- Functionalization of activated methylene C-H bonds with nitroarenes and sulfur for the synthesis of thioamides
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We report a method to obtain arylthioamides by the functionalization of sp3 C-H bonds in phenylacetic acids and benzyl alcohols. Reactions proceeded without the use of any solvents and were compatible with many functionalities and heterocycles. These conditions allow for a rapid synthesis of thioamides from simple, commercial substrates.
- Do, Nhan T.,Tran, Khoa M.,Phan, Hao T.,To, Tuong A.,Nguyen, Tung T.,Phan, Nam T. S.
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supporting information
p. 8987 - 8991
(2019/10/28)
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- Sulfur-Catalyzed Oxidative Coupling of Dibenzyl Disulfides with Amines: Access to Thioamides and Aza Heterocycles
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In the presence of catalytic amounts of elemental sulfur, dibenzyl disulfide/DMSO was found to be an excellent thiobenzoylating agent of amines to provide a wide range of thioamides. The reaction becomes autocatalytic when anilines substituted by an o-cyclizable group were used as nucleophile, leading to the corresponding 2-aryl aza heterocycles. (Figure presented.).
- Nguyen, Thanh Binh,Nguyen, Le Phuong Anh,Nguyen, Thi Thu Tram
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supporting information
p. 1787 - 1791
(2019/02/26)
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- Exogenous Photosensitizer-, Metal-, and Base-Free Visible-Light-Promoted C-H Thiolation via Reverse Hydrogen Atom Transfer
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Visible-light-driven, intramolecular C(sp2)-H thiolation has been achieved without addition of a photosensitizer, metal catalyst, or base. This reaction induces the cyclization of thiobenzanilides to benzothiazoles. The substrate absorbs visible light, and its excited state undergoes a reverse hydrogen-atom transfer (RHAT) with 2,2,6,6-tetramethylpiperidine N-oxyl to form a sulfur radical. The addition of the sulfur radical to the benzene ring gives an aryl radical, which then rearomatizes to benzothiazole via RHAT.
- Xu, Ze-Ming,Li, Hong-Xi,Young, David James,Zhu, Da-Liang,Li, Hai-Yan,Lang, Jian-Ping
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p. 237 - 241
(2019/01/10)
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- Decomposition of benzoylthioureas into benzamides and thiobenzamides under solvent-free conditions using iodine-alumina as the catalyst and its mechanistic study by density functional theory
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The breaking down of benzoylthioureas to benzamides and thiobenzamides in a single route using iodine-alumina as the catalyst under solvent-free conditions is highlighted. Results show that when an electron donating group, such as the methyl or methoxy group, is at the para-position of the aryl group of 1, benzamide (2) is the favoured product. When an electron withdrawing group, such as the chlorine or nitro group, is at the para-position of the aryl group of 1, thiobenzamide (3) is the favoured product. From the study of the reaction mechanism, it may be postulated that the formation of benzamide is due to the migration of the aryl group, whereas the formation of thiobenzamide may be due to the migration of the phenyl group. Thus, a new method for the formation of benzamides and thiobenzamides was developed.
- Nahakpam, Lokendrajit,Chipem, Francis A. S.,Chingakham, Brajakishor S.,Laitonjam, Warjeet S.
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supporting information
p. 2240 - 2247
(2015/03/18)
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- Organocatalytic syntheses of benzoxazoles and benzothiazoles using aryl iodide and oxone via C-H functionalization and C-O/S bond formation
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An organocatalytic protocol for the syntheses of 2-substituted benzoxazoles and benzothiazoles is described from alkyl-/arylanilides and alkyl-/arylthioanilides using 1-iodo-4-nitrobenzene as catalyst and oxone as an inexpensive and environmentally safe terminal oxidant at room temperature in air via oxidative C-H functionalization and C-O/S bond formation. The procedure is simple and general and provides an effective route for the construction of functionalized 2-alkyl-/arylbenzoxazoles and 2-alkyl-/arylbenzothiazoles with moderate to high yields. The synthetic and mechanistic aspects have been described.
- Alla, Santhosh Kumar,Sadhu, Pradeep,Punniyamurthy, Tharmalingam
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p. 7502 - 7511
(2014/09/16)
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- Palladium-catalyzed C-H cyclization in water: A milder route to 2-arylbenzothiazoles
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Water was successfully employed as a reaction medium in palladium-catalyzed C-H cyclization of thiobenzanilides. Reactions efficiently proceeded under considerably mild conditions such as 40 °C in water, providing a more practical, greener method for the synthesis of 2-arylbenzothiazoles. For some substrates, the addition of an amphiphilic surfactant greatly enhanced the process. The method represents a rare example of palladium-catalyzed C-H functionalization processes performed in water. Georg Thieme Verlag Stuttgart · New York.
- Inamoto, Kiyofumi,Nozawa, Kanako,Kondo, Yoshinori
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supporting information; experimental part
p. 1678 - 1682
(2012/07/17)
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- Conversion of thiobenzamides to benzothiazoles via intramolecular cyclization of the aryl radical cation
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A new and general method has been developed for the intramolecular cyclization of thiobenzamides to benzothiazoles via aryl radical cations as reactive intermediates. The method utilizes phenyliodine(III) bis(trifluoroacetate) (PIFA) in trifluoroethanol or cerium ammonium nitrate (CAN) in aqueous acetonitrile at room temperature to effect cyclization within 30 min in moderate yields.
- Downer-Riley, Nadale K.,Jackson, Yvette A.
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p. 7741 - 7744
(2008/12/20)
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