- Selective C-H chalcogenation of thiazoles: Via thiazol-2-yl-phosphonium salts
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Thiazoles and benzothiazoles undergo regioselective C2-H chalcogenation via the sequence of thiazole C2-functionalization with phosphines to produce phosphonium salts which in turn react with S- and Se-centered nucleophiles to give products of C2-H chalco
- Zi, You,Wagner, Konrad,Sch?mberg, Fritz,Vilotijevic, Ivan
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- One-Pot Substitution of Aliphatic Alcohols Mediated by Sulfuryl Fluoride
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The Mitsunobu reaction is a powerful transformation for the one-pot activation and substitution of aliphatic alcohols. Significant efforts have focused on modifying the classic conditions to overcome problems associated with purification from phosphine-based byproducts. Herein, we report a phosphine free method for alcohol activation and substitution that is mediated by sulfuryl fluoride. This new method is effective for a wide range of primary alcohols using phthalimide, di-tert-butyl-iminodicarboxylate, and aromatic thiol nucleophiles in 74 % average yield. Activated carbon nucleophiles and a deactivated phenol were also effective for this reaction in good yields. Secondary alcohols were also successful substrates using aryl thiols, affording the corresponding sulfides in 56 % average yield with enantiomeric ratios up to 99:1. This new protocol has a distinct synthetic advantage over many existing phosphine-based methods as the byproducts are readily separable. This feature was exploited in several examples that did not require chromatography for purification. Furthermore, the mild reaction conditions enabled further in situ derivatization for the one-pot conversion of alcohols to amines or sulfones. This method also provides a boarder nucleophile scope compared to existing phosphine-free methods.
- Dubois, Rudy,Epifanov, Maxim,Hodgson, Jack W.,Mo, Jia Yi,Sammis, Glenn M.
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supporting information
p. 4958 - 4962
(2020/04/22)
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- Efficient Thiolation of Alcohols Catalyzed by Long Chained Acid-Functionalized Ionic Liquids under Mild Conditions
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Thioethers as important building blocks have been usually found in organic synthesis. Herein, a series of long chained acid-functionalized ionic liquids derived from pyrrolidine were applied for the thiolation of alcohols to synthesize different compounds containing thioether structures. This kind of ionic liquids exhibited higher efficiency than general ionic liquids based on imidazole, providing up to 99 % yield with [BsCtP][OTf] as the catalyst at room temperature for 0.25 h. The results indicated that the activities of the ionic liquids have relationship with the side chain length of ionic liquids based on pyrrolidine, anions and cations. The catalytic system had wide substrate scope and was applicable for the reaction of aromatic primary and secondary alcohols and thiols including aliphatic and aromatic thiols, benzothiazole-2-thiols and benzooxazole-2-thiols. Besides, there was no obvious change in activity of the catalyst after six runs. Thus, the catalytic system exhibited good recyclability. Additionally, carbocations should be the key intermediate and several functionalized groups of the ionic liquids have synergetic effect for the thiolation.
- Miao, Chengxia,Zhuang, Hongfeng,Wen, Yating,Han, Feng,Yang, Qing-Feng,Yang, Lei,Li, Zhen,Xia, Chungu
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p. 3012 - 3021
(2019/05/16)
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- Facile synthesis of a series of non-symmetric thioethers including a benzothiazole moiety and their use as effcient in vitro anti-trypanosoma cruzi agents
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A series of 2-benzylsulfanyl benzothiazole (BTA) derivatives were synthesized and fully characterized and in vitro tested against two strains of T. cruzi (NINOA and INC-5), exhibiting good activities at low concentrations.
- Avila-Sorrosa, Alcives,Tapia-Alvarado, Jazz D.,Nogueda-Torres, Benjamín,Chacón-Vargas, Karla Fabiola,Díaz-Cedillo, Francisco,Vargas-Díaz, María Elena,Morales-Morales, David
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- A Practical Access to Functionalized Alkyl Sulfinates
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We describe herein a three-step synthesis of aliphatic sulfinates. This cost-effective method involves the use of 2-mercaptobenzothiazole under mild conditions and exhibits good yields (up to 78% over three steps). This approach provides an access to a wi
- Tran,Flamme,Chagnes,Haddad,Phansavath,Ratovelomanana-Vidal
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supporting information
p. 1622 - 1626
(2018/06/12)
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- Synthesis and application of a novel asymmetric azo reagent: 1-(tert-butyl)-2-(4-chlorobenzyl) azodicarboxylate (tBCAD)
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A series of novel asymmetric azo reagents, 1-(tert-butyl)-2-(4-substituted benzyl) azodicarboxylate, were prepared. The synthetic process has the advantage of simpleness, easy operation, mild reaction condition and high yield. The 1-(tert-butyl)-2-(4-chlorobenzyl) azodicarboxylate (tBCAD) was selected for its stability and convenience to handle, and its precursor can be recycled by recrystallization with toluene. The tBCAD and DIAD were applied to a wide variety of Mitsunobu reactions. The experimental results showed that the performance of tBCAD in Mitsunobu reaction was comparable to that of DIAD, while the stability of tBCAD was much better than DIAD. Thus, tBCAD can be a novel, stable, effective azo-reagent for the Mitsunobu reaction.
- Xie, Jian,Xu, Cai,Dai, Qianjin,Wang, Xiaozhong,Xu, Gang,Chen, Yingqi,Dai, Liyan
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p. 5321 - 5326
(2017/08/04)
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- Direct Synthesis of Thioethers from Carboxylates and Thiols Catalyzed by FeCl3
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A new and efficient method has been developed for the synthesis of thioethers from carboxylates and thiols. The reaction proceeds via a Fe(III)-catalyzed direct displacement of carboxylates from benzylic or allylic esters by heterocyclic thiols. Short rea
- Venkatesham, Kunuru,Bhujanga Rao, Chitturi,Dokuburra, Chanti Babu,Bunce, Richard A.,Venkateswarlu, Yenamandra
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p. 11611 - 11617
(2015/12/01)
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- A comparative study of Cu(II)-assisted vs Cu(II)-free chalcogenation on benzyl and 2°/3°-cycloalkyl moieties
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A relative synthetic strategy toward intermolecular oxidative C -Chalcogen bond formation of alkanes has been illustrated using both Cu(II) assisted vs Cu(II) free conditions. This led to construction of a comparative study of hydrocarbon benzylic and 2°/ 3°-cycloalkyl moieties bond sulfenylation and selenation protocol by the chalcogen sources, particularly sulfur and selenium, respectively. In addition, this protocol disclosed the auspicious formation of sp3 C-S coupling products over leading the sp3 C-N coupling products by using 2-mercaptobenzothiazole (MBT) substrates.
- Sahoo, Santosh K
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p. 2151 - 2157
(2016/01/12)
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- Acidic-functionalized ionic liquid as an efficient, green, and metal-free catalyst for benzylation of sulfur, nitrogen, and carbon nucleophiles to benzylic alcohols
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A series of HSO4- functionalized ILs was synthesized and used as efficient, green, and metal-free catalysts for benzylation. Notably, the catalytic system has wide substrate scopes and the ionic liquid catalysts were applied to investigate three different types of nucleophiles to give the desired benzylation products with moderate to excellent yields.
- Chu, Xue-Qiang,Jiang, Ran,Fang, Yi,Gu, Zheng-Yang,Meng, Hua,Wang, Shun-Yi,Ji, Shun-Jun
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supporting information
p. 1166 - 1174
(2013/02/25)
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- Structure-activity relationships of 2-benzylsulfanylbenzothiazoles: Synthesis and selective antimycobacterial properties
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A set of 2-benzylsulfanyl derivatives of benzothiazole was synthesized and evaluated for antimicrobial and cytotoxic activities. The biological screening on antimicrobial activity against a panel of Gram-positive and Gramnegative bacteria, yeasts and fung
- Klimesova, Vera,Koi, Jan,Palat, Karel,Stolarikova, Jirina,Dahse, Hans-Martin,Moellmann, Ute
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experimental part
p. 281 - 292
(2012/09/08)
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- Ga(OTf)3-catalyzed direct substitution of alcohols with sulfur nucleophiles
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It is reported that Ga(OTf)3 catalyzes the direct displacement of alcohols with sulfur nucleophiles. The products are versatile intermediates that can be utilized in carbon - carbon, carbon - sulfur bond formation or used in modified Julia olef
- Han, Xinping,Wu, Jimmy
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supporting information; experimental part
p. 5780 - 5782
(2011/03/18)
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- Total synthesis of (-)-blepharocalyxin D
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The Prins cyclization strategy was successfully applied in the total synthesis of (-)-blepharocalyxin D, a cytotoxic dimeric diarylheptanoid isolated from Alpinia blepharocalyx.
- Ko, Haye Min,Lee, Dong Gil,Kim, Min Ah,Kim, Hak Joong,Park, Jaejoon,Lah, Myoung Soo,Lee, Eun
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p. 141 - 144
(2007/10/03)
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- Stereoselective synthesis of (-)-blepharocalyxin D
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The Prins cyclization strategy was successfully applied in the stereoselective synthesis of (-)-blepharocalyxin D (1), a cytotoxic dimeric diarylheptanoid isolated from Alpinia blepharocalyx.
- Ko, Haye Min,Lee, Dong Gil,Kim, Min Ah,Kim, Hak Joong,Park, Jaejoon,Lah, Myoung Soo,Lee, Eun
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p. 5797 - 5805
(2008/02/03)
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- Stereochemistry of direct olefin formation from carbonyl compounds and lithiated heterocyclic sulfones
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The conditions for the title reaction were studied for the 2-benzothiazole and 2-pyridine series and for some examples in the 2-pyrimidine series.The olefin preparations were generally observed to be more efficient for 2-BT-sulfone systems.From the data of the hundred cases studied, it can be concluded that (E)-olefins are obtained: (i) from saturated BT-sulfones and aromatic aldehydes; and (ii) from benzylic BT-sulfones and branched saturated aldehydes (isobutyraldehyde, pivalaldehyde) or α,β-ethylenic or aromatic aldehydes. (Z)-olefins arise: (i) fom propargylic BT-sulfones and saturated or aromatic aldehydes; and (ii) from allylic or benzylic Pyr-sulfones and saturated aldehydes.Possible mechanisms for this new olefination procedure were examined. - heteroaromatic sulfones, organolithium derivatives, intramolecular ipso reactions, stereochemistry, elimination, olefination.
- Baudin, J. B.,Hareau, G.,Julia, S. A.,Lorne, R.,Ruel, O.
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p. 856 - 878
(2007/10/02)
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