- 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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- Aerobic oxidative synthesis of quinazolinones and benzothiazoles in the presence of laccase/DDQ as a bioinspired cooperative catalytic system under mild conditions
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The current study applied laccase/DDQ as a bioinspired cooperative catalytic system for the synthesis of quinazolinones (80-95% yield) and benzothiazoles (65-98% yield) using air or O2 as ideal oxidants in aqueous media at ambient temperature. The aerobic oxidative cyclization reactions occur in two steps: (i) chemical cyclization; (ii) chemoenzymatic oxidation. These methods are more environment-friendly, efficient, simple and practical than other reported methods due to the use of O2 as an oxidant, laccase as an eco-friendly biocatalyst, aqueous media as the solvent and free from any toxic transition metal and halide catalysts. Therefore, these methods can be applied in pharmaceutical and other sensitive synthetic procedures.
- Abdelrasoul, Amira,Ghorashi, Nadia,Moradi, Reza,Rostami, Amin,Shokri, Zahra
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p. 14254 - 14261
(2020/04/23)
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- Synthesis of some benzothiazoles by developing a new protocol using urea nitrate as a catalyst and their antimicrobial activities
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The present communication demonstrates the development of urea nitrate as an effective and efficient catalyst for the synthesis of some 2-substituted benzothiazoles. Instant progress of reaction at room temperature under solvent-free condition, very high catalytic activity, inexpensive, clean reaction profile, operational simplicity, large-scale synthesis and appreciable yields are the main advantages of this protocol. These synthesized benzothiazoles have been evaluated for their antibacterial and antifungal activities against Gram-positive bacterium (Bacillus subtilis MTCC 121); two Gram-negative bacteria (Escherichia coli MTCC 1652 and Pseudomonas aeruginosa MTCC 741) and two fungi (Candida albicans MTCC 3017 and Saccharomyces cerevisiae MTCC 170). Compound 3n was found the most active against all the tested microbes.
- Kumar, Parvin,Bhatia, Rimpy,Khanna, Radhika,Dalal, Aarti,Kumar, Dinesh,Surain, Parveen,Kamboj, Ramesh C.
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p. 585 - 596
(2017/10/05)
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- Role of graphene oxide as a heterogeneous acid catalyst and benign oxidant for synthesis of benzimidazoles and benzothiazoles
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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)
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- Synthesis of 2-substituted benzimidazoles and benzothiazoles using Ag2CO3/Celite as an efficient solid catalyst
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An efficient and simple approach for the synthesis of 2-substituted benzimidazoles and benzothiazoles through a coupling of 1,2-phenylenediamines and 2-aminothiophenols with variety of aryl aldehydes in ethanol at 70 °C using Ag2CO3/Celite as solid catalyst is described. The procedure features short reaction time, excellent yields and simple workup.
- Soleimani, Ebrahim,Khodaei, Mohammad Mehdi,Yazdani, Hossein,Saei, Parisa,Zavar Reza, Javad
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p. 1281 - 1285
(2015/06/02)
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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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- Photo-induced intermolecular electron transfer from donating amines to accepting diarylethylenes in different solvents
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The fluorescence quenching of newly synthesized diarylethylenes by some aliphatic and aromatic amines has been carried out at room temperature in solvents of various polarities and viscosities including acetonitrile, methanol, ethanol, and cyclohexane usi
- El-Nahass, Marwa N.,Fayed, Tarek A.,El-Morsi, Mohammed A.
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p. 1757 - 1776
(2015/10/12)
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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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- Piperazinylpyrimidine modified MCM-41 for the ecofriendly synthesis of benzothiazoles by the simple cleavage of disulfide in the presence of molecular O2
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This is the first report of a sustainable and toxic metal free synthesis of benzothiazoles by the cleavage of ortho-aminothiophenol disulfide using a silica-supported heterogeneous catalyst in water in the presence of molecular O2 as a stoichiometric oxidant. For this purpose a new heterogeneous catalyst (MCM-PP) was synthesized by post synthesis grafting of 2-(piperazin-1-yl)pyrimidine functionalized organosilane onto MCM-41 mesoporous silica and it was characterized by BET surface area analysis, SAXRD, UHR TEM, CHN analysis, 13C CP MAS and 29Si MAS NMR. The reaction requires two different catalytic functions, i.e., an acidic one which is given by MCM-41 and a basic one, given by the organic base moiety anchored to the MCM-41. The greenness of the process was assured as water was exploited as the reaction medium and O2 from air as the stoichiometric oxidant. Furthermore the leaching of the active site can also be avoided as the organic moieties are covalently attached to the inorganic support. Standard leaching experiments proved that the reaction was heterogeneous with this recyclable catalyst.
- Ray, Suman,Das, Paramita,Banerjee, Biplab,Bhaumik, Asim,Mukhopadhyay, Chhanda
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p. 72745 - 72754
(2015/09/15)
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- Iron-catalyzed arylation or aroylation of benzothiazoles with benzylic alcohols and aryl ketones
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An iron-catalyzed arylation or aroylation of benzothiazoles with alcohols and aryl ketones via an in situ cross-trapping strategy has been described. Both the use of an iron catalyst and the ratio of substrates are important for this transformation, and this reaction is sensitive to the electronic effects of the substituents.
- Wang, Jian,Zhang, Xiao-Zhuan,Chen, Shan-Yong,Yu, Xiao-Qi
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p. 245 - 250
(2014/01/06)
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- Nano ceria catalyzed synthesis of substituted benzimidazole, benzothiazole, and benzoxazole in aqueous media
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A series of substituted benzimidazoles, benzothiazoles, and benzoxazoles was synthesized by combining 1,2-phenylenediamine, 2-aminothiophenol, or 2-aminophenol with aryl, heteroaryl, aliphatic, α,β-unsaturated aldehydes in the presence of nano ceria (CeO2) as an efficient heterogeneous catalyst.
- Shelkar, Radheshyam,Sarode, Sachin,Nagarkar, Jayashree
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supporting information
p. 6986 - 6990
(2013/12/04)
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- Highly efficient, mild, one pot synthesis of 2-substituted benzimidazoles, benzothiazoles and pyridoimidazoles promoted by N-iodosuccinimide
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A common and highly efficient metal-free route for the synthesis of 2-substituted benzimidazoles, benzothiazoles and pyridoimidazoles from suitable 1,2-difunctionalised aromatic compounds and various aromatic and aliphatic aldehydes and ferrocenecarboxaldehyde was developed using N-iodosuccinimide as the oxidizing agent. The methodology involved very short reaction time, mild reaction procedure and easy work-up as well as excellent yields of the products.
- Bhattacharyya, Bhaswati,Dhara, Kaliprasanna
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p. 1749 - 1759
(2014/01/17)
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- Copper-catalyzed synthesis of benzo[ b ]thiophenes and benzothiazoles using thiocarboxylic acids as a coupling partner
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An efficient copper-catalyzed approach to benzo[b]thiophene and benzothiazole derivatives using thiocarboxylic acids as a sulfur source has been developed. In the presence of CuI and 1,10-phen, and n-Pr3N as the base, (2-iodobenzyl)triphenylphosphonium bromide and (2-iodophenylimino) triphenylphosphorane reacted smoothly with thiocarboxylic acids to give benzo[b]thiophene and benzothiazole derivatives in good yields via sequential Ullmann-type C-S bond coupling and Wittig condensation.
- Yu, Hui,Zhang, Meishu,Li, Yuzhe
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p. 8898 - 8903
(2013/09/24)
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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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- Br?nsted acid catalyzed reductive amination with benzothiazoline as a highly efficient hydrogen donor
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Reductive amination of aldehyde and amine proceeded smoothly in the presence of benzothiazoline as efficient hydrogen source by means of 20 mol% trifluoroacetic acid to give the corresponding amines in excellent yields. Hydrogen-donor abilities of benzothiazoline, benzimidazoline, and benzoxazoline were compared. Georg Thieme Verlag Stuttgart - New York.
- Zhu, Chen,Akiyama, Takahiko
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supporting information; experimental part
p. 1251 - 1254
(2011/06/28)
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- Eco-friendly synthesis of 2-substituted benzothiazoles catalyzed by cetyltrimethyl ammonium bromide (CTAB) in water
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A series of 2-substituted benzothiazoles have been synthesized by the condensation of 2-aminothiophenol with aldehydes (RCHO: R = Alkyl, Aryl, Heteroaryl, 2-Arylformyl) in the presence of a catalytic amount of cetyltrimethyl ammonium bromide (CTAB) "on wa
- Yang, Xiao-Liang,Xu, Chun-Mei,Lin, Shao-Miao,Chen, Jiu-Xi,Ding, Jin-Chang,Wu, Hua-Yue,Sua, Wei-Ke
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experimental part
p. 37 - 42
(2010/08/19)
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- Application of N,N′-diiodo-N,N′-1,2-ethandiylbis(p-toluene sulfonamide) as a new reagent for synthesis of 2-arylbenzimidazoles and 2-arylbenzothiazoles under solvent-free conditions
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N,N′-Diiodo-N,N′-1,2-ethandiylbis(p-toluene sulfonamide) (NIBTS) is a good and new reagent for synthesis of 2-arylbenzimidazoles and 2-arylbenzothiazoles at room temperature under solvent-free condition with good to high yield. Absence of solvent, short reaction times, non-corrosive, operational simplicity and environmentally friendliness are the main advantages of this procedure. Copyright
- Veisi, Hojat,Ghorbani-Vaghei, Ramin,Faraji, Alireza,Ozturk, Turan
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experimental part
p. 2249 - 2254
(2011/10/08)
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- Trichloroisocyanuric acid (TCCA) as a mild and efficient catalyst for the synthesis of 2-arylbenzothiazoles
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The condensation reaction of 2-aminothiophenol with aldehydes catalyzed by 1 mol % trichloroisocyanuric acid (TCCA) was investigated. As a result, a set of diverse 2-arylbenzothiazoles were obtained in good to excellent yields at room temperature. Copyrig
- Xiao, Hui-Long,Chen, Jiu-Xi,Liu, Miao-Chang,Zhu, Dong-Jian,Ding, Jin-Chang,Wu, Hua-Yue
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supporting information; experimental part
p. 170 - 171
(2010/02/16)
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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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- The reaction of (2-alkylidenaminophenyl)sulfides with di-iso-propyl peroxydicarbonate: Radical versus non-radical pathway
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The reaction of 2-methylthio- or 2-phenylthioarylimines with di-iso-propyl peroxydicarbonate (DPDC) is described. The phenylthio-derivatives undergo cyclization to benzothiazoles via a free-radical mechanism, whereas the methylthio-analogs afford arylthiomethyl iso-propyl carbonates, together with benzothiazoles as well; this last result could be accounted for with the intervention of a non-radical mechanism operating side by side with the radical one.
- Leardini,Nanni,Santori,Zanardi
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p. 3961 - 3970
(2007/10/02)
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- GAS/SOLID-REACTIONS WITH SULFUR COMPOUNDS
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The various types of gas/solid-reactions (addition, elimination, substitution, condensation, catalyzed cycloaddition) in different branches of sulfur chemistry (heterocycles, S-vinyl-compounds, thioethers, thiols, sulfur dioxide) are reviewed, new types a
- Kaupp, Gerd,Luebben, Doris,Sauerland, Olaf
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p. 109 - 120
(2007/10/02)
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- Application of Phase-Transfer Catalysis to the Synthesis of Mono- and Bis-stilbenes and Styryls
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A novel and convenient method has been developed for the synthesis of substituted stilbenes by the condensation of active methyl group in suitably substituted toluenes with aromatic aldehydes in aq. medium at room temperature using benzyltriethylammonium chloride as a phase-transfer catalyst.This method has also been applied for the preparation of heterocyclic styryls and extended to the synthesis of bis-stilbenes and bis-styryls using aromatic dialdehydes in place of monoaldehydes.A comparison of the results shows that the present method is superior to the conventional methods in many respects.
- Lokhande, S. B.,Rangnekar, D. W.
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p. 485 - 488
(2007/10/02)
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