- Mechanism of the CuII-catalyzed benzylic oxygenation of (aryl)(heteroaryl)methanes with oxygen
-
A mechanistic study of the copper-catalyzed oxidation of the methylene group of aryl(di)azinylmethanes was performed. Initial reaction rates were measured making use of in situ IR reaction monitoring and a kinetic analysis of the reaction was executed. The reaction proved to be first order in oxygen concentration. For substrate and acid concentration, saturation kinetics due to O2 mass transfer limitation were observed. The occurrence of mass transfer limitation was further confirmed by examining the effect of the stirring rate on the initial reaction rate. Interestingly, the effect of the concentration of the catalyst on the rate shows that higher loadings result in a maximal initial rate, followed initially by a steady decrease and subsequently a rate plateau when the concentration is increased further. Mass transfer limitation and increased concentration of dinuclear catalytically active species rationalizes this hitherto unprecedented rate behavior. Continuous-wave and pulsed electron paramagnetic resonance methods were used to characterize the catalytic species present in the solution during the reaction and confirmed the presence of both mono- and dinuclear copper species. Analysis of a diverse substrate scope points towards imine-enamine tautomerization as a crucial process in the oxidation reaction. DFT calculations of these equilibrium constants (pKeq) provided us with a qualitative tool to predict whether or not a substrate is viable for oxidation under the reaction conditions developed.
- Sterckx, Hans,De Houwer, Johan,Mensch, Carl,Caretti, Ignacio,Tehrani, Kourosch Abbaspour,Herrebout, Wouter A.,Van Doorslaer, Sabine,Maes, Bert U. W.
-
-
Read Online
- Silver-Assisted Oxidative Isocyanide Insertion of Ethers: A Direct Approach to β-Carbonyl α-Iminonitriles
-
An efficient silver-assisted oxidative coupling of simple ethers with tert-butyl isocyanide was realized in the presence of DDQ. The direct synthesis of high density functional β-carbonyl α-iminonitriles was achieved in a single step with high yields through the synergetic cascade isocyanide insertion into C(sp3)-H bond, where the isocyanide was used as crucial "CN" and "C=N" sources and the tert-butoxyl group acted as the carbonyl source. Diverse reactivity of β-carbonyl α-iminonitriles has been demonstrated.
- Zhao, Leiyang,Liu, Bingxin,Tan, Qitao,Ding, Chang-Hua,Xu, Bin
-
-
Read Online
- S 8-Mediated Cyclization of Bis(2-aminophenyl) Disulfide/Diselenide with Arylacetylenes/Styrenes: Access to 2-(Arylmethyl)-1,3-benzothiazoles/benzoselenazoles
-
A novel S8-mediated approach to benzothiazoles/benzoselenazoles from bis(2-aminophenyl) disulfides/diselenides and phenylacetylenes or styrenes has been developed. 2-(Arylmethyl)-1,3-benzoselenazoles were comprehensively synthesized for the first time. The reactions proceeded in moderate to excellent yields, and with a gramscale application.
- Gan, Haifeng,Feng, Caojian,Zhao, Lihuan,Cao, Mengru,Wu, Hongli
-
-
- A Novel PIFA/KOH Promoted Approach to Synthesize C2-arylacylated Benzothiazoles as Potential Drug Scaffolds
-
To discover an efficient and convenient method to synthesize C2-arylacylated benzothiazoles as potential drug scaffolds, a novel [bis(trifluoroacetoxy)iodo]benzene(PIFA)/KOH synergistically promoted direct ring-opening C2-arylacylation reaction of 2H-benz
- Hu, Zhi-Gang,Huang, Zhen,Sun, Xiao-Tong,Weng, Jian-Quan,Zhou, Ling-Li
-
-
- One-pot synthesis of 2-acylbenzothiazoles from 2-aminobenzenethiols and arylacetonitriles via cyclization and sequential oxidation
-
An efficient one-pot method to access 2-acylbenzothiazoles via AlCl3-mediated cyclization reaction and I2-promoted sequential oxidation reaction of 2-aminobenzenethiols with arylacetonitriles was developed. This reaction proceeds smoothly with a wide range of arylacetonitriles containing different functional groups to give the corresponding products in moderate to good yields under mild conditions. Moreover, this reaction was conveniently conducted on a gram scale, and the yield is still up to 68%.
- Zhang, Shanshan,Wang, Shiwei,Leng, Yuting,Wu, Yangjie
-
-
- Microwave-assisted controllable synthesis of 2-acylbenzothiazoles and bibenzo[b][1,4]thiazines from aryl methyl ketones and disulfanediyldianilines
-
A condition-controlled strategy for selectively synthesis of 2-acylbenzothiazoles and bibenzo[b][1,4]thiazines from aryl methyl ketones and disulfanediyldianilines was realized using I2/DMSO or I2/MeCN systems, respectively. The desired products were synthesized in only 15 min with moderate to excellent yields (50%-90%) under microwave-assisted, metal-free conditions. The strategy provides a great advantage for selective synthetic applications in the efficient synthesis of benzothiazoles and bibenzothiazines heterocycle compounds.
- Qi, Yuquan,Gu, Xiaoyu,Huang, Xianqiang,Shen, Guodong,Yang, Bingchuan,He, Qingpeng,Xue, Zechun,Du, Mengcheng,Shi, Lilong,Yu, Bing
-
supporting information
p. 3544 - 3547
(2021/07/02)
-
- Visible-light-promoted photocatalyst-free alkylation and acylation of benzothiazoles
-
Herein we report a protocol for the visible-light-mediated alkylation/acylation reaction of benzothiazoles. Alkyl/acyl substituted Hantzsch esters are easily prepared and rationally used as radical precursors. In the presence of BF3·Et2O and Na2S2O8, various benzothiazole derivatives were readily obtained in good yields. Our user-friendly protocol can proceed by simple irradiation with blue LEDs (λ = 465 nm) and without the assistance of external photocatalysts. The reaction is also characterized by mild conditions and scalability, thus offering an alternative and efficient tool for the synthesis of 2-functionalized benzothiazoles.
- Jiang, Pengxing,Liu, Li,Tan, Jiajing,Du, Hongguang
-
supporting information
p. 4487 - 4491
(2021/05/31)
-
- Oxidant/Solvent-Controlled I2-Catalyzed Domino Annulation for Selective Synthesis of 2-Aroylbenzothiazoles and 2-Arylbenzothiazoles under Metal-Free Conditions
-
A simple and practical domino protocol for the selective synthesis of 2-aroylbenzothiazoles and 2-aryl benzothiazoles catalyzed by I2 is developed under metal-free conditions. The reaction outcomes are exclusively controlled by the reaction oxidant/medium. With DMSO employed as both the solvent and the oxidant, an oxidation of aromatic methyl ketones takes precedence over the condensation with 2-aminobenzenethiols. On the other hand, when the reaction was carried out in PhNO2 or in 1,4-dioxane containing PhNO2, the condensation of aromatic methyl ketones with 2-aminobenzenethiols has priority to form imines which is followed by an oxidation of the methyl group from ketones to afford 2-arylbenzothiazoles as a sole product. The PhNO2/I2 co-catalytic system is proposed first time.
- Ma, Renchao,Ding, Yuxin,Chen, Rener,Wang, Zhiming,Wang, Lei,Ma, Yongmin
-
p. 310 - 321
(2021/01/09)
-
- C2 substituted 2H-benzothiazole aryl acylated derivative, and synthesis method and application thereof
-
The invention discloses a C2 substituted 2H-benzothiazole aryl acylated derivative, and a synthesis method and application thereof. The preparation method of the derivative comprises the following steps: mixing substituted 2H-benzothiazole and substituted methyl benzene, adding into a solvent, in the presence of an oxidizing agent Selectfluor and an additive trifluoroacetic acid, carrying out a heating and stirring reaction in the air atmosphere, performing TLC monitoring is conducted till the reaction is finished, and separating and purifying the obtained reaction liquid to obtain the target product C2 substituted 2H-benzothiazole aryl acylated derivative. The substituted methyl benzene used in the invention is low in price, easy to obtain and good in chemical stability, the method has the advantages of being high in atom economy, simple in catalytic system, free of transition metal catalysts, good in product yield, wide in substrate range and the like, and the prepared compound structure can be further optimized as an anti-tumor drug lead.
- -
-
Paragraph 0020-0022
(2021/07/08)
-
- C2-arylacylation of 2H-benzothiazoles with methyl arenes via Selectfluor oxidation
-
An efficient Selectfluor-oxidative protocol was developed for the direct C2-arylacylation of 2H-benzothiazoles via the radical reaction of 2H-benzothiazoles with methyl arenes. Selectfluor can effectively promote the oxidative cross-coupling without an ex
- Chen, Bo,Kong, Yao-Lei,Liu, Jin-Chuan,Lu, Qi,Sun, Xiao-Tong,Weng, Jian-Quan
-
supporting information
(2021/06/03)
-
- Electrochemical Oxidative Functionalization of Arylalkynes: Access to α,α-Dibromo Aryl Ketones
-
A general and effective protocol to synthesize α,α-dibromo aryl ketones has been developed via an electrochemical oxidative method. The reaction proceeds smoothly at room temperature in an undivided cell without the addition of external oxidants. In the reaction process, LiBr acts as both bromine source and supporting electrolyte. This electrooxidation strategy has good substrate applicability and functional group compatibility. Moreover, the reaction could be scaled up efficiently in a continuous flow cell. The target product could undergo further functionalization for the synthesis of some useful heterocyclic compounds. (Figure presented.).
- Wang, Dan,Wan, Zhaohua,Zhang, Heng,Lei, Aiwen
-
supporting information
p. 1022 - 1027
(2020/12/31)
-
- K2S2O8activation by glucose at room temperature for the synthesis and functionalization of heterocycles in water
-
While persulfate activation at room temperature using glucose has primarily been focused on kinetic studies of the sulfate radical anion, the utilization of this protocol in organic synthesis is rarely demonstrated. We reinvestigated selected K2S2O8-mediated known organic reactions that invariably require higher temperatures and an organic solvent. A diverse, mild functionalization and synthesis of heterocycles using the inexpensive oxidant K2S2O8 in water at room temperature is reported, demonstrating the sustainability and broad scope of the method. Unlike traditional methods used for persulfate activation, the current method uses naturally abundant glucose as a K2S2O8 activator, avoiding the use of higher temperature, UV light, transition metals or bases.
- Hunjan, Mandeep Kaur,Laha, Joydev K.
-
p. 8437 - 8440
(2021/09/02)
-
- Photo-redox catalyzed dehydrazinative acylation of N-heterocycles: Via Minisci reaction
-
Visible light-induced acylation of heteroaromatic compounds have been achieved using benzoyl hydrazides as an efficient acyl source under mild reaction conditions. The photo-redox catalyzed oxidative cleavage of hydrazides leads to in situ formation of ac
- Hafeez, Saira,Saeed, Aamer
-
p. 38683 - 38689
(2021/12/20)
-
- Benzoheterocyclic Oxime Carbamates Active against Mycobacterium tuberculosis: Synthesis, Structure-Activity Relationship, Metabolism, and Biology Triaging
-
Screening of a library of small polar molecules against Mycobacterium tuberculosis (Mtb) led to the identification of a potent benzoheterocyclic oxime carbamate hit series. This series was subjected to medicinal chemistry progression underpinned by structure-activity relationship studies toward identifying a compound for proof-of-concept studies and defining a lead optimization strategy. Carbamate and free oxime frontrunner compounds with good stability in liver microsomes and no hERG channel inhibition liability were identified and evaluated in vivo for pharmacokinetic properties. Mtb-mediated permeation and metabolism studies revealed that the carbamates were acting as prodrugs. Toward mechanism of action elucidation, selected compounds were tested in biology triage assays to assess their activity against known promiscuous targets. Taken together, these data suggest a novel yet unknown mode of action for these antitubercular hits.
- Van Der Westhuyzen, Renier,Mabhula, Amanda,Njaria, Paul M.,Müller, Rudolf,Ngumbu Muhunga, Denis,Taylor, Dale,Lawrence, Nina,Njoroge, Mathew,Brunschwig, Christel,Moosa, Atica,Singh, Vinayak,Rao, Srinivasa P.S.,Manjunatha, Ujjini H.,Smith, Paul W.,Warner, Digby F.,Street, Leslie J.,Chibale, Kelly
-
supporting information
p. 9444 - 9457
(2021/07/19)
-
- Photoinduced remote heteroaryl migration accompanied by cyanoalkylacylation in continuous flow
-
A photoinduced 1,4-heteroaryl migration from a carbon center to a nitrogen center accompanied by a cyanoalkylacylation of heterocyclic-substituted azidyl homoallylic alcohols and cycloketone oxime esters has been described. This simple and powerful protoc
- Duan, Xiu,Guo, Kai,Liu, Jie,Ma, Can-Liang,Qin, Long-Zhou,Qiu, Jiang-Kai,Sun, Qi,Wu, Meng-Yu,Yuan, Xin,Zhang, Xin-Peng,Zhu, Shan-Shan
-
supporting information
p. 8916 - 8921
(2021/11/27)
-
- New synthesis of 2-aroylbenzothiazolesviametal-free domino transformations of anilines, acetophenones, and elemental sulfur
-
A new synthesis of 2-aroylbenzothiazolesviaiodine-promoted domino transformations of anilines, acetophenones, and elemental sulfur was demonstrated. The highlights of this tandem synthesis are (1) easily available anilines and acetophenones as feedstock;
- Doan, Khang V.,Doan, Son H.,Huynh, Tien V.,Luong, Ngoc T. K.,Nguyen, Duyen T. P.,Nguyen, Tung T.,Phan, Nam T. S.
-
p. 18423 - 18433
(2020/06/08)
-
- NCS/TBHP promoted C2 arylation of benzothiazoles with aldehydes in DMSO
-
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.
- Xu, Wen-Xiu,Ye, Fei-Xia,Liu, Xing-Hai,Weng, Jian-Quan
-
-
- Preparation method of C2 substituted 2H-benzothiazole acylation derivative
-
The invention discloses a preparation method of a C2 substituted 2Hbenzothiazole acylation derivative. The preparation method comprises the following steps: mixing 2Hbenzothiazole with substituted methyl benzene, adding an oxidizing agent K2S2O8, reacting in an air atmosphere, carrying out TLC (Thin Layer Chromatography) monitoring until the reaction is finished, and separating and purifying the reaction solution to obtain the C2 substituted 2Hbenzothiazole acylation derivative. By the adoption of the technology, K2S2O8 serves as an oxidizing agent, the C2-substituted 2Hbenzothiazole acylationderivative is synthesized through a heating reaction in the air atmosphere, and the method is simple in catalytic system, good in product yield, wide in substrate range and suitable for application and popularization.
- -
-
Paragraph 0014-0015
(2020/11/22)
-
- Iodine- And TBHP-Promoted Acylation of Benzothiazoles under Metal-Free Conditions
-
A simple protocol for the synthesis of 2-acylbenzothiazoles using aryl ketones and benzothiazoles in the presence of I 2and TBHP is described. Acylation of the benzothiazoles is achieved through a sequence involving oxidation of the aryl ketone to an aryl glyoxal, ring-opening of the benzothiazole followed by condensation of the amino group with the aryl glyoxal, cyclization and oxidation. The method avoids the use of metals and toxic solvents. In addition, this protocol has the advantage of broad scope and provides good to excellent product yields.
- Wang, Bin,Zhang, Qianwei,Guo, Zhongqi,Ablajan, Keyume
-
p. 3058 - 3064
(2020/08/28)
-
- Iron-catalyzed acylation-functionalization of unactivated alkenes with aldehydes
-
Herein, an iron-catalyzed acylation-functionalization of unactivated alkenes with aldehydes via distal group ipso-migration is reported. This strategy overcame the energy barrier and reversibility in the difunctionalization of unactivated alkenes with nuc
- Tian, Tian,Wang, Xin,Lv, Leiyang,Li, Zhiping
-
supporting information
p. 14637 - 14640
(2020/12/02)
-
- Overcoming Electron-Withdrawing and Product-Inhibition Effects by Organocatalytic Aerobic Oxidation of Alkylpyridines and Related Alkylheteroarenes to Ketones
-
An organocatalyzed aerobic benzylic C-H oxidation of alkyl and aryl heterocycles has been developed. This transition metal-free method is able to overcome the electron-withdrawing effect as well as product-inhibition effects in heterobenzylic radical oxidation. A variety of ketones bearing N-heterocyclic groups could be prepared under relatively mild conditions with moderate to high yields.
- Wang, Hua,Liu, Jie,Qu, Jian-Ping,Kang, Yan-Biao
-
p. 3942 - 3948
(2020/03/23)
-
- Aroylation of Electron-Rich Pyrroles under Minisci Reaction Conditions
-
The development of Minisci acylation on electron-rich pyrroles under silver-free neutral conditions has been reported featuring the regioselective monoacylation of (NH)-free pyrroles. Unlike conventional Minisci conditions, the avoidance of any acid that could result in the polymerization of pyrroles was the key to success. The umpolung reactivity of the nucleophilic acyl radical, generated in situ from arylglyoxylic acid, could help explain the mechanism of product formation with electron-rich pyrroles. Alternatively, the nucleophilic substitution of the acyl radical on the electron-deficient pyrrole radical cation is proposed.
- Laha, Joydev K.,Kaur Hunjan, Mandeep,Hegde, Shalakha,Gupta, Anjali
-
p. 1442 - 1447
(2020/02/22)
-
- Synthesis of N-Formyl-2-benzoyl Benzothiazolines, 2-Substituted Benzothiazoles, and Symmetrical Disulfides from N-Phenacylbenzothiazolium Bromides
-
An unusual aerobic hydrolysis-cascade reaction has been developed with N-phenacylbenzothiazolium bromides by treatment with organic and inorganic base. The corresponding N-formyl-2-benzoyl benzothiazoline and 2-substituted benzothiazole products were obta
- Sahoo, Subas Chandra,Pan, Subhas Chandra
-
p. 6208 - 6212
(2019/08/21)
-
- A convenient synthesis of 2-acyl benzothiazoles/thiazoles from benzothiazole/thiazole and N,N'-carbonyldiimidazole activated carboxylic acids
-
A convenient and efficient strategy for the synthesis of 2-acyl benzothiazoles/thiazoles has been developed. The treatment of benzothiazole/thiazole with allylic Grignard reagents readily generates the corresponding 2-Grignard reagents, which is followed by a reaction with N,N'-carbonyldiimidazole activated carboxylic acids to afford various 2-acyl benzothiazoles/thiazoles products. The synthetic method is applicable to a wide array of carboxylic acids and allows easy access to 2-acyl benzothiazoles/thiazoles with considerable yields under mild reaction conditions.
- Huang, Tonghui,Wu, Xin,Yu, Yongbo,An, Lin,Yin, Xiaoxing
-
p. 1667 - 1670
(2019/06/04)
-
- Catalytic C?H/C?F Coupling of Azoles and Acyl Fluorides
-
A method for the palladium/copper-catalyzed direct acylation of azoles with acyl fluorides is described. This study reports the first examples of acyl fluorides being used as acylation reagents in transition-metal-catalyzed aromatic C?H bond functionalization reactions. Depending on the reaction temperature, decarbonylative coupling may also occur. Mechanistic studies suggest that the cleavage of the aromatic C?H bond, promoted by a copper-phosphine species, is not the rate-limiting step of this acylation.
- Ogiwara, Yohei,Iino, Yurika,Sakai, Norio
-
supporting information
p. 6513 - 6516
(2019/04/27)
-
- Method for simply and conveniently synthesizing heterocyclic aryl ketone compound
-
The invention discloses a method for simply and conveniently synthesizing a heterocyclic aryl ketone compound, and belongs to the technical field of the organic chemistry. The method comprises the following steps: using a benzyl heterocyclic compound as a reaction raw material, in a polar solvent, heating and reacting in an oxygen atmosphere, to obtain a multi-substituted ketone compound. The method is capable of using molecular oxygen as an oxidizing agent, green and environmental, and capable of preparing ketone by directly promoting selective oxidation and functionalization of a Csp3-H bond, and broadening a synthetic method for the ketone compound.
- -
-
Paragraph 0046; 0047; 0048
(2019/01/23)
-
- Aniline ortho C?H Sulfuration/Cyclization with Elemental Sulfur for Efficient Synthesis of 2-Substituted Benzothiazoles under Metal-Free Conditions
-
A three-component synthesis of 2-substituted benzothiazoles from aryl amines, elemental sulfur and styrenes or aryl acetylenes in 1-methylpyrrolidin-2-one (NMP) is described. Two C?S and one C?N bonds were selectively formed in one-pot under metal-free conditions. (Figure presented.).
- Jiang, Jingjing,Li, Guozheng,Zhang, Feng,Xie, Hao,Deng, Guo-Jun
-
p. 1622 - 1627
(2018/03/07)
-
- Metal-Free Halogen(I) Catalysts for the Oxidation of Aryl(heteroaryl)methanes to Ketones or Esters: Selectivity Control by Halogen Bonding
-
Metal-free halogen(I) catalysts were used for the selective oxidation of aryl(heteroaryl)methanes [C(sp3)?H] to ketones [C(sp2)=O] or esters [C(sp3)?O]. The synthesis of ketones was performed with a catalytic amount of NBS in DMSO solvent. Experimental studies and density functional theory (DFT) calculations supported the formation of halogen bonding (XB) between the heteroarene and N-bromosuccinimide, which enabled imine–enamine tautomerism of the substrates. No additional activator was required for this crucial step. Isotope-labeling and other supporting experiments suggested that a Kornblum-type oxidation with DMSO and aerobic oxygenation with molecular oxygen took place simultaneously. A background XB-assisted electron transfer between the heteroarenes and halogen(I) catalysts was responsible for the formation of heterobenzylic radicals and, thus, the aerobic oxygenation. For selective acyloxylation (ester formation), a catalytic amount of iodine was employed with tert-butyl hydroperoxide in aliphatic carboxylic acid solvent. Several control reactions, spectroscopic studies, and Time-Dependent Density Functional Theory (TD–DFT) calculations established the presence of acetyl hypoiodite as an active halogen(I) species in the acetoxylation process. With the help of a selectivity study, for the first time we report that the strength of the XB interaction and the frontier orbital mixing between the substrates and acyl hypoiodites determined the extent of the background electron-transfer process and, thus, the selectivity of the reaction.
- Guha, Somraj,Sekar, Govindasamy
-
p. 14171 - 14182
(2018/09/10)
-
- Silver-mediated 2-arylation/alkylation/acylation of benzothiazoles with aldehydes in water
-
An efficient and environmentally benign method was developed for the facile synthesis of various 2-aryl and 2-alkyl substituted benzothiazoles in moderate to good yields, using a silver-mediated redox condensation of benzothiazoles and aldehydes in water. Furthermore, this method is also applicable to prepare 2-acyl benzothiazoles.
- Hua, Min,Wang, Chunqin,Liu, Qixing,Chen, Danyi,Fu, Hao,Zhou, Haifeng
-
p. 1226 - 1237
(2018/08/06)
-
- Acyl Radicals from Terminal Alkynes: Photoredox-Catalyzed Acylation of Heteroarenes
-
A photoredox-mediated acylation reaction of electron deficient heteroarenes with terminal alkynes is reported. The method relies on oxidative cleavage of phenylacetylenes for generation of acyl radicals as a key enabling feature. The reaction is regiosele
- Sultan, Shaista,Rizvi, Masood Ahmad,Kumar, Jaswant,Shah, Bhahwal Ali
-
supporting information
p. 10617 - 10620
(2018/07/31)
-
- Controllable assembly of the benzothiazole framework using a CC triple bond as a one-carbon synthon
-
A concise and efficient protocol to assemble diverse benzothiazole derivatives in high yields was provided via copper catalyzed tandem cyclization with o-haloanilines, elemental sulfur and terminal alkynes as raw materials. In this protocol, C atoms on the CC triple bond were controllably involved in the construction of the benzothiazole framework and multiple carbon-heteroatom bonds through divergent routes.
- Huang, Yubing,Yan, Donghao,Wang, Xu,Zhou, Peiqi,Wu, Wanqing,Jiang, Huanfeng
-
p. 1742 - 1745
(2018/02/21)
-
- Visible-Light-Triggered, Metal- and Photocatalyst-Free Acylation of N-Heterocycles
-
A photoinduced acylation of N-heterocycles is explored. This visible-light triggered reaction occurs not only under extremely mild reaction conditions, but also does not require the presence of a photosensitizer. The mechanistic studies suggest formation of EDA complexes prompt to harness the energy from visible-light. Compatibility with a large panel of α-keto acids as acyl precursors and an array of N-heterocycles clearly showcase the synthetic potential of this handy and green acylation protocol. (Figure presented.).
- Guillemard, Lucas,Colobert, Fran?oise,Wencel-Delord, Joanna
-
supporting information
p. 4184 - 4190
(2018/09/25)
-
- Visible-Light-Initiated, Photocatalyst-Free Decarboxylative Coupling of Carboxylic Acids with N-Heterocycles
-
A general and efficient protocol for direct C-H alkylation and acylation of N-heterocycles, using readily accessible carboxylic acids as radical precursors under visible-light irradiation without a photocatalyst and an additional acid additive, has been d
- Zhang, Xiao-Yu,Weng, Wei-Zhi,Liang, Hao,Yang, Hua,Zhang, Bo
-
supporting information
p. 4686 - 4690
(2018/08/09)
-
- Ball-milling synthesized hydrotalcite supported Cu-Mn mixed oxide under solvent-free conditions: An active catalyst for aerobic oxidative synthesis of 2-acylbenzothiazoles and quinoxalines
-
A rapid solvent-free ball-milling method was developed to prepare a hydrophobic hydrotalcite supported Cu-Mn mixed oxide catalyst (Cu-Mn/HT). The mechanochemically prepared catalyst exhibited high catalytic activity and recyclability towards the aerobic synthesis of 2-acylbenzothiazoles and quinoxalines in green medium ethanol compared with the ones synthesized via grinding and wet-impregnation. Moreover, control experiments showed that the catalyst was successfully used in green oxidative esterification and coupling as well. Cu-Mn/HT was characterized by BET, ICP, XRD, XPS, SEM and TEM, which indicated that more surface oxygen vacancies and formed CuMn2O4 species on HT might contribute to the catalytic activity.
- Meng, Xu,Bi, Xiuru,Yu, Chaoying,Chen, Gexin,Chen, Baohua,Jing, Zhenqiang,Zhao, Peiqing
-
supporting information
p. 4638 - 4644
(2018/10/23)
-
- Elemental sulfur mediated 2-substituted benzothiazole formation from 2-aminobenzenethiols and arylacetylenes or styrenes under metal-free conditions
-
An oxidative cyclization of 2-aminothiophenols and arylacetylenes or styrenes for the synthesis of 2-alkylbenzothiazoles and 2-acylbenzothiazoles has been developed. Elemental sulfur was used as the effective oxidant to give the corresponding product in g
- Li, Guozheng,Jiang, Jingjing,Zhang, Feng,Xiao, Fuhong,Deng, Guo-Jun
-
p. 10024 - 10028
(2017/12/26)
-
- Palladium(II)/N-heterocyclic carbene-catalyzed direct C-H acylation of heteroarenes with N-acylsaccharins
-
N-Acylsaccharin represents a facile acyl group transfer agent to heteroarenes in the presence of Pd(II)/NHC complexes appended with a pyrene unit. Catalytic acylation of heteroarenes was enhanced by the noncovalent interaction between the pyrene unit and
- Karthik, Shanmugam,Gandhi, Thirumanavelan
-
p. 5486 - 5489
(2017/11/06)
-
- Water-controlled selective preparation of α-mono or α,α′-dihalo ketones: Via catalytic cascade reaction of unactivated alkynes with 1,3-dihalo-5,5-dimethylhydantoin
-
The control of a reaction that can produce multiple products from the same starting material is a highly attractive and challenging concept in organic synthesis. An efficient protocol for the selective synthesis of α-mono or α,α′-dihalo ketones via a water-controlled three-component thiourea-catalyzed cascade reaction of unactivated alkynes, 1,3-dihalo-5,5-dimethylhydantoin and water has been developed. α-Monohaloketones were obtained in aqueous acetone at 45 °C; conversely, α,α′-dihalo ketones were formed with pure water as the sole solvent at room temperature.
- Wu, Chao,Xin, Xiu,Fu, Zhi-Min,Xie, Long-Yong,Liu, Kai-Jian,Wang, Zheng,Li, Wenyi,Yuan, Zhi-Hui,He, Wei-Min
-
p. 1983 - 1989
(2017/06/09)
-
- Co/NHPI-mediated aerobic oxygenation of benzylic C-H bonds in pharmaceutically relevant molecules
-
A simple cobalt(ii)/N-hydroxyphthalimide catalyst system has been identified for selective conversion of benzylic methylene groups in pharmaceutically relevant (hetero)arenes to the corresponding (hetero)aryl ketones. The radical reaction pathway tolerates electronically diverse benzylic C-H bonds, contrasting recent oxygenation reactions that are initiated by deprotonation of a benzylic C-H bond. The reactions proceed under practical reaction conditions (1 M substrate in BuOAc or EtOAc solvent, 12 h, 90-100 °C), and they tolerate common heterocycles, such as pyridines and imidazoles. A cobalt-free, electrochemical, NHPI-catalyzed oxygenation method overcomes challenges encountered with chelating substrates that inhibit the chemical reaction. The utility of the aerobic oxidation method is showcased in the multigram synthesis of a key intermediate towards a drug candidate (AMG 579) under process-relevant reaction conditions.
- Hruszkewycz, Damian P.,Miles, Kelsey C.,Thiel,Stahl, Shannon S.
-
p. 1282 - 1287
(2017/02/10)
-
- Metal-free oxidative carbonylation on enaminone CC bond for the cascade synthesis of benzothiazole-containing vicinal diketones
-
The cascade reactions between enaminones and o-aminothiophenols have been implemented to provide unprecedented vicinal diketones containing benzothiazole structures. The construction of the products has been realized under metal-free conditions via carbon
- Wan, Jie-Ping,Zhou, Youyi,Liu, Yunyun,Sheng, Shouri
-
supporting information
p. 402 - 405
(2016/01/30)
-
- Synthesis of 2-Keto(hetero)aryl Benzox(thio)azoles through Base Promoted Cyclization of 2-Amino(thio)phenols with α,α-Dihaloketones
-
An interesting base-promoted protocol for the synthesis of 2-keto(hetero)aryl benzox(thi)azoles has been developed. Starting from commercially available 2-amino(thio)phenols and α,α-dihaloketones, moderate to good yields of the corresponding heterocycles can be achieved. Notably, only EtNH2 was required as the promoter here, and the reaction can be easily performed on a large scale.
- Jiang, Jun,Zou, Huaxu,Dong, Qizhi,Wang, Ruijia,Lu, Linghui,Zhu, Yonggang,He, Weimin
-
-
- Catalytic Aerobic Photo-oxidation of a Methyl Group on a Heterocycle to Produce an Aldehyde via Homolytic C-I Bond Cleavage caused by Irradiation with Visible Light
-
A new catalytic method was developed for photo-oxidizing the methyl group on aromatic heterocycles such as benzothiazole, benzoxazole, and quinoline to produce the corresponding aldehyde. This is the first report of the metal-free catalytic synthesis of benzothiazole-2-carboxaldehydes using molecular oxygen as the terminal oxidant.
- Nagasawa,Tachikawa,Yamaguchi,Tada,Miura,Itoh
-
supporting information
p. 178 - 182
(2016/02/14)
-
- Copper-II mediated tandem reaction between aromatic ketones and 2-aminobenzenethiol for the synthesis of 2-aroylbenzothiazoles
-
A novel copper(II) mediated tandem reaction was developed for the synthesis of 2-aroylbenzothiazoles from readily available aryl-alkyl ketones in the presence of oxygen in ethanol. This method is mild, operationally simple, makes the use of inexpensive Cu
- Mali, Jaishree K.,Mali, Devidas A.,Telvekar, Vikas N.
-
supporting information
p. 2324 - 2326
(2016/05/10)
-
- Iodine-promoted oxidative amidation of terminal alkenes - Synthesis of α-ketoamides, benzothiazoles, and quinazolines
-
A novel metal-free strategy for oxidative amidation of terminal alkenes by using I2/DMSO for the synthesis of α- ketoamides has been developed. Intriguingly, the use of tertbutylhydroperoxide (TBHP) as co-oxidant can facilitate the synthesis of α-ketoamides at room temperature without any solvent, thereby making it a green protocol. The reaction with primary amines can be easily achieved by using SeO2 as an oxidizing agent. Besides, the scope of the method was also extended to the synthesis of benzothiazolines and quinazolines.
- Deshidi, Ramesh,Devari, Shekaraiah,Shah, Bhahwal Ali
-
supporting information
p. 1428 - 1432
(2015/03/04)
-
- Pd-Catalyzed Csp2-H Functionalization of Heteroarenes via Isocyanide Insertion: Concise Synthesis of Di-(Hetero)Aryl Ketones and Di-(Hetero)Aryl Alkylamines
-
We report herein an efficient Pd-catalyzed direct C-H bond functionalization of heteroarenes via an isocyanide insertion strategy for the synthesis of di-(hetero)aryl ketones and di-(hetero)aryl alkylamines. The methodology involves a three component reaction between an azole, a haloarene and an isocyanide resulting in the formation of an imine, which in turn is either hydrolyzed or reduced to get the desired product.
- Sharma, Upendra K.,Sharma, Nandini,Xu, Jun,Song, Gonghua,Van Der Eycken, Erik V.
-
supporting information
p. 4908 - 4912
(2015/03/30)
-
- Cobalt-Catalyzed Decarboxylative 2-Benzoylation of Oxazoles and Thiazoles with α-Oxocarboxylic Acids
-
Cobalt-catalyzed decarboxylative cross-coupling of oxazoles and thiazoles with α-oxocarboxylic acids was developed through an sp2 C-H bond functionalization process. This work represents the first example of cobalt-catalyzed decarboxylative C-H
- Yang, Ke,Chen, Xinyong,Wang, Yuqi,Li, Wanqing,Kadi, Adnan A.,Fun, Hoong-Kun,Sun, Hao,Zhang, Yan,Li, Guigen,Lu, Hongjian
-
p. 11065 - 11072
(2015/11/18)
-
- Rhodium Catalyzed Asymmetric Hydrogenation of 2-Pyridine Ketones
-
Catalyzed by [Rh(COD)Binapine]BF4, the asymmetric hydrogenation of 2-pyridine ketones has been achieved with excellent enantioselectivities (enantiomeric excesses up to 99%) under mild conditions. This method is suitable for various kinds of 2-pyridine ketones and their derivatives. A number of enantiomerically pure chiral 2-pyridine-aryl/alkyl alcohols were prepared through hydrogenation, which can be used directly in organic synthesis.
- Yang, Hailong,Huo, Ningning,Yang, Ping,Pei, Hao,Lv, Hui,Zhang, Xumu
-
supporting information
p. 4144 - 4147
(2015/09/15)
-
- Concise Access to 2-Aroylbenzothiazoles by Redox Condensation Reaction between o-Halonitrobenzenes, Acetophenones, and Elemental Sulfur
-
A wide range of 2-aroylbenzothiazoles 3 including some pharmacologically relevant derivatives can be obtained in high yields by simply heating o-halonitrobenzenes 1, acetophenones 2, elemental sulfur, and N-methylmorpholine. This three-component nitro methyl coupling was found to occur in an excellent atom-, step-, and redox-efficient manner in which elemental sulfur played the role of nucleophile building block and redox moderating agent to fulfill electronic requirements of the global reaction. (Chemical Equation Presented).
- Nguyen, Thanh Binh,Pasturaud, Karine,Ermolenko, Ludmila,Al-Mourabit, Ali
-
p. 2562 - 2565
(2015/06/02)
-
- Chemoselective copper-catalyzed acylation of benzothiazoles with aryl methyl ketones
-
A copper(I) iodide-catalyzed, highly efficient acylation of benzothiazoles with aryl methyl ketones as carbonyl sources under a nitrogen atmosphere was developed. This is an unprecedented protocol and an extremely efficient method for the selective synthesis of 2-acylbenzothiazoles from commercially available, cheap starting materials with excellent chemoselectivity, good functional group tolerability and high turnover numbers (up to 14,200); also scaling up to 160mmol without loss of the efficiency is possible. A variety of 2-acylbenzothiazoles was smoothly prepared in good to excellent yields from aryl methyl ketones and benzothiazoles by a one-pot domino protocol of combined sp3 C-H oxidation, ring opening, and condensation.
- Feng, Qiang,Song, Qiuling
-
supporting information
p. 2445 - 2452
(2014/10/15)
-
- Synthesis of 2-Acylbenzothiazoles via the Cu(OTf)2-Catalyzed tandem reaction of β,β-Dihalidestyrenes with 2,2′- Disulfanediyldianilines
-
A new method has been developed for the one-pot construction of 2-acylbenzothiazoles via the Cu(OTf)2-catalyzed tandem reaction of β,β-dihalidestyrenes with 2,2′-disulfane-diyldianilines. A variety of different dihalidestyrenes and diphenyldisulfanes were efficiently converted into the corresponding 2-acylbenzothiszole derivatives in the presence of Cu(OTf)2. Most importantly, this protocol allowed for the long chain 1,1-dibromohept-1-ene to be converted into the corresponding 2-hexylbenzo[d]thiazole in moderate yield. Georg Thieme Verlag Stuttgart, New York.
- Zhou, Zeng-Le,Fang, Tao,Tang, Ri-Yuan,Zhang, Xing-Guo,Deng, Chen-Liang
-
supporting information
p. 255 - 260
(2014/02/14)
-
- Iron catalyzed efficient synthesis of 2-arylbenzothiazoles from benzothiazole and olefins using environmentally benign molecular oxygen as oxidant
-
A novel protocol for iron catalyzed arylation of benzothiazole with olefins has been developed using molecular oxygen as a greener oxidant. The reaction worked smoothly using inexpensive and easily available iron as a catalyst for the synthesis of 2-arylbenzothiazole derivatives in good to excellent yields.
- Khemnar, Ashok B.,Bhanage, Bhalchandra M.
-
p. 8939 - 8942
(2014/03/21)
-