- Metal-Free Synthesis of Imidazo[2,1-b]thiazoles from Thioimidazoles and Ketones Mediated by Selectfluor
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This paper presents a practical and efficient strategy for the preparation of imidazol[2,1-b]-thiazoles from thioimidazoles and ketones mediated by Selectfluor. The proposed mechanism suggests that this transformation took place through electrophilic thiolation at an α-carbon of ketones by sulfur cation, which is produced by the oxidation of thioimidazole by Selectfluor. This metal-free protocol tolerated various ketones, including methyl ketones or non-methyl ketones, aryl ketones or aliphatic ketones. The experimental results indicated that steric hindrance of the substituents at the α-position of ketones or on the aromatic ring of aryl ketones had significant influence on the yields of imidazol[2,1-b]-thiazoles. Thioimidazole and benzothioimidazoles were well tolerated while 5-substituted benzothioimidazoles provided the mixture of the corresponding 6-substituted and 7-substituted benzoimidazo[2,1-b]thiazole products.
- Zhao, Jinwu,Xiao, Qiannan,Chen, Jiaxi,Xu, Jingxiu
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- Salicylic Acid-Promoted Three-Component Annulation of Benzimidazoles, Aryl Nitroalkenes and Elemental Sulfur
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Herein, a three-component cyclization reaction of benzimidazoles, aryl nitroalkenes and elemental sulfur has been developed. Cheap and easily available salicylic acid found to be an efficient mediator for the present transformation. This protocol provides
- Mei, Ruhuai,Xiong, Feng,Yang, Chenrui,Zhao, Jinwu
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supporting information
p. 1861 - 1866
(2021/02/12)
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- Polysubstituted benzimidazothiazole, derivative and synthesis method of polysubstituted benzimidazothiazole
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The invention relates to polysubstituted benzimidazothiazole, a derivative and a synthesis method of the polysubstituted benzimidazothiazole. According to the method, in the air atmosphere for the first time, a benzimidazole compound, a beta-nitrostyrolene compound and sulfur powder are promoted to be converted into benzo [4, 5] imidazo [2, 1-b] thiazole and a derivative by an acid, and the prepared benzo [4, 5] imidazo [2, 1-b] thiazole is stable in molecular structure and excellent in chemical property. Reaction raw materials of the synthesis method are cheap and easy to obtain, pretreatmentis not needed, and the atom economy of the reaction is high; only cheap aromatic acid needs to be used in the reaction, environmental pollution is reduced, raw materials are saved, and reaction costis reduced; the whole reaction system is simple, reaction conditions are mild, reaction equipment is less, experimental operation is simple and convenient, and material sources are wide.
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Paragraph 0058-0064
(2020/05/30)
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- Copper-catalyzed aminothiolation of terminal alkynes with tunable regioselectivity
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A simple, mild, and efficient catalytic aminothiolation of terminal alkynes for the synthesis of both 2- and 3-substituted thiazolo[3,2-a]benzimidazoles is established upon catalysis with copper(i), in which complementary regioselectivities could be achieved by using sterically different phenanthroline-based ligands.
- Kuang, Jinqiang,Xia, Yuanzhi,Yang, An,Zhang, Heng,Su, Chenliang,Lee, Daesung
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supporting information
p. 1813 - 1816
(2019/02/12)
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- A benzo imidazo [2, 1 - b] thiazole derivatives
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The invention discloses a preparation method of a benzimidazo[2,1-b]thiazole derivative. According to the method, the benzimidazo[2,1-b]thiazole derivative is synthesized by one step of performing reaction on a 2-thioimidazole compound serving as a raw ma
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- Synthesis of Benzo[4,5]imidazo[2,1-b]thiazole by Copper(II)-Catalyzed Thioamination of Nitroalkene with 1H-Benzo[d]imidazole-2-thiol
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A Copper(II)-catalyzed thioamination of β-nitroalkene with 1H-benzo[d]imidazole-2-thiol has been developed for the synthesis of benzo[4,5]imidazo[2,1-b]thiazole derivatives. A variety of N-fused benzoimidazothiazole derivatives are obtained in high yields through successive C?N and C?S bond formations. This protocol is also applicable to β-substituted β-nitroalkenes to afford 2,3-disubstituted benzoimidazothiazoles. (Figure presented.).
- Jana, Sourav,Chakraborty, Amrita,Shirinian, Valerii Z.,Hajra, Alakananda
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p. 2402 - 2408
(2018/05/08)
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- Copper- and Palladium-Catalyzed Cross-Coupling Reactions for the Synthesis of N-Fused Benzo[4,5]imidazo[2,1-b]thiazole Derivatives via Substituted trans-1,2-Diiodoalkenes, 1H-Benzo[d]imidazole-2-thiols, and Halobenzenes
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Two transition metal (Cu and Pd)-catalyzed C-S, C-N, and C-C bond cross-coupling reactions for the preparation of N-fused benzo[4,5]imidazo[2,1-b]thiazole derivatives were developed. A variety of 3-substituted and 2,3-disubstituted benzo[4,5]imidazo[2,1-b]thiazoles were efficiently and conveniently synthesized from the coupling reaction via trans-1,2-diiodoalkenes, 1H-benzo[d]imidazole-2-thiols, and halobenzenes in moderate to excellent yields.
- Shen, Guodong,Yang, Bingchuan,Huang, Xianqiang,Hou, Yaxin,Gao, Huan,Cui, Jichun,Cui, Chuansheng,Zhang, Tongxin
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p. 3798 - 3805
(2017/04/11)
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- Access to N-thioalkenyl and N-(o-thio)aryl-benzimidazol-2-ones by ring opening of thiazolobenzimidazolium and benzimidazobenzothiazolium salts and C-O bond cleavage of an alkoxide
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We report herein the synthesis of highly functionalized 1,3-dihydro-2H-benzimidazol-2-ones via a ring opening of thiazolo[3,2-a]benzimidazolium or benzimidazo[2,1-b][1,3]benzothiazol-6-ium salts and an unusual C-O bond cleavage of an alkoxide. A large variety of benzimidazolones bearing an original N-thioalkenyl or N-(o-thio)aryl group was obtained in high yields. The developed chemistry provides efficient and rapid access to the privileged benzimidazol-2-one scaffold.
- Andreoli, Federico,Kaid-Slimane, Radia,Coppola, Fabien,Farran, Daniel,Roussel, Christian,Vanthuyne, Nicolas
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p. 3233 - 3241
(2015/03/30)
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- Copper-catalyzed synthesis of N-fused heterocycles through regioselective 1,2-aminothiolation of 1,1-dibromoalkenes
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The first aminothiolation of 1,1-dibromoalkene is described using an inexpensive copper/N,N-dimethylethylenediamine catalyst. The method provides a powerful means of using easily available 1,1-dihaloalkenes as precursors to fused heterocycles.
- Xu, Hui,Zhang, Yin,Huang, Jianqiang,Chen, Wanzhi
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supporting information; experimental part
p. 3704 - 3707
(2010/10/20)
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- Hypervalent Iodine in the Synthesis of Bridgehead Heterocycles: Novel and Facile Syntheses of 3-Substituted-5,6-Dihydroimidazothiazoles and 3-Phenylthiazolobenzimidazole from Acetophenones using benzene
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The synthesis of 3-substituted-5,6-dihydroimidazothiazoles 3a-f has been achieved by using a novel and facile method involving hypervalent iodine oxidation of acetophenones 1a-f with benzene, followed by the treatment of the
- Prakash, Om,Rani, Neena,Goyal, Seema
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p. 707 - 710
(2007/10/02)
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- SYNTHESIS OF THIAZINO !4,3-ALPHA! AND THIAZOLO !3,2- ALPHA! BENZIMIDAZOLES USING POLYPHOSPHORIC ACID AS A CONDENSING AGENT
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Synthesis of 3-arylthiazolo !4,3- alpha! benzimidazoles and 4- aryl-1H- (1,4) thiazino !4,3- alpha! benzimidazoles through cyclodehydration of venzimidazothioacetophenones and 2- benzimidazolyl-methyl- thioacetophenones with polyphosphoric acid are report
- SINGH S,SINGH H,SINGH M,NARANG KS
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p. 230 - 232
(2007/10/04)
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