22901-00-4Relevant academic research and scientific papers
Room temperature HFIP/Ag-promoted palladium-catalyzed C–H functionalization of benzothiazole with iodoarenes
Bhujbal, Yuvraj,Gharpure, Santosh J.,Kapdi, Anant R.,Kommyreddy, Saidurga Prasad,Kori, Santosh,Vadagaonkar, Kamlesh
supporting information, p. 847 - 850 (2022/02/01)
A versatile synthetic protocol involving the room temperature direct arylation of benzothiazole with a wide variety of iodoarenes under Ag-promoted Pd-catalyzed conditions in HFIP as the reaction solvent has been presented. A sequential HFIP-promoted sele
KOtBu-Promoted Halogen-Bond-Assisted Intramolecular C-S Cross-Coupling of o-Iodothioanilides for the Synthesis of 2-Substituted Benzothiazoles
Nandy, Anuradha,Sekar, Govindasamy
, p. 15825 - 15834 (2021/11/01)
An efficacious and mild KOtBu-promoted intramolecular C-S cross-coupling of ortho-iodothioanilides in conjunction with a catalytic quantity of phenanthroline as an additive has been described for the convenient synthesis of 2-substituted benzothiazoles. The methodology is suitable for attaining a wide variety of 2-alkyl- and 2-aryl-substituted benzothiazoles. Single-crystal XRD, DFT calculations, NMR, and UV studies suggest that halogen bonds between the units of ortho-iodothioanilides may assist in the electron transfer process.
Improved, gram-scale synthesis of sildenafil in water using arylacetic acid as the acyl source in the pyrazolo[4,3-d]pyrimidin-7-one ring formation
Laha, Joydev K.,Gulati, Upma,Saima,Gupta, Anjali,Indurthi, Harish Kumar
supporting information, p. 2643 - 2648 (2021/02/16)
An improved, gram-scale synthesis of the blockbuster drug sildenafil, used for the treatment of male erectile dysfunction, has been developed. Unlike the previous literature, the current method demonstrates the use of arylacetic acid as an acyl source, a cheap oxidant K2S2O8, and water as the reaction medium in the key step of pyrrazolo[4,3-d]pyrimidin-7-one ring formation. As well as being a green and benign approach, the current method reduces the cost by half compared to our previous strategy. In addition, the general relevance of the method has been demonstrated in the synthesis of a variety of quinazolinone and benzothiazole derivatives with excellent functional group tolerance.
α-Keto Acids as Triggers and Partners for the Synthesis of Quinazolinones, Quinoxalinones, Benzooxazinones, and Benzothiazoles in Water
Huang, Jian,Chen, Wei,Liang, Jiazhi,Yang, Qin,Fan, Yan,Chen, Mu-Wang,Peng, Yiyuan
, p. 14866 - 14882 (2021/10/25)
A general and efficient method for the synthesis of quinazolinones, quinoxalinones, benzooxazinones, and benzothiazoles from the reactions of α-keto acids with 2-aminobenzamides, benzene-1,2-diamines, 2-aminophenols, and 2-aminobenzenethiols, respectively, is described. The reactions were conducted under catalyst-free conditions, using water as the sole solvent with no additive required, and successfully applied to the synthesis of sildenafil. More importantly, these reactions can be conducted on a mass scale, and the products can be easily purified through filtration and washing with ethanol (or crystallized).
ZnO-NPs catalyzed condensation of 2-aminothiophenol and aryl/alkyl nitriles: Efficient green synthesis of 2-substituted benzothiazoles
Dhawale, Kiran D.,Ingale, Ajit P.,Shinde, Sandeep V.,Thorat, Nitin M.,Patil, Limbraj R.
, p. 1588 - 1601 (2021/03/18)
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.
Synthesis of benzothiazoles using fluorescein as an efficient photocatalyst under visible light
Chen, Haodong,Lei, Mayan,Liu, Chunyan,Sun, Wuji,Wang, Kaixuan,Wang, Xueyao,Zhong, Qidi
, (2021/06/22)
This work reports a novel and efficient method for the synthesis of benzothiazoles using 2-aminothiophenol derivatives in conjunction with aromatic aldehyde as starting materials via visible-light-induced condensation cyclization. Utilizing fluorescein as the photocatalyst and blue LED lamp as the light source, the reaction proceeds in the presence of a molecular oxygen atmosphere without the need for metal catalyst or an additional oxidant. Significantly, this method exhibits good tolerance in substrates, and a variety of 2-aminothiophenol derivatives and aromatic aldehyde are amenable to producing the corresponding benzothiazoles in high to excellent yields.
Ultrasound-assisted efficient and green synthesis of 2-substituted benzothiazoles under solvent-free condition using recyclable sulfated tungstate
Pise, Ashok S.,Ingale, Ajit P.,Dalvi, Navnath R.
supporting information, p. 3629 - 3641 (2021/10/12)
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.
Fast and high-efficiency synthesis of 2-substituted benzothiazoles via combining enzyme catalysis and photoredox catalysis in one-pot
Yang, Zeng-Jie,Gong, Qing-Tian,Yu, Yuan,Lu, Wei-Fan,Wu, Zhe-Ning,Wang, Na,Yu, Xiao-Qi
supporting information, (2021/01/14)
An efficient and green method, combining enzymatic and visible-light catalysis for synthesis of the widely applicable 2-substituted benzothiazoles, has been developed. This method features a relay catalysis protocol consisting of biocatalytic promiscuity
Preparation method of 2-aryl benzothiazole compound
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Paragraph 0116-0118, (2020/05/09)
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.
NCS/TBHP promoted C2 arylation of benzothiazoles with aldehydes in DMSO
Xu, Wen-Xiu,Ye, Fei-Xia,Liu, Xing-Hai,Weng, Jian-Quan
, (2020/03/19)
A N-chlorosuccinimide catalyzed oxidative synthesis of 2-aryl benzothiazole from benzothiazoles and aryl aldehydes using tert-butyl peroxybenzoate as an oxidant in dimethyl sulfoxide (DMSO) has been developed in moderate to good yields. Solvent DMSO as a strong Lewis base plays an efficient role in the reaction. Various substrates were tolerated under optimized conditions affording the arylated products in 12–94% yields for 28 examples. Additionally, acylated benzothiazoles were produced with 4 examples.
