- A simple, microwave-assisted, and solvent-free synthesis of 2-arylbenzothiazoles by acetic acid-promoted condensation of aldehydes with 2-aminothiophenol in air
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An efficient and simple procedure has been developed for the synthesis of various 2-arylbenzothiazoles by acetic acid-promoted condensation of 2 -aminothiophenol with aromatic aldehydes under microwave irradiation and solvent-free conditions in high yield
- Azarifar, Davood,Maleki, Behrooz,Setayeshnazar, Mehrnaz
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- 1,3-dibromo-5,5-dimethylhydantoin catalyzed one-pot synthesis of 2-arylbenzothiazoles
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A one-pot synthesis of 2-arylbenzothiazoles from the reaction of 2-aminothiophenol and aromatic aldehydes catalyzed by 1,3-dibromo-5,5- dimethylhydantoin is reported.
- Yang, Xiaojuan,Liang, Jinying
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- Sulfonated porous Carbon (SPC)-catalyzed synthesis of benzothiazole derivatives in water
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A simple and efficient procedure has been developed for the synthesis of benzothiazole derivatives in water by the condensation of 2-aminothiophenol with aldehydes in the presence of Sulfonated porous carbon (SPC). This method provides a simple and effici
- Shokrolahi, Arash,Zali, Abbas,Mahdavi, Mohammd
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- New synthesis method of 2-arylbenzothiazoles transfer of active electrons by microwave
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The condensation of several aldehydes wtih 2-aminothiophenol on silica gel/nitrobenzene or montmorillonite K10/nitrobenzene under microwave irradiation afforded 2-arylbenzothiazoles in good yields and high purity.
- Ben-Alloum, Abdelkrim,Bakkas, Salem,Soufiaoui, Mohamed
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- An efficient green synthesis of 2-arylbenzothiazole analogues as potent antibacterial and anticancer agents
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We have demonstrated a novel and green approach for the synthesis of 2-substituted benzothiazole analogues. A number of 2-aryl and heteroaryl benzothiazole scaffolds were synthesized using Amberlite IR-120 resin under microwave irradiation. The catalytic
- Chhabra, Mohit,Sinha, Sohini,Banerjee, Swagata,Paira, Priyankar
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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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- ZnO-beta zeolite: As an effective and eco-friendly heterogeneous catalyst for the synthesis of benzothiazole derivatives
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A cheap and recyclable ZnO-beta zeolite was used as catalyst for the synthesis of benzothiazole derivatives. This method provides several advantages such as environmental friendliness, short reaction times, high yields, simple work-up procedure and cataly
- Katkar, Santosh S.,Mohite, Pravinkumar H.,Gadekar, Lakshman S.,Vidhate, Kaluram N.,Lande, Machhindra K.
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- A simple and efficient synthesis of (hetero)aryl-substituted benzothiazolyl or benzoxazolyl furan, thiophene and N -methylpyrrole derivatives through a palladium-catalyzed regioselective C-H bond arylation
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The synthesis of 2-(hetero)aryl-5-benzothiazol-2-yl or -benzoxazol-2-ylfuran, -thiophene, and -1-methylpyrrole derivatives was accomplished in two steps. 2-(Benzothiazol-2-yl)- or 2-benzoxazol-2-ylfuran, -thiophene, or -1-methylpyrrole were synthesized by
- Abdellaoui, Fatma,Youssef, Chiraz,Ben Ammar, Hamed,Soul, Jean-Franois,Doucet, Henri
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- Synthesis of 2-arylbenzimidazoles and 2-arylbenzothiazoles in both room temperature and microwave condition catalyzed by hexamethylenetetramine-bromine complex
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One-pot condensation of 2-aminothiophenol or 1,2-phenylenediamine with different aldehydes has been catalyzed by hexamethylenetetramine-bromine (HMTA-Bromine) as new, available and effective catalyst. 2-Arylbenzo-thiazoles and 2-aryl-benzimidazoles have b
- Khosravi, Kaveh,Kazemi, Samira
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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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- P2O5 mediated rapid condensation of 2-aminothiophenol with aromatic aldehydes at ambient temperature
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2-Arylbenzothiazoles formed in good yields (65-90%) by the condensation of aminothiophenols with aromatic aldehydes using P2O5 at ambient temperature.
- Nalage, Santosh V.,Bhosale, Sidhanath V.,Bhosale, Dattatry S.,Jadhav, Wamanrao N.
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- Recyclable copper-catalyzed cyclization of o-haloanilides and metal sulfides: An efficient and practical access to substituted benzothiazoles
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An efficient heterogeneous copper-catalyzed cyclization of o-haloanilides and metal sulfides has been achieved via the C–S coupling in DMF at 80 or 140 °C in the existence of an MCM-41-bound NHC-Cu(I) catalyst and then intramolecular condensation, delivering a wide range of substituted benzothiazoles in mostly good to high yields. This new MCM-41-NHC-CuI complex can facilely be obtained by a two-step procedure starting from easily accessible and inexpensive reagents and reused more than seven times without any significant loss of its catalytic efficiency. The present protocol has been successfully applied to the gram-scale synthesis of two antitumor agents 5F203 and PMX 610.
- Cai, Mingzhong,Hao, Wenyan,Huang, Wencheng,Ye, Qian
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- Ultrasound-assisted efficient and green synthesis of 2-substituted benzothiazoles under solvent-free condition using recyclable sulfated tungstate
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Sulfated tungstate catalyzed an efficient and ecofriendly protocol has been described for the synthesis of 2-substituted benzothiazoles. The corresponding benzothiazoles were obtained using a condensation reaction of 2-aminothiophenol with various aldehydes under ultrasound irradiation at room temperature. Various functional groups on the 2-aminothiophenol as well as on the aldehydes were tolerated to provide 2-substituted benzothiazoles derivatives in excellent yields. The faster reaction rate, solvent-free or mild reaction conditions, wide functional group compatibility, excellent yields, easy work-up procedure, and excellent catalyst recyclability are the advantages of this protocol. These advantages make this process more practicable, cost-effective, and environmentally benign.
- Pise, Ashok S.,Ingale, Ajit P.,Dalvi, Navnath R.
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supporting information
p. 3629 - 3641
(2021/10/12)
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- Fluorinated phosphoric acid as a versatile effective catalyst for synthesis of series of benzimidazoles, benzoxazoles and benzothiazoles at room temperature
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The present work describes synthesis of a series of benzimidazoles, benzoxazoles and benzothiazoles through the cyclization of 1, 2-phenylenediamine, 2-aminothiophenol, or 2-aminophenol with aryl, aliphatic and heteroaryl aldehydes. The present synthetic protocol is very much efficient in presence of 5 mol % fluorophosphoric acid as a catalyst in ethanol solvent at room temperature. Shorter reaction time, simple work-up technique, high yields and easy availability are specific compensations of the present synthetic approach.
- Mathapati, Sushil R.,Patil, Komal N.,Mathakari, Sujit S.,Suryawanshi, Appasaheb W.,Jadhav, Arvind H.
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p. 538 - 547
(2021/01/21)
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- Pentafluorophenylammonium Triflate: A Mild, Efficient and Reusable Catalyst for the Synthesis of 2-Arylbenzothiazole and 2-Arylbenzothiazoline Derivatives in a Green Chemical Approach
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In this work, one pot, simple and environmentally benign effective synthesis of 2-substituted benzothiazole and benzothiazoline derivatives are described in presence of PFPAT (pentafluorophenylammonium triflate) catalyst in water successfully. A series of benzothiazole derivative were synthesized by the reaction between 2-aminothiophenol and various aldehydes in good yields. Recyclability of the catalyst is observed for four times without loss of its activity in aqueous medium.
- Datta, Arup
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- Ionic-Liquid-Catalyzed Synthesis of Imines, Benzimidazoles, Benzothiazoles, Quinoxalines and Quinolines through C?N, C?S, and C?C Bond Formation
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We report the tetramethyl ammonium hydroxide catalyzed oxidative coupling of amines and alcohols for the synthesis of imines under metal-free conditions by utilizing oxygen from air as the terminal oxidant. Under the same conditions, with ortho-phenylene diamines and 2-aminobenzenethiols the corresponding benzimidazoles and benzothiazoles were obtained. Quinoxalines were obtained from ortho-phenylene diamines and 1-phenylethane-1,2-diol, the conditions were then extended to the synthesis of quinoline building blocks by reaction of 2-amino benzyl alcohols either with 1-phenylethan-1-ol or acetophenone derivatives. The formation of C?N, C?S and C?C bonds was achieved under metal-free conditions. A broad range of amines (aromatic, aliphatic, cyclic and heteroaromatic) as well as benzylic alcohols including heteroaryl alcohols reacted smoothly and provided the desired products. The mild reaction conditions, commercially available catalyst, metal-free, good functional-group tolerance, broad range of products (imines, benzimidazoles, benzothiazoles, quinoxalines and quinolines) and applicability at gram scale reactions are the advantages of the present strategy.
- Adimurthy, Subbarayappa,Badhani, Gaurav,Joshi, Abhisek
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p. 6705 - 6716
(2021/12/31)
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- Photocatalyst- And Transition-Metal-Free Visible-Light-Promoted Intramolecular C(sp2)-S Formation
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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
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p. 2078 - 2083
(2021/04/05)
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- ZnO-NPs catalyzed condensation of 2-aminothiophenol and aryl/alkyl nitriles: Efficient green synthesis of 2-substituted benzothiazoles
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The synthesis of 2-substituted benzothiazoles has been described using ZnO-nanoparticles as a catalyst. The condensation of 2-aminothiophenol and aryl/alkyl nitriles resulted in the formation of various 2-substituted benzothiazoles under solvent-free reaction conditions. The library of 2-substituted benzothiazoles has been synthesized in good to excellent yield. The reaction has shown a wide range of functional group compatibility for both varyingly substituted 2-aminothiophenols and nitriles. The protocol has many advantages such as faster reaction rate, mild reaction conditions, various functional group compatibility, excellent yield, solvent-free reaction conditions, easy recovery of materials, and excellent catalyst recyclability, among others. The various advantages of this protocol make it a more feasible, economical, and environmentally benign process.
- Dhawale, Kiran D.,Ingale, Ajit P.,Shinde, Sandeep V.,Thorat, Nitin M.,Patil, Limbraj R.
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p. 1588 - 1601
(2021/03/18)
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- Method for preparing benzothiazole compound from visible light promoted N-(2-bromophenyl) thioamide
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The invention discloses a method for preparing a benzothiazole compound from N-(2-bromophenyl) thioamide under the promotion of visible light. Specifically, under the protection of inert gas, according to the molar ratio of N-(2-bromophenyl) thioamide to inorganic base being 1: 0.5, reactants are added into a reaction container provided with a stirring device, then dimethyl sulfoxide is added, and stirring reaction is carried out for 2-24 hours at room temperature under the irradiation of visible light to obtain the benzothiazole compound. 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) thioamide are realized. In addition, the benzothiazole compound 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 benzothiazole compound.
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Paragraph 0115-0117
(2021/06/22)
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- Preparation method of 2-aryl benzothiazole compound
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The invention discloses a preparation method of a 2-arylbenzothiazole compound, which comprises the following steps: adding a reaction substrate 2-aminothiophenol and ketonic acid(or aldehyde) into adeep eutectic solvent, magnetically stirring in an oil bath pot at 60-90 DEG C, and carrying out after-treatment after the reaction is finished to obtain the 2-arylbenzothiazole compound, wherein a deep eutectic solvent is a reaction solvent, and other catalysts are not needed. The method is simple to operate, mild in reaction condition, efficient in reaction, high in atom economy, few in byproducts and green and environment-friendly in reaction process, and has popularization and application values.
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Paragraph 0116; 0119-0121
(2020/05/09)
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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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- Oxidative NHC catalysis for base-free synthesis of benzoxazinones and benzoazoles by thermal activated NHCs precursor ionic liquid catalyst using air as oxidant
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A reusable thermal activated NHC precursor ionic liquid catalyst ([BMIm]2[WO4]) has been prepared and developed for the synthesis of nitrogen-containing heterocycles such as benzoxazinones and benzoazoles through imines activation. [BMIm]2[WO4] exhibited the good activity for the base-free condensation and oxidative NHC catalysis tandem under air atmosphere. The catalyst can be recovered and reused for at least five runs in gram scale synthesis without any decrease in catalytic activity. Furthermore, the control experiments demonstrated that the reaction involved formation of aromatic aldimines, NHC-catalyzed oxidative formation of imidoyl azoliums and intramolecular cyclization to generate the product.
- Guan, Jiali,Liu, Wei,Liu, Yuchen,Song, Zhibin,Tao, Duan-Jian,Yan, Jieying,Yuan, Jian-Jun,Zhou, Youkang
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- A novel ternary GO@SiO2-HPW nanocomposite as an efficient heterogeneous catalyst for the synthesis of benzazoles in aqueous media
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A new solid acid catalyst, consisting of 12-phosphotungstic heteropoly acid (HPW) supported on graphene oxide/silica nanocomposite (GO@SiO2), has been developed via immobilizing HPW onto an amine-functionalized GO/SiO2 surface through coordination interaction (GO@SiO2-HPW). The GO@SiO2-HPW nanocomposite was characterized by Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and powder X-ray diffraction (XRD). The prepared nanocomposite could be dispersed homogeneously in water and further used as a heterogeneous, reusable, and efficient catalyst for the synthesis of benzimidazoles and benzothiazoles by the reaction of 1,2-phenelynediamine or 2-aminothiophenol with different aldehydes.
- Habibzadeh, Setareh,Firouzzadeh Pasha, Ghasem,Tajbakhsh, Mahmood,Amiri Andi, Nasim,Alaee, Ehsan
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p. 934 - 944
(2019/06/13)
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- TBHP/KI-Promoted Annulation of Anilines, Ethers, and Elemental Sulfur: Access to 2-Aryl-, 2-Heteroaryl-, or 2-Alkyl-Substituted Benzothiazoles
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An efficient TBHP/KI-promoted annulation of anilines with ethers and elemental sulfur has been developed through the selective C-O bond cleavage of ethers under transition-metal-free conditions. A wide range of 2-aryl-, 2-heteroaryl-, and 2-alkyl-substituted benzothiazoles were easily prepared with satisfactory yields and good functional group compatibility.
- Zhang, Jie,Zhao, Xin,Liu, Ping,Sun, Peipei
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p. 12596 - 12605
(2019/10/11)
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- Peroxide-mediated oxidative coupling of primary alcohols and disulfides: Synthesis of 2-substituted benzothiazoles
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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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- 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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p. 389 - 399
(2019/05/06)
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- Urea nitrate catalyzed synthesis of 2-arylbenzothiazoles using the grindstone technique
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An efficient, green and environmentally friendly grindstone method for the synthesis of 2-arylbenzothiazole derivatives in the presence of urea nitrate as the catalyst under solvent-free conditions was developed. All products were characterized by elemental analysis and spectral methods.
- Gandhi, Divyani,Agarwal, Shikha
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p. 307 - 310
(2018/11/27)
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- Chitosan-SO3H: A green approach to 2-aryl/heteroaryl benzothiazoles under solvent-free conditions at room temperature
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An efficient green protocol have been developed for the synthesis of 2-aryl/heteroaryl benzothiazole derivatives by intramolecular cyclocondensation of 2-mercaptoaniline with various substituted aryl/heteroaryl aldehydes using chitosan-SO3H as an efficien
- Bathula, Surendra Bose,Khagga, Mukkanti,Venkatasubramanian, Hariharakrishnan
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p. 1512 - 1516
(2018/06/12)
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- Solid Acid Supported on Magnetic Nanoparticles as a Highly Efficient and Retrievable Catalyst for the Synthesis 2-Substituted Benzothiazoles
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The use of a recyclable heterogeneous nanomagnetic solid acid catalyst, [Fe3O4@SiO2@(CH2)3NPC–SO3H]Cl, in a simple and highly efficient synthesis of benzothiazole derivatives by the reactio
- Gorjizadeh,Sayyahi
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p. 1899 - 1903
(2018/11/24)
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- Phosphine free Mn-complex catalysed dehydrogenative C-C and C-heteroatom bond formation: A sustainable approach to synthesize quinoxaline, pyrazine, benzothiazole and quinoline derivatives
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Herein the first sustainable synthesis of quinoxalines, pyrazines and benzothiazoles catalysed by a phosphine free Mn(i) complex via acceptorless dehydrogenative coupling (ADC) is reported. This method is also applied successfully to synthesize quinolines via the dehydrogenation (removal of H2) and condensation (removal of H2O) reaction between 2-aminobenzyl alcohols and secondary alcohols.
- Das, Kalicharan,Mondal, Avijit,Srimani, Dipankar
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supporting information
p. 10582 - 10585
(2018/09/25)
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- Silver-mediated 2-arylation/alkylation/acylation of benzothiazoles with aldehydes in water
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An efficient and environmentally benign method was developed for the facile synthesis of various 2-aryl and 2-alkyl substituted benzothiazoles in moderate to good yields, using a silver-mediated redox condensation of benzothiazoles and aldehydes in water. Furthermore, this method is also applicable to prepare 2-acyl benzothiazoles.
- Hua, Min,Wang, Chunqin,Liu, Qixing,Chen, Danyi,Fu, Hao,Zhou, Haifeng
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p. 1226 - 1237
(2018/08/06)
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- Electrochemical Acceptorless Dehydrogenation of N-Heterocycles Utilizing TEMPO as Organo-Electrocatalyst
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Catalytic acceptorless dehydrogenation (CAD) has been a basically important organic transformation to ubiquitous unsaturated compounds without the usage of a sacrificial hydrogen acceptor. In this work, we successfully developed the first electrochemical acceptorless dehydrogenation (ECAD) of N-heterocycles using TEMPO as the organo-electrocatalyst. We have achieved the catalytic dehydrogenation of N-heterocycles in an anode and the release of H2 in a cathode using an undivided-cell system. A variety of six-membered and five-membered nitrogen-heteroarenes can be synthesized in good yields in this system. In addition, this protocol can also be used in the application of important molecular synthesis. Our electrochemical strategy provides a mild and metal-free route for (hetero)aromatic compounds synthesis via the CAD strategy.
- Wu, Yong,Yi, Hong,Lei, Aiwen
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p. 1192 - 1196
(2018/02/14)
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- Pd-Catalyzed Decarbonylative C?H Coupling of Azoles and Aromatic Esters
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A decarbonylative C?H coupling of azoles and aromatic esters by palladium catalysis is described. Our previously reported Ni-catalyzed C?H coupling of azoles and aromatic esters has a significant drawback regarding the substrate scope. Herein, we employ p
- Matsushita, Kaoru,Takise, Ryosuke,Hisada, Tomoya,Suzuki, Shin,Isshiki, Ryota,Itami, Kenichiro,Muto, Kei,Yamaguchi, Junichiro
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supporting information
p. 2393 - 2396
(2018/05/30)
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- Selective Construction of 2-Substituted Benzothiazoles from o-Iodoaniline Derivatives S8 and N-Tosylhydrazones
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Selective construction of 2-substituted benzothiazoles from o-iodoaniline derivatives S8 and N-tosylhydrazone via a copper-promoted [3 + 1 + 1]-type cyclization reaction has been realized. In the protocol, the carbon atom on N-tosylhydrazone could be regulated to construct benzothiazole by changing the reaction system. Furthermore, the transformation has achieved the construction of multiple carbon-heteroatom bonds.
- Huang, Yubing,Zhou, Peiqi,Wu, Wanqing,Jiang, Huanfeng
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p. 2460 - 2466
(2018/02/23)
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- Method for preparing benzothiazole compound through microwave catalysis in water phase
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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.
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Paragraph 0041
(2018/05/16)
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- Elemental Sulfur-Mediated Decarboxylative Redox Cyclization Reaction: Copper-Catalyzed Synthesis of 2-Substituted Benzothiazoles
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A S 8 -mediated directed decarboxylative redox-cyclization strategy for the synthesis of 2-substituted benzothiazoles from o -iodoanilines, arylacetic acids, and elemental sulfur catalyzed by cheap copper metal has been developed. This reaction is operationally simple, ligand-free, compatible with a wide range of functional groups, and provides the desired products in good to excellent yields. In addition, a gram-scale experiment was carried out to furnish PMX 610, an antitumor drug.
- Wang, Xin,Li, Xiaotong,Hu, Renhe,Yang, Zhao,Gu, Ren,Ding, Sai,Li, Pengyi,Han, Shiqing
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supporting information
p. 219 - 224
(2017/10/09)
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- Visible-light-promoted synthesis of benzothiazoles from 2-aminothiophenols and aldehydes
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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
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supporting information
p. 874 - 876
(2017/02/18)
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- Green and Highly Efficient Synthesis of Mono- and Bis-Benzothiazoles in the Presence of Fe(SD)3 under Ultrasound Irradiation
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A convenient, practical, green, and environmentally friendly method was developed for the synthesis of benzothiazoles from 2-aminothiophenol and various aldehydes. Bis-benzothiazoles were synthesized in high yield under mild reaction conditions. Products
- Pirbasti, Fateme Ghanbari,Mahmoodi, Nosrat Ollah
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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
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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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- Direct arylation of benzoazoles with aldehydes utilizing metal-organic framework Fe3O(BDC)3 as a recyclable heterogeneous catalyst
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A metal-organic framework Fe3O(BDC)3 was synthesized and used as a recyclable heterogeneous catalyst for the direct arylation of azoles with benzaldehydes. Following this protocol, inexpensive and commercially available benzaldehydes could act as an aryl source for the transformation, replacing the aryl halides normally employed in the conventional cross-coupling reactions. The catalyst disclosed higher catalytic productivity for the formation of aryl-substituted azoles than various MOFs and diverse homogeneous iron catalysts. The conversion was considerably regulated by the solvent and the oxidant, and the combination of N-methyl-2-pyrrolidone with di-tert-butyl peroxide offered the best yield. Heterogeneous catalysis was verified for the reaction, and the production of aryl-substituted azoles was only feasible in the presence of the iron framework. It was possible to reuse the catalyst for the direct arylation of azoles with aldehydes while its catalytic activity was preserved for multiple cycles. To our best judgment, this direct arylation of azoles with aldehydes utilizing solid catalysts has not been previously reported.
- Doan, Son H.,Nguyen, Khoa D.,Nguyen, Tung T.,Phan, Nam T. S.
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p. 1423 - 1431
(2017/01/21)
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- Elemental sulfur mediated cyclization via redox strategy: Synthesis of benzothiazoles from o-chloronitrobenzenes and benzyl chlorides
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A novel metal-free synthesis of 2-substituted benzothiazoles from easily available o-chloronitrobenzenes and benzyl chlorides using elemental sulfur as traceless oxidizing agent has been developed. The protocol provides a simple, efficient, and atom-economic way to access to benzothiazoles in moderate to excellent yields. And the approach exhibited good functional group tolerance.
- Wang, Xin,Miao, Dazhuang,Li, Xiaotong,Hu, Renhe,Yang, Zhao,Gu, Ren,Han, Shiqing
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supporting information
p. 5194 - 5199
(2017/07/28)
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- One-pot copper-catalyzed synthesis of 2-substituted benzothiazoles from 2-iodoanilines, benzyl chlorides and elemental sulfur
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An efficient one-pot three-component reaction of 2-iodoanilines, benzyl chlorides and elemental sulfur to form 2-substituted benzothiazoles in satisfactory yields (up to 98%) has been described. The reaction tolerated a wide range of functional groups on the aromatic ring. And heterocycle methylene chlorides substrates were also found to be compatible.
- Yang, Zhao,Hu, Renhe,Li, Xiaotong,Wang, Xin,Gu, Ren,Han, Shiqing
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supporting information
p. 2366 - 2369
(2017/05/29)
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- Synthesis of 2 - substituted benzothiazole derivatives
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The invention discloses a method of synthesizing a 2-substituted benzothiazole-type derivative, wherein the method includes a step of synthesizing the 2-substituted benzothiazole-type derivative with an aldehyde and a disulphide as raw materials under a combined effect of at least one from NaHCO3 and AcOH with a metal sulfide. The particular reaction is represented as follows, wherein the R comprises one or more from a hydrogen atom, a C1-C4 alkyl, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a cyan group and a nitryl group; the R' substituent group comprises at least one from a C1-C6 alkyl, a furan group, a thienyl group, a pyrryl group, a pridyl group and a substituted phenyl group. The method employs the raw material being stable and easy to obtain, and can quickly and conveniently synthesize the 2-substituted benzothiazole-type derivative at a high production yield.
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Paragraph 0112-0115
(2017/07/23)
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- Efficient synthesis of benzothiazole derivatives by reaction of bis(2-aminophenyl) disulfides with aldehydes mediated by NaSH under microwave irradiation
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2-Substituted benzothiazoles were synthesized through condensation of bis(2-aminophenyl) disulfides with arylaldehydes catalyzed by inexpensive NaSH in PEG-300 and assisted by low energy microwave irradiation(25?W). Various 2-substitutedbenzothiazoles were obtained in moderate to high yields after simple post-reaction processing including adding distilled water, filtrating, and drying. Moreover, it was found that the S-S bond of the disulfide was reduced by NaSH and also by the intermediate benzothiazoline.
- Liu, Lei,Zhang, Fa,Wang, Hongliang,Zhu, Ning,Liu, Bo,Hong, Hailong,Han, Limin
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p. 464 - 468
(2017/04/03)
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- Catalyst-Free Synthesis of 2-Arylbenzothiazoles in an Air/DMSO Oxidant System
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A straightforward strategy for the synthesis of 2-arylbenzothiazoles from 2-aminothiophenol and aryl aldehydes in air/DMSO oxidant system has been developed. This reaction is operationally simple, proceeds without catalysts, tolerates a wide range of func
- Hu, Renhe,Li, Xiaotong,Tong, Yao,Miao, Dazhuang,Pan, Qiang,Jiang, Zengqiang,Gan, Haifeng,Han, Shiqing
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supporting information
p. 1387 - 1390
(2016/05/24)
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- Epichlorohydrin cross-linked β -cyclodextrin: An environmental method for the synthesis of 2-arylbenzothiazoles derivatives in water
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In the present study, we report an environmentally benign synthesis of 2-arylbenzothiazoles derivatives from o-aminothiophenol and aldehydes in aqueous medium using β-cyclodextrin polymer as a catalyst and air as an oxidant. The polymer showed excellent c
- El-Remaily, Mahmoud Abd El Aleem Ali Ali,Soliman, Ahmed M. M.
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- Antidiabetic potential and enzyme kinetics of benzothiazole derivatives and their non-bonded interactions with α-glucosidase and α-amylase
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Benzothiazole derivatives were synthesized and their antidiabetic potential evaluated using α-glucosidase, α-amylase, non-enzymatic glycosylation of hemoglobin and advanced glycation end product inhibition assays. Compound 3l showed low IC50 va
- Puranik, Ninad V.,Puntambekar, Hemalata M.,Srivastava, Pratibha
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p. 805 - 816
(2016/03/08)
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- A method for synthesis of benzothiazole derivatives (by machine translation)
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The invention relates to a synthesis method of benzothiazole derivatives, which comprises the following step: in an organic solvent, reacting hydroxyketone compounds and 2-aminothiophenol in the presence of a catalyst and an optional accelerator to synthesize the benzothiazole derivatives. The method has the advantages of high yield, high purity, simple after-treatment and the like, provides a new route and method for synthesis of the benzothiazole derivatives, and has favorable potential applications and research value.
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Paragraph 0081-0084
(2017/02/23)
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- S8-Mediated Cyclization of 2-Aminophenols/thiophenols with Arylmethyl Chloride: Approach to Benzoxazoles and Benzothiazoles
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A metal-free approach to benzazoles from arylmethyl chlorides and 2-mercaptan/2-hydroxyanilines using elemental sulfur as a traceless oxidizing agent has been developed. The reactions proceeded in good to excellent yields, exhibiting good functional groups tolerance and gram-scale ability. A key mechanistic investigation indicated that the key intermediate trisulfide 6, which was characterized by NMR, HRMS and crystal X-ray crystallography, was separated in the reaction prior to the formation of the product.
- Gan, Haifeng,Miao, Dazhuang,Pan, Qiang,Hu, Renhe,Li, Xiaotong,Han, Shiqing
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supporting information
p. 1770 - 1774
(2016/07/07)
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- Novel Cu(0)-Fe3O4@SiO2/NH2cel as an Efficient and Sustainable Magnetic Catalyst for the Synthesis of 1,4-Disubstituted-1,2,3-triazoles and 2-Substituted-Benzothiazoles via One-Pot Strategy in Aqueous Media
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A novel, air stable, water dispersible and efficient magnetic catalyst based on copper nanoparticles onto ethylene diamine functionalized inorganic/organic composite [Cu(0)-Fe3O4@SiO2/NH2cel] has been prepared. Functionalization of inorganic/organic composite by ethylene diamine imparts desirable chemical functionality and enables the generation of active sites for the immobilization of Cu(0) nanoparticles. The novel catalyst system has been well characterized by various techniques like FTIR, TGA, XRD, SEM, HRTEM, EDX, ICP-AES, UV-Vis and VSM. Further, Cu(0)-Fe3O4@SiO2/NH2cel opens up a new avenue to introduce a very useful and efficient catalytic system for the one-pot synthesis of 1,4-disubstituted-1,2,3-triazoles via 1,3-dipolar cycloaddition of terminal acetylenes to azides, generated in situ from anilines in water at room temperature, and one-pot three component reaction of 2-iodoaniline, aldehyde and thiourea as sulphur source for the synthesis of 2-substituted-benzothiazole derivatives in water. The novel heterogeneous magnetic catalyst offers recyclability without significant deterioration in catalytic activity and can be easily recovered using an external magnet, thus making it eco-friendly and economical to perform the desired transformations.
- Bhardwaj, Madhvi,Jamwal, Babita,Paul, Satya
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p. 629 - 644
(2016/02/26)
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- Method for realizing green synthesis of 2-substituted benzothiazole derivatives
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The invention provides a method for realizing green synthesis of 2-substituted benzothiazole derivatives. The method comprises the following steps of: contacting aldehyde, o-amido aroma disulphide and metal sulfide by taking water as a solvent in the present of CO2, so as to obtain 2-substituted benzothiazole derivatives. Compared with the prior art, the method has the characteristics that o-amido aroma disulphide and multiple types of aldehyde react under the effects of water and CO2, so that the 2-substituted benzothiazole derivatives are rapidly and efficiently synthetized, and the used raw materials are easily obtained and low in cost; the synthesis method has the advantages of simplicity and convenience in operation, short steps, high yield, easiness for product purification, environmental friendliness and the like.
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Paragraph 0116; 0017; 0118; 0119; 0120; 0121; 0122; 0123
(2016/10/10)
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- An economic, simple and convenient synthesis of 2-aryl/heteroaryl/styryl/alkylbenzothiazoles using SiO2-HNO3
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The present work was undertaken to develop an economic method for the synthesis of 2-aryl/heteroaryl/styryl/alkylbenzothiazoles mediated by SiO2-HNO3. In this report, we have demonstrated the catalytic potential of SiO2-HN
- Kumar, Parvin,Bhatia, Rimpy,Kumar, Dinesh,Kamboj, Ramesh C.,Kumar, Suresh,Kamal, Raj,Kumar, Ramesh
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p. 4283 - 4292
(2015/06/30)
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- Lithium bromide catalyzed efficient and convenient synthesis of 2-arylbenzothiazole derivatives
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A new and efficient protocol was developed for synthesis of benzothiazoles using lithium bromide as catalyst under environmentally friendly conditions. The developed synthetic protocol represents a novel and very simple route for preparation of 2-substitu
- Gill, Charansingh H.,Nikam, Mukesh D.,Mahajan, Pravin S.,Chate, Asha V.,Dabhade, Sanjay K.,Badadhe, Pravin V.
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p. 7509 - 7516
(2015/02/19)
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- FeCl3/ultrasound mediated reaction of 2-aminothiophenol with aldehydes in water: Synthesis of 2-substituted benzothiazoles of pharmacological interest
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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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- Iron nanotube-silica composite (ZVI-S-PCAT modified silica composite) preparation, characterization and application as a recyclable catalytic system for 5-membered ring organic transformations
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Iron nanotube silica composite have been synthesized and studied through particle-size analysis, FTIR, SEM-EDX, TEM, XRD, UV, VSM, TGA-DTA and XPS techniques. The application of nanoframeworks as sustainable recyclable catalytic systems has been observed
- Kour, Gurpreet,Gupta, Monika,Vishwanathan,Thirunavukkarasu
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p. 14975 - 14990
(2015/08/24)
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- A simple and eco-friendly process catalyzed by montmorillonite K-10, with air as oxidant, for synthesis of 2-substituted benzothiazoles
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Simple and eco-friendly synthesis of 2-substituted benzothiazoles is described. The reaction is performed in absolute ethanol at room temperature, using a catalytic amount of montmorillonite K-10, and with continuous bubbling of air as oxidant. Simplicity
- Chen, Guo Feng,Xiao, Nan,Yang, Jing Sen,Li, Hong Yang,Chen, Bao Hua,Han, Li Fen
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p. 5159 - 5166
(2015/07/08)
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- Formation of a nanorod shaped ionogel and its high catalytic activity for one-pot synthesis of benzothiazoles
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An ionogel was synthesized through the confinement of 1,3,5-trimethyl pyrazolium chloride as an ionic liquid in a silica-gel matrix through a sol-gel process, and its catalytic activity was compared with a silica supported ionic liquid for the synthesis of benzothiazoles using 2-aminothiophenol and aldehydes/ketones. The reaction between 3-methoxyacetophenone and 2-aminothiophenol produced 2-(3-methoxyphenyl)benzothiazole, and its structure was determined using X-ray crystallography. The ionogel was characterized with SEM, TEM, FTIR and TGA.
- Sharma, Pankaj,Gupta, Monika,Kant, Rajni,Gupta, Vivek K.
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p. 5116 - 5120
(2015/07/07)
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- Unexpectedly Simple Synthesis of Benzazoles by tBuONa-Catalyzed Direct Aerobic Oxidative Cyclocondensation of o-Thio/Hydroxy/Aminoanilines with Alcohols under Air
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tBuONa-catalyzed direct aerobic oxidative cyclocondensation reactions of readily available alcohols and o-thio/hydroxy/aminoanilines under air have been developed and provide an efficient, practical, and green method for the synthesis of benzazoles. Mechanistic studies revealed that o-substituted anilines promote the initial aerobic alcohol-oxidation step, which explains the high reactivity and success of this unexpectedly simple and practical cyclocondensation method. Simple and straight: tBuONa-catalyzed direct aerobic oxidative cyclocondensation reactions of readily available alcohols and o-thio/hydroxy/aminoanilines under air provide an efficient, practical, and green method for the synthesis of benzazole heterocycles (see scheme). Mechanistic studies revealed that o-substituted anilines promote the initial aerobic alcohol-oxidation step.
- Shi, Xinkang,Guo, Junmei,Liu, Jianping,Ye, Mingde,Xu, Qing
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supporting information
p. 9988 - 9993
(2015/07/07)
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- Magnetically separable nano CeO2: A highly efficient catalyst for ligand free direct C-H arylation of heterocycles
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An efficient, ligand free, nano CeO2-Fe3O4 catalyzed direct C-H arylation of heteroarenes such as benzoxazole and benzothiazole has been carried out with aryl halides in DMSO or arenediazonium salts in water. The catalyst exhibited high activity with moderate to excellent product yields under mild reaction conditions. Nano CeO2-Fe3O4 was synthesized and characterized by SEM, TEM, EDAX, XRD, FTIR, DSC-TGA, and ICP-MS analyses. The catalytic activity and stability of the catalyst were excellent, even after the ten cycle of recyclability
- Shelkar, Radheshyam S.,Balsane, Kishor E.,Nagarkar, Jayashree M.
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supporting information
p. 693 - 699
(2015/01/30)
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- Copper-catalyzed multicomponent reactions of 2-iodoanilines, benzylamines, and elemental sulfur toward 2-arylbenzothiazoles
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A relatively cheap copper salt-catalyzed, three-component approach providing 2-arylbenzothiazoles in good to excellent yields from readily available 2-iodoanilines, benzylamines, and sulfur powder is reported. This methodology allows preparation of various classes of 2-arylbenzothiazoles and provides a general, reliable approach.
- Wang, Rui,Ding, Yong-Liang,Liu, Hong,Peng, Shu,Ren, Jie,Li, Lei
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p. 945 - 949
(2015/02/19)
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