 1742 - 1745
(2018/02/21)
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- A simple and efficient route for synthesis of 2-alkylbenzothiazoles
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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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- Synthesis of Quinoline-Based NNN-Pincer Nickel(II) Complexes: A Robust and Improved Catalyst System for C-H Bond Alkylation of Azoles with Alkyl Halides
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The quinoline-based pincer nickel(II) complexes κN,κN,κN-{R2N-C6H4-(μ-N)-C9H6N}NiX ((R2NNNQ)NiCl: R = Me, 2a; R = Et, 2b) were synthesized by the reaction of the ligand precursors (R2NNNQ)H (R = Me, 1a; R = Et, 1b) with (DME)NiCl2 in the presence of Et3N. Similarly, the pincer nickel(II) derivatives (R2NNNQ)NiX (R = Me, X = Br, 3a; R = Et, X = Br, 3b; R = Me, X = OAc, 4a) were obtained by treatment of the ligands (R2NNNQ)H with the nickel precursor (THF)2NiBr2 or Ni(OAc)2. All of these complexes were characterized by 1H and 13C NMR spectroscopy as well as by elemental analysis. Further, the molecular structures of 2a and 3a,b were elucidated by X-ray crystallography. Complex 2a is found to be an efficient catalyst for the direct C-H bond alkylation of substituted benzothiazoles and oxazoles with various unactivated alkyl halides containing β-hydrogens under mild reaction conditions. The catalyst 2a is very robust and was recycled and reused five times for the alkylation reaction without a decrease in its catalytic activity. Preliminary studies reveal that the catalyst 2a acts as an active catalyst and the alkylation reaction appears to operate via a radical pathway.
- Patel, Ulhas N.,Pandey, Dilip K.,Gonnade, Rajesh G.,Punji, Benudhar
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supporting information
p. 1785 - 1793
(2016/07/06)
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- Quaternary ammonium salt as alkylation agent in three-component reactions for the synthesis of benzothiazoles in water
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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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- Synthesis of 2-Acylbenzothiazoles via the Cu(OTf)2-Catalyzed tandem reaction of β,β-Dihalidestyrenes with 2,2′- Disulfanediyldianilines
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A new method has been developed for the one-pot construction of 2-acylbenzothiazoles via the Cu(OTf)2-catalyzed tandem reaction of β,β-dihalidestyrenes with 2,2′-disulfane-diyldianilines. A variety of different dihalidestyrenes and diphenyldisulfanes were efficiently converted into the corresponding 2-acylbenzothiszole derivatives in the presence of Cu(OTf)2. Most importantly, this protocol allowed for the long chain 1,1-dibromohept-1-ene to be converted into the corresponding 2-hexylbenzo[d]thiazole in moderate yield. Georg Thieme Verlag Stuttgart, New York.
- Zhou, Zeng-Le,Fang, Tao,Tang, Ri-Yuan,Zhang, Xing-Guo,Deng, Chen-Liang
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supporting information
p. 255 - 260
(2014/02/14)
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- Cyanide as a powerful catalyst for facile synthesis of benzofused heteroaromatic compounds via aerobic oxidation
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Highly efficient synthesis of benzofused heteroaromatic compounds via aerobic oxidation catalyzed by cyanide anion has been developed. The Schiff bases derived from 2-aminophenol and aldehydes provided the corresponding benzoxazoles in high yields in the presence of a catalytic amount of cyanide in an open flask under ambient conditions without the use of any external metal co-oxidants and bases. Furthermore, we have developed a catalytic sequential one-step protocol for the synthesis of benzoxazoles by adding a catalytic amount of NaCN to Schiff bases generated in situ from 2-aminophenol and aldehydes without the isolation of imine intermediates. This one-pot protocol was further extended to the synthesis of benzothiazoles from 2-aminothiophenol and aldehydes. A variety of aldehydes could be applied to this sequential one-pot protocol and the desired benzofused azole products were obtained in high yields.
- Cho, Yeon-Ho,Lee, Chun-Young,Cheon, Cheol-Hong
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p. 6565 - 6573
(2013/07/26)
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- Synthesis of 2-substituted benzothiazoles from 1-iodo-2-nitrobenzenes by a copper-catalyzed one-pot three-component reaction
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A novel method was developed for synthesizing 2-substituted 1,3-benzothiazoles through a copper-catalyzed, one-pot, three-component reaction of a 1-iodo-2-nitrobenzene with sodium sulfide and an aldehyde. Georg Thieme Verlag Stuttgart - New York.
- Liu, Jidan,Gui, Qingwen,Yang, Zhiyong,Tan, Ze,Guo, Ruqing,Shi, Ji-Cheng
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p. 943 - 951
(2013/05/08)
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- Synthesis of 2-aryl benzothiazoles via K2S2O 8-mediated oxidative condensation of benzothiazoles with aryl aldehydes
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Nontransition metal-catalyzed synthesis of 2-aryl benzothiazoles was achieved through K2S2O8-mediated oxidative condensation of benzothiazoles with aryl aldehydes. The same transformation can also be effected when the aryl
- Yang, Zhiyong,Chen, Xiang,Wang, Sizhuo,Liu, Jidan,Xie, Kai,Wang, Anwei,Tan, Ze
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experimental part
p. 7086 - 7091
(2012/10/18)
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- User-friendly [(diglyme)NiBr2]-catalyzed direct alkylations of heteroarenes with unactivated alkyl halides through C-H bond cleavages
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A nitrogen and phosphorus ligand-free catalytic system derived from inexpensive [(diglyme)NiBr2] allowed for efficient direct C-H bond alkylations of heteroarenes with unactivated β-hydrogen-containing alkyl halides under basic reaction conditi
- Ackermann, Lutz,Punji, Benudhar,Song, Weifeng
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supporting information; experimental part
p. 3325 - 3329
(2012/01/19)
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- 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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- Palladium- and nickel-catalyzed direct alkylation of azoles with unactivated alkyl bromides and chlorides
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Long-ing alkyl chain: The catalytic direct C-H alkylation of azoles with unactivated alkyl bromides and chlorides is described. A palladium catalyst enables the alkylation of oxazoles, whereas a nickel one shows unique activity for thiazole. The catalyses allow a straightforward access to azole motifs bearing long, functional alkyl side chains.
- Yao, Tomoyuki,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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supporting information; experimental part
p. 12307 - 12311
(2011/02/16)
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- Lawesson's reagent and microwaves: A new efficient access to benzoxazoles and benzothiazoles from carboxylic acids under solvent-free conditions
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Lawesson's reagent acts as an efficient promoter in the solvent-free microwave-assisted synthesis of 2-substituted benzoxazoles from carboxylic acids and 2-aminophenol, and thus, constitutes a general synthetic method for these compounds. This new application of Lawesson's reagent is valid also for benzothiazoles with very high efficiency level. A variety of aromatic, heteroaromatic and aliphatic carboxylic acids react under the conditions developed with good yields in all cases. Thiobenzoic acid is a good alternative for microwave-assisted synthesis of 2-phenylbenzoxazole and 2- phenylbenzothiazole in the absence of solvents. Georg Thieme Verlag Stuttgart.
- Seijas, Julio A.,Vázquez-Tato, M. Pilar,Carballido-Reboredo, M. Raquel,Crecente-Campo, José,Romar-López, Lucía
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p. 313 - 317
(2007/10/03)
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- Intermolecular coupling of alkenes to heterocycles via C-H bond activation
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The intermolecular coupling of unactivated alkenes to a range of heterocycles using a Rh(I) catalyst was investigated. A variety of functional groups were incorporated into the alkene, including esters, nitriles, acetals, and phthalimide. Furthermore, the heterocycle tolerated substitution with both electron-rich and electron-deficient groups. The intermolecular coupling became possible after it was discovered that weak acids dramatically increase the rate of both the inter- and intramolecular reactions. An extensive optimization of additives was performed, and HCl·PCy3 (Cy = cyclohexyl) and HCl·P-t-Bu2Et were in general found to be the best additives for the reaction.
- Tan, Kian L.,Park, Steve,Ellman, Jonathan A.,Bergman, Robert G.
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p. 7329 - 7335
(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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- Solid phase synthesis of benzothiazolyl compounds
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2-Aminobenzenethiol, bound through its thiol function to the 2-chlorotrityl (Clt)-, trityl (Trt)-, 4-methyltrityl (Mtt)- and 4-methoxytrityl (Mmt)-resins, was acylated at the amino-function by aliphatic and aromatic acids. The obtained 2-N-acyl-aminobenzenethiols were cleaved from the resin by treatment with trifluoroacetic acid solutions in dichloromethane. The 2-N-acyl-aminobenzenethiols released from the resin were cyclised to the corresponding 2-substituted benzothiazoles, by standing in a solution of dithiothreitol in DMF or methanol for 1-3 h at room temperature.
- Mourtas, Spyros,Gatos, Dimitrios,Barlos, Kleomenis
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p. 2201 - 2204
(2007/10/03)
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