Cheng-chu Zeng

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Organization: Beijing University of Technology

Department: College of Life Science and Bioengineering

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TOPICS

Organic Chemistry

C-H Activation

Chemicals
References

Electrocatalytic Minisci Acylation Reaction of N-Heteroarenes Mediated by NH4I

Co-reporter:Qing-Qing Wang, Kun Xu, Yang-Ye Jiang, Yong-Guo Liu, Bao-Guo Sun, and Cheng-Chu Zeng

Organic Letters October 20, 2017 Volume 19(Issue 20) pp:5517-5517

Publication Date(Web):October 2, 2017

DOI:10.1021/acs.orglett.7b02589

An electrochemical C–H acylation of electron-deficient N-heteroarenes with α-keto acids is reported. This first electrochemical Minisci acylation reaction proceeded using NH4I as a redox catalyst. A broad N-heteroarene scope and high functional group tolerance are observed. Selective monoacylation of N-heteroarenes is achieved via control of acyl radical at a low concentration. The results of cyclic voltammetry and control experiments disclose that the electrogenerated I2 is likely the active species to initiate the oxidative decarboxylation of carboxylate anion via an acyl hypoiodite intermediate. The electrochemical Minisci acylation provides a straightforward approach for the late-stage functionalization of pharmacophores.

Selective electrochemical CO bond cleavage of β-O-4 lignin model compounds mediated by iodide ion

Co-reporter:Wei-Jing Gao, Chiu Marco Lam, Bao-Guo Sun, R. Daniel Little, Cheng-Chu Zeng

Tetrahedron 2017 Volume 73, Issue 17(Issue 17) pp:

Publication Date(Web):27 April 2017

DOI:10.1016/j.tet.2017.03.027

The electrochemically oxidative cleavage of lignin β-O-4 model compounds mediated by iodide ion has been studied. The results indicate that electrolytic conditions play a predominant role in determining the distribution of cleavage products. The preparative-scale electrolysis proceeds in a simple undivided cell, employing a catalytic amount of NaI as the redox mediator and supporting electrolyte in methanol. Under these conditions, the CβO bond is selectively cleaved with 2,2-dimethoxy-2-arylacetaldehyde being the main product. In some cases, the reaction gives a good yield of cleavaged products. The results further demonstrate that the indirect electrolysis mediated by halide is a versatile approach for chemical transformation.Download high-res image (92KB)Download full-size image

Electrochemical C–H functionalization and subsequent C–S and C–N bond formation: paired electrosynthesis of 3-amino-2-thiocyanato-α,β-unsaturated carbonyl derivatives mediated by bromide ions

Co-reporter:Li-Shuo Kang, Mi-Hai Luo, Chiu Marco Lam, Li-Ming Hu, R. Daniel Little and Cheng-Chu Zeng

Green Chemistry 2016 vol. 18(Issue 13) pp:3767-3774

Publication Date(Web):30 Mar 2016

DOI:10.1039/C6GC00666C

An efficient paired electrosynthesis involving C–H functionalization and subsequent C–S and C–N bond formation for the assembly of valuable 3-amino-2-thiocyanato-α,β-unsaturated carbonyl derivatives has been developed. In the paired electrolysis, the amino and thiocyanato moieties originate from a single reagent or a combination of ammonium acetate and potassium isocyanate. The chemistry proceeds in a simple undivided cell employing a sub-stoichiometric amount of NH4Br that serves both as an inner sphere type redox catalyst and a supporting electrolyte; in this manner an additional conducting salt is not required. The reaction also works using a catalytic amount of NH4Br. Cyclic voltammetry and the results of control experiments demonstrate that the reaction proceeds via an anodically initiated C–H functionalization of the 1,3-dicarbonyl substrates that occurs via the electrochemical oxidation of bromide and simultaneous cathodic reduction of ammonium ions.

Electrochemical analysis of the triarylimidazole-type organic redox catalysts: Chemical stability and homogeneous electron transfer kinetics for the oxidation of 4-methoxybenzyl alcohol

Co-reporter:Kui-Yong Zhang, Nan-ning Lu, Seung Joon Yoo, Li-Ming Hu, R.Daniel Little, Cheng-Chu Zeng

Electrochimica Acta 2016 Volume 199() pp:357-365

Publication Date(Web):1 May 2016

DOI:10.1016/j.electacta.2016.02.132

•The current response and reversibility of triarylimidazole-type redox catalysts differs depending upon the nature of the conducting salt and solvent, as well as the concentration of the supporting electrolyte.•The best reversibility for the triarylimidazoles could be achieved in 0.05 M LiClO4/CH3CN.•The electrochemical catalytic efficiency was found to depend upon the peak potential difference between a redox catalyst and the substrate.Triarylimidazoles have emerged as novel and useful organic redox catalysts as a result of their straightforward synthesis and tunable oxidation potential. Herein we describe an investigation of the effects of supporting electrolyte and solvent on the chemical reversibility of the triarylimidazole redox couple. Next, the homogeneous electron transfer rate for three triarylimidazole mediators toward the oxidation of 4-methoxybenzyl alcohol was estimated using cyclic voltammetry. The results indicate that the concentration and composition of the conducting salts, especially of the anion, affect the electrochemical performance of the triarylimidazole. Kinetic studies reveal that the smaller the peak potential difference between a mediator and the substrate, the larger the catalytic current and the pseudo first-order homogeneous rate constant.

Electrochemical synthesis of benzoxazoles mediated by 2,3-dichloro-5,6-dicyano-p-hydroquinone (DDH) as a redox catalyst

Co-reporter:Li-Shuo Kang, Huan-lan Xiao, Cheng-Chu Zeng, Li-Ming Hu, R. Daniel Little

Journal of Electroanalytical Chemistry 2016 Volume 767() pp:13-17

Publication Date(Web):15 April 2016

DOI:10.1016/j.jelechem.2015.12.051

•The first report of the electrochemical cyclization of Schiff bases leading to benzoxazoles using DDH as a mediator.•The presence of 2,6-lutidine facilitiates the deprotonation.•The chemistry was performed in a beaker type undivided cell under constant current electrolysis conditions.A novel electrochemical strategy for the efficient synthesis of benzoxazoles has been developed. The chemistry is performed in a beaker-type undivided cell under constant current electrolysis conditions, utilizing 2,3-dichloro-5,6-dicyano-p-hydroquinone (DDH) as a redox catalyst.

Electrochemical Oxidative Amination of Sodium Sulfinates: Synthesis of Sulfonamides Mediated by NH4I as a Redox Catalyst

Co-reporter:Yang-ye Jiang, Qing-Qing Wang, Sen Liang, Li-Ming Hu, R. Daniel Little, and Cheng-Chu Zeng

The Journal of Organic Chemistry 2016 Volume 81(Issue 11) pp:4713-4719

Publication Date(Web):May 3, 2016

DOI:10.1021/acs.joc.6b00615

An efficient protocol for the synthesis of sulfonamides via the electrochemical oxidative amination of sodium sulfinates has been developed. The chemistry proceeds in a simple undivided cell employing a substoichiometric amount of NH4I that serves both as a redox catalyst and a supporting electrolyte; in this manner additional conducting salt is not required. A wide range of substrates, including aliphatic or aromatic secondary and primary amines, as well as aqueous ammonia, proved to be compatible with the protocol. Scale-up was possible, thereby demonstrating the practicality of the approach. The electrolytic process avoids the utilization of external oxidants or corrosive molecular iodine and therefore represents an environmentally benign means by which to achieve the transformation.

Electrochemically Oxidative α-C–H Functionalization of Ketones: A Cascade Synthesis of α-Amino Ketones Mediated by NH4I

Co-reporter:Sen Liang, Cheng-Chu Zeng, Hong-Yu Tian, Bao-Guo Sun, Xu-Gang Luo, and Fa-zheng Ren

The Journal of Organic Chemistry 2016 Volume 81(Issue 23) pp:11565-11573

Publication Date(Web):November 4, 2016

DOI:10.1021/acs.joc.6b01595

An efficient electrochemical protocol for the synthesis of α-amino ketones via the oxidative cross-dehydrogenative coupling of ketones and secondary amines has been developed. The electrochemistry performs in a simple undivided cell using NH4I as a redox catalyst and a cheap graphite plate as electrodes under constant current conditions. Gram-scale reaction demonstrates the practicality of the protocol. The reaction is proposed to procced through an initial α-iodination of ketone, followed by a nucleophilic substitution of amines.

Electrocatalytic Aziridination of Alkenes Mediated by n-Bu4NI: ARadical Pathway

Co-reporter:Jie Chen, Wei-Qing Yan, Chiu Marco Lam, Cheng-Chu Zeng, Li-Ming Hu, and R. Daniel Little

Organic Letters 2015 Volume 17(Issue 4) pp:986-989

Publication Date(Web):February 5, 2015

DOI:10.1021/acs.orglett.5b00083

Efficient electrocatalytic aziridination of alkenes has been achieved for the first time. A structurally broad range of aziridines was easily accessed using an undivided cell operated at constant current and mediated by a catalytic quantity of n-Bu4NI. The electrocatalytic reaction also proceeded in the absence of additional conducting salt. The aziridination is proposed to follow a radical mechanism.

Design and synthesis of 5-chloro-2-hydroxy-3-triazolylbenzoic acids as HIV integrase inhibitors

Co-reporter:Jie Chen;Cheng-Fu Liu;Cheng-Wen Yang

Medicinal Chemistry Research 2015 Volume 24( Issue 7) pp:2950-2959

Publication Date(Web):2015 July

DOI:10.1007/s00044-015-1325-9

A series of potential HIV-1 integrase inhibitors based on 5-chloro-2-hydroxy-3-triazolylbenzoic acid scaffold was designed and synthesized. Some of these compounds exhibit potent inhibitory activities at micromolar concentrations against HIV-1 integrase in the 3′-end processing and the strand transfer step.

Aromatic C–H Bond Functionalization Induced by Electrochemically in Situ Generated Tris(p-bromophenyl)aminium Radical Cation: Cationic Chain Reactions of Electron-Rich Aromatics with Enamides

Co-reporter:Long-Ji Li, Yang-Ye Jiang, Chiu Marco Lam, Cheng-Chu Zeng, Li-Ming Hu, and R. Daniel Little

The Journal of Organic Chemistry 2015 Volume 80(Issue 21) pp:11021-11030

Publication Date(Web):October 7, 2015

DOI:10.1021/acs.joc.5b02222

An effective Friedel–Crafts alkylation reaction of electron-rich aromatics with N-vinylamides, induced by electrochemically in situ-generated TBPA radical cation, has been developed; the resulting adducts are produced in good to excellent yields. In the “ex-cell” type electrolysis, TBPA is transformed to its oxidized form in situ and subsequently employed as an electron transfer reagent to initiate a cationic chain reaction. An easily recoverable and reusable polymeric ionic liquid–carbon black (PIL–CB) composite was also utilized as a supporting electrolyte for the electrochemical generation of TBPA cation radical, without sacrificing efficiency or stability after four electrolyses. Cyclic voltammetry analysis and the results of control experiments demonstrate that the reaction of electron-rich aromatics and N-vinylamides occurs via a cationic chain reaction, which takes place though an oxidative activation of a C–H bond of electron-rich aromatics instead of oxidation of the N-vinylamide as previously assumed.

Electrochemically Induced Ring-Opening/Friedel–Crafts Arylation of Chalcone Epoxides Catalyzed by a Triarylimidazole Redox Mediator

Co-reporter:Nan-ning Lu, Ni-tao Zhang, Cheng-Chu Zeng, Li-Ming Hu, Seung Joon Yoo, and R. Daniel Little

The Journal of Organic Chemistry 2015 Volume 80(Issue 2) pp:781-789

Publication Date(Web):December 2, 2014

DOI:10.1021/jo5022184

The indirect anodic oxidation of chalcone epoxides in the presence of electron-rich heteroarenes mediated by a triarylimidazole (Med) was investigated by cyclic voltammetry (CV) and controlled potential electrolysis. The CV results indicate that a homogeneous electron transfer between Med•+ and chalcone epoxides is facilitated by an electron-rich heteroarene that serves as an arylation reagent. The preparative scale electrolysis generated epoxide-ring-opened/Friedel–Crafts arylation products in moderate to good yields. The fact that only a catalytic amount of charge was required suggests that Med•+ initiates a chain reaction. In addition, overoxidation of the products is avoided even though their oxidation potential is less than that of the starting chalcone epoxides.

A comparative study of organic electron transfer redox mediators: electron transfer kinetics for triarylimidazole and triarylamine mediators in the oxidation of 4-methoxybenzyl alcohol

Co-reporter:Nan-ning Lu, Seung Joon Yoo, Long-Ji Li, Cheng-Chu Zeng, R. Daniel Little

Electrochimica Acta 2014 Volume 142() pp:254-260

Publication Date(Web):1 October 2014

DOI:10.1016/j.electacta.2014.07.105

The triarylimidazoles (TAIs) constitute a promising class of organic electron transfer redox mediators that have been used to achieve indirect electrochemical C-H bonds activation and functionalization. Herein we report the diffusion and electron transfer rates for the oxidation of 4-methoxybenzyl alcohol using TAI and compare its electrochemical behavior with that of tris(4-bromophenyl)amine (TBPA). The results contribute to our understanding of the electron transfer process of electrocatalytic oxidation using TAIs, and offer useful guidelines for their further development and use.

Electrochemical synthesis of 3,5-disubstituted isoxazoles

Co-reporter:Huan-Lan Xiao, Cheng-Chu Zeng, Hong-Yu Tian, Li-Ming Hu, R. Daniel Little

Journal of Electroanalytical Chemistry 2014 Volume 727() pp:120-124

Publication Date(Web):1 August 2014

DOI:10.1016/j.jelechem.2014.06.008

The electrochemical oxidation of chalcone oximes has been explored using preparative scale electrolysis and cyclic voltammetry (CV). The results show that a constant current electrolysis of chalcone oximes in an undivided cell affords the corresponding isoxazoles in moderate to good yields, using graphite as the working electrode and NaClO4/CH3OH as the supporting electrolyte. The cyclic voltammograms for nearly all of the chalcone oximes investigated exhibit only one oxidation peak. On the basis of preparative electrolysis results and CV analysis, a reaction mechanism, involving a combination of electrochemically-generated base and an iminoxy radical intermediate, is proposed.Graphical abstract

Electrochemically Initiated Oxidative Amination of Benzoxazoles Using Tetraalkylammonium Halides As Redox Catalysts

Co-reporter:Wei-Jing Gao, Wei-Cui Li, Cheng-Chu Zeng, Hong-Yu Tian, Li-Ming Hu, and R. Daniel Little

The Journal of Organic Chemistry 2014 Volume 79(Issue 20) pp:9613-9618

Publication Date(Web):September 25, 2014

DOI:10.1021/jo501736w

An electrochemically promoted coupling of benzoxazoles and amines has been developed, leading directly to the formation of 2-aminobenzoxazoles. The chemistry utilizes catalytic quantities of a tetraalkylammonium halide redox catalyst and is carried out under constant current conditions in a simple undivided cell. The use of excess chemical oxidant or large amounts of supporting electrolyte is avoided. This greatly simplifies the workup and isolation process and leads to a reduction in waste.

Efficient Indirect Electrochemical Synthesis of 2-Substituted Benzoxazoles using Sodium Iodide as Mediator

Co-reporter:Wei-Cui Li;Li-Ming Hu;Hong-Yu Tian;R. Daniel Little

Advanced Synthesis & Catalysis 2013 Volume 355( Issue 14-15) pp:2884-2890

Publication Date(Web):

DOI:10.1002/adsc.201300502

Electrochemically induced CH functionalization using bromide ion/2,2,6,6-tetramethylpiperidinyl-N-oxyl dual redox catalysts in a two-phase electrolytic system

Co-reporter:Chao Li, Cheng-Chu Zeng, Li-Ming Hu, Feng-Lin Yang, Seung Joon Yoo, R. Daniel Little

Electrochimica Acta 2013 Volume 114() pp:560-566

Publication Date(Web):30 December 2013

DOI:10.1016/j.electacta.2013.10.093

•Electrocatalytic CH bond functionalization of tetrahydroisoquinolines is reported.•The transformation is mediated by a bromide ion/TEMPO dual redox catalyst system.•The transformation is conducted in a two-phase electrolytic medium.•The mechanism is proposed to proceed via a sequence of oxidation and addition reactions involving water as a nucleophile.•The procedure features wide substrate scope, the use of mild reaction conditions.The electrochemical oxidative functionalization of benzylic CH bonds, mediated by a dual bromide ion/2,2,6,6-tetramethylpiperidinyl-N-oxyl (TEMPO) redox catalyst system in a two-phase electrolytic medium, has been explored using cyclic voltammetry (CV) and preparative electrolysis techniques. The results show that electron transfer between TEMPO+ and a neutral substrate occurs with an efficiency that depends upon the presence of a base. The preparative scale electrolysis led to the formation of dihydro-isoquinolinones, isochromanone and xanthenone in moderate to excellent yields. On the basis of the CV analysis and preparative electrolysis results, a reaction mechanism is proposed.

Triarylimidazole Redox Catalysts: Electrochemical Analysis and Empirical Correlations

Co-reporter:Ni-tao Zhang, Cheng-chu Zeng, Chiu Marco Lam, Randi K. Gbur, and R. Daniel Little

The Journal of Organic Chemistry 2013 Volume 78(Issue 5) pp:2104-2110

Publication Date(Web):November 27, 2012

DOI:10.1021/jo302309m

A series of triarylimidazoles was synthesized and characterized electrochemically. The synthetic route is general, providing a pathway to 30 redox mediators that exhibit a > 700 mV range of accessible potentials. Most of the triarylimidazoles display three oxidation peaks where the first redox couple is quasi-reversible. The electronic character of the substituents affects the oxidation potential. This is exemplified by a linear correlation between the first oxidation potential and the sum of the Hammett σ+ substituent constants, as well as with a series of calculated ionization potentials. We close by putting forward a rule of thumb stating that for a given mediator, the upper limit of accessible potentials can be extended by at least 500 mV beyond the largest recorded value. A rationale, the conditions under which the rule is likely to apply, and an example are provided.

Electrochemical oxidation of aminophenols in the presence of benzenesulfinate

Co-reporter:Huan-Lan Xiao, Cheng-Wen Yang, Ni-Tao Zhang, Cheng-Chu Zeng, Li-Ming Hu, Hong-Yu Tian, R. Daniel Little

Tetrahedron 2013 69(2) pp: 658-663

Publication Date(Web):

DOI:10.1016/j.tet.2012.11.005

Electrochemical oxidation of catechols in the presence of enaminone: exclusive α- arylation

Co-reporter:Ni-Tao Zhang, Xiao-Guang Gao, Cheng-Chu Zeng, Li-Ming Hu, Hong-Yu Tian and Yuan-Bin She

RSC Advances 2012 vol. 2(Issue 1) pp:298-306

Publication Date(Web):04 Nov 2011

DOI:10.1039/C1RA00683E

Anodic oxidation of catechols in the presence of enaminones serving as potential doubly nucleophiles is examined using cyclic voltammetry and preparative electrolysis methods. Selective α-arylation is observed, which is consistent with that from the chemical oxidation approach. The results demonstrate that formation of either indoles or α-arylated products is depended on the nature of the polarized enaminone.

One-pot sequential combination of multi-component and multi-catalyst: synthesis of 5-aminobenzofurans from aminophenol and ketene acetals

Co-reporter:Cheng-Wen Yang, Yue-Xia Bai, Ni-Tao Zhang, Cheng-Chu Zeng, Li-Ming Hu, Hong-Yu Tian

Tetrahedron 2012 68(49) pp: 10201-10208

Publication Date(Web):

DOI:10.1016/j.tet.2012.09.090

Electrochemically induced cascade Knoevenagel–Michael reactions of tetronic acid and aldehydes: synthesis of methylenebistetronic acids

Co-reporter:Zheng-Zheng Zhang, Ni-Tao Zhang, Li-Ming Hu, Zhong-Qing Wei, Cheng-Chu Zeng, Ru-Gang Zhong and Yuan-Bin She

RSC Advances 2011 vol. 1(Issue 7) pp:1383-1388

Publication Date(Web):06 Oct 2011

DOI:10.1039/C1RA00428J

The results of cascade Knoevenagel–Michael reactions of tetronic acid and various aldehydes induced by electrochemically-generated base are described. It has been observed that electrochemical method at 0 °C gave higher yields of the corresponding methylenebistetronic acids. Also, a wide spectra of products could generate from electrolysis at room temperature, including seven-membered cyclic acetals, dehydrodimer of tetronic acid and the desired methylenebistetronic acids. The electrochemical results were also evaluated and compared with those obtained by using a conventional chemical method.

Electrochemical oxidation of catechols in the presence of ketene N,O-acetals: indole formation versus α-arylation

Co-reporter:Yue-Xia Bai, Da-Wei Ping, R. Daniel Little, Hong-Yu Tian, Li-Ming Hu, Cheng-Chu Zeng

Tetrahedron 2011 67(48) pp: 9334-9341

Publication Date(Web):

DOI:10.1016/j.tet.2011.09.126

Anodic oxidation of catechols in the presence of α-oxoketene N,N-acetals with a tetrahydropyrimidine ring: selective α-arylation reaction

Co-reporter:Cheng-Chu Zeng, Da-Wei Ping, Li-Ming Hu, Xiu-Qing Song and Ru-Gang Zhong

Organic & Biomolecular Chemistry 2010 vol. 8(Issue 10) pp:2465-2472

Publication Date(Web):24 Mar 2010

DOI:10.1039/C001847C

The electrochemical oxidation of catechols leads to the formation of o-benzoquinones. This property has been applied to effectively synthesize α-arylated products of α-oxoketene N,N-acetals with a tetrahydropyrimidine ring.

Electrochemical oxidation of substituted catechols in the presence of pyrazol-5-ones: characterization of products and reaction mechanism

Co-reporter:Xiao-Guang Gao, Cheng-Wen Yang, Zheng-Zheng Zhang, Cheng-Chu Zeng, Xiu-Qing Song, Li-Ming Hu, Ru-Gang Zhong, Yuan-Bin She

Tetrahedron 2010 66(52) pp: 9880-9887

Publication Date(Web):

DOI:10.1016/j.tet.2010.10.060

A Facile Synthesis of -Aryl -Oxoheterocyclic Ketene N,N-Acetals Bearing an Electron-Rich Catechol SubunitAn Electrochemical Oxidative Approach

Co-reporter:Cheng-Chu Zeng;Da-Wei Ping;Yi-Sheng Xu;Li-Ming Hu;Ru-Gang Zhong

European Journal of Organic Chemistry 2009 Volume 2009( Issue 33) pp:5832-5840

Publication Date(Web):

DOI:10.1002/ejoc.200900733

Abstract

Heterocyclic ketene N,N-acetals are versatile building blocks for the synthesis of nitrogen-containing heterocyclic compounds. In the present work, the anodic oxidation of catechols 2a–f in the presence of α-oxoheterocyclic ketene N,N-acetals 1a–d has been investigated using cyclic voltammetry and controlled-potential electrolysis methods. These results indicate that α-oxoheterocyclic ketene N,N-acetals could undergo Michael addition to the anodically generated o-benzoquinones and produce α-carbon-arylated products in good yields. This approach provides effective and “green“ access to the synthesis of α-aryl α-oxoheterocyclic ketene N,N-acetals containing an electron-rich aromatic ring. In addition, density functional theory calculations were performed to explain the exclusive formation of α-carbon-arylated products. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Electrochemical oxidation of catechols in the presence of 4-amino-3-methyl-5-mercapto-1,2,4-triazole bearing two nucleophilic groups

Co-reporter:Cheng-Chu Zeng, Fu-Jian Liu, Da-Wei Ping, Yuan-Li Cai, Ru-Gang Zhong, James Y. Becker

Journal of Electroanalytical Chemistry 2009 Volume 625(Issue 2) pp:131-137

Publication Date(Web):15 January 2009

DOI:10.1016/j.jelechem.2008.10.019

Electrochemical synthesis of o-benzoquinone derivatives and their in situ transformation are one of the versatile approaches for the synthesis of derivatized catechols. In the present work, electrochemical oxidation of catechols 1a–1d in the presence of a unique nucleophile, 4-amino-3-methyl-5-mercapto-1,2,4-triazole 3, bearing two nucleophilic groups (–NH2 and –SH), have been studied in phosphate buffer solutions using cyclic voltammetry and controlled-potential electrolysis (CPE) methods. The results show that only the mercapto group participated selectively in the Michael addition reaction and led to the formation of catechol substituted products of types 4 and 5, bearing a free amino group, potentially useful for further chemical modifications, e.g. of interest in biomedical applications. Various electrolytic conditions, such as the nature of anode material, amount of passed charge, pH of the electrolytic solution and cell configuration (divided or undivided cell), were also investigated to optimize the yields of corresponding products.

Design, Synthesis and Anti-HIV Integrase Evaluation of 1,2,3- Triazol-4-yl-substituted 1,4-Dihydro-4-oxo-1,5-napthyridine- 3-carboxylic Acids

Co-reporter:Jia ZENG;Xiuhua LÜ;Chengchu ZENG;Liming HU ;Rugang ZHONG

Chinese Journal of Chemistry 2009 Volume 27( Issue 5) pp:953-962

Publication Date(Web):

DOI:10.1002/cjoc.200990162

Abstract

Copper(I)-catalyzed terminal alkyne-azide 1,3-cycloaddition reaction has emerged as one of the main strategies for the rapid creation and screening of a small molecular library. The present work describes the design and synthesis of a series of 1,2,3-triazol-4-yl-substituted 1,4-dihydro-4-oxo-1,5-napthyridine-3-carboxylic acids in which the hydrophobic and hydrophilic domains were efficiently incorporated by a click reaction. The structures of the desired products 8 and 12 were characterized by spectroscopic methods and their HIV integrase inhibitory activities were also screened.

Electrochemical synthesis of 1,3,4-thiadiazol-2-ylthio-substituted catechols in aqueous medium

Co-reporter:Cheng-Chu Zeng, Fu-Jian Liu, Da-Wei Ping, Li-Ming Hu, Yuan-Li Cai, Ru-Gang Zhong

Tetrahedron 2009 65(23) pp: 4505-4512

Publication Date(Web):

DOI:10.1016/j.tet.2009.03.101

One-Pot Electrochemical Synthesis of Fused Indole Derivatives Containing Active Hydroxyl Groups in Aqueous Medium

Co-reporter:Cheng-Chu Zeng, Fu-Jian Liu, Da-Wei Ping, Li-Ming Hu, Yuan-Li Cai and Ru-Gang Zhong

The Journal of Organic Chemistry 2009 Volume 74(Issue 16) pp:6386-6389

Publication Date(Web):July 6, 2009

DOI:10.1021/jo901091s

An novel and convenient electrochemical approach was developed for the synthesis of indole derivatives from catechols and α-oxoheterocyclic ketene N,O-acetals. This method provides an environmentally benign access to fused indole derivatives containing active hydroxyls and carbonyl under mild reaction conditions.

Electrochemical synthesis of polyhydroxylated aromatic derivatives substituted with mono- and dipyrimidinyl thioethers in aqueous medium

Co-reporter:Cheng-Chu Zeng, Da-Wei Ping, Si-Cheng Zhang, Ru-Gang Zhong, J.Y. Becker

Journal of Electroanalytical Chemistry 2008 Volume 622(Issue 1) pp:90-96

Publication Date(Web):1 October 2008

DOI:10.1016/j.jelechem.2008.05.009

Polyhydroxylated aromatic pyrimidinyl thioethers are important compounds due to their potential anti-HIV integrase activity. The present work describes an electrochemical synthetic strategy and environmentally benign approach for the synthesis of these compounds, superior to conventional chemical reactions. Thus, the electrochemical oxidation of 4-substituted catechols and caffeic acid, in the presence of 2-mercaptopyrimidine derivatives 2, generates monopyrimidinylthio-substituted polyhydroxylated aromatics 3a–f in moderate yields. In the case of catechol itself and 3-substituted catechols, both mono- (3g–l) and dipyrimidinylthio-substituted derivatives (4g–l) were produced. Apparently, the anodic oxidation of catechol derivatives leads to nucleophilic addition products of types 3 and 4, which are different from the traditional nucleophilic substitution reaction of aryl halides and thiols. The electrochemically induced reaction mechanism is also discussed.

Electrochemical Synthesis of 5-Purin-6'-ylthiocatechols in Aqueous Medium

Co-reporter:Fu-Jian LIU;Da-Wei PING;Yuan-Li CAI;Ru-Gang ZHONG

Chinese Journal of Chemistry 2008 Volume 26( Issue 9) pp:1651-1655

Publication Date(Web):

DOI:10.1002/cjoc.200890298

Abstract

The electrochemical synthesis of 5-purin-6′-ylthiocatechols was carried out by anodic oxidation of catechol derivatives 1a–1d in the presence of 6-mercaptopurine (2) in aqueous solution. Results of cyclic voltammetry and controlled-potential electrolysis indicated that the starting catechols were first oxidized to the corresponding o-benzoquinone, which underwent further Michael addition with 6-mercaptopurine to produce titled products 3a–3d following an EC (E=electrochemical and C=chemical step) mechanism. Such work further demonstrates the versatility of the anodic oxidation of catechols and their in-situ transformation for the synthesis of derivatized catechols.

Electrochemical synthesis of 6-arylsulfonyl caffeic acid derivatives in aqueous medium

Co-reporter:Cheng-Chu Zeng, Cheng-Fu Liu, Jia Zeng, Ru-Gang Zhong

Journal of Electroanalytical Chemistry 2007 Volume 608(Issue 2) pp:85-90

Publication Date(Web):1 October 2007

DOI:10.1016/j.jelechem.2007.02.005

The anodic oxidation of caffeic acid in the presence of sodium benzenesulfinate in aqueous solution was studied by cyclic voltammetry and controlled potential coulometry. The results showed that similar to other simple catechol derivatives where the substituents attached directly to the benzene ring, caffeic acid was oxidized to the corresponding o-benzoquinone which underwent further Michael-addition with sodium benzenesulfinate or sodium p-methyl benzenesulfinate to produce 6-arylsulfonyl caffeic acid derivative 7a or 7b.

Design and Synthesis of p/m-[p-(un)Substituted Phenylsulfonamido]phenyl β-Diketo Acids and Quinoxalone Derivatives

Co-reporter:Cheng-Chu Zeng;Xue-Mei Li;Hong Yan;Ru-Gang Zhong

Chinese Journal of Chemistry 2007 Volume 25(Issue 8) pp:

Publication Date(Web):15 AUG 2007

DOI:10.1002/cjoc.200790219

Diketo acid derivatives are potent and selective HIV-1 integrase inhibitors. To investigate the detailed synthesis of those derivatives, a series of p/m-[p-(un)substituted phenylsulfonamido]phenyl β-diketo acid derivatives have been designed and synthesized. The quinoxalone derivatives as the potential bioisosteres of the biologically labile β-diketoacid pharmacophores have also been synthesized from reactions of the corresponding diketo acids with o-phenylenediamine. The structures of all diketo acid (ester) and quinoxalone derivatives were confirmed by ¹H NMR, ¹³C NMR, IR, HRMS and/or MS (ESI). X-ray crystallographic analysis of 11b demonstrates a similar arrangement of the side chain of quinoxalone derivatives with the parent diketoacids due to the intramolecular hydrogen bond (O···H–N) and the sp² hybridization configuration of the two nitrogen atoms of the quinoxalone ring.

Design, Synthesis and Cu2+ Recognition of β-Diketoacid and Quinoxalone Derivatives Bearing Caffeoyl or Galloyl Moieties Linked by Arylamide as Potential HIV Integrase Inhibitors

Co-reporter:Yi-Sheng Xu;Xue-Mei Li;Ru-Gang Zhong;Yi Zeng

Chinese Journal of Chemistry 2006 Volume 24(Issue 8) pp:

Publication Date(Web):9 AUG 2006

DOI:10.1002/cjoc.200690203

An efficient procedure for the synthesis of caffeoyl- and galloyl-containing β-diketoacid derivatives linked by arylamide was reported by, in the key step, dissolving the corresponding phenyl methyl ketone in THF/DME in the presence of NaOMe as base and dimethyl oxalate as oxalylation reagent, and then separating the sodium ketoenolate ester. The resulting β-diketoacids underwent further condensation reaction with o-phenylenediamine to generate quinoxalone derivatives in good yield, rather than 2-benzimidazol. The preliminary ion binding properties of quinoxalone derivatives were also investigated. UV-Vis spectra showed that these compounds could selectively recognize Cu²⁺ ion in ethanol and form a 1:2 complex.

Electrochemical regioselective azidoiodination of alkenes

Co-reporter:Wei-qing Yan, Meng-ying Lin, R. Daniel Little, Cheng-Chu Zeng

Tetrahedron (9 February 2017) Volume 73(Issue 6) pp:764-770

Publication Date(Web):9 February 2017

DOI:10.1016/j.tet.2016.12.058

Novel Triarylimidazole Redox Catalysts: Synthesis, Electrochemical Properties, and Applicability to Electrooxidative C–H Activation

Co-reporter:Cheng-chu Zeng ; Ni-tao Zhang ; Chiu Marco Lam ;R. Daniel Little

Organic Letters () pp:

Publication Date(Web):February 16, 2012

DOI:10.1021/ol300195c

A new class of metal-free, easy to synthesize redox catalysts based on a triarylimidazole framework is described. With those synthesized thus far, one can access a potential range of ca. 410 mV. They proved to be useful mediators for the activation of benzylic C–H bonds under mild conditions.

Anodic oxidation of catechols in the presence of α-oxoketene N,N-acetals with a tetrahydropyrimidine ring: selective α-arylation reaction

Co-reporter:Cheng-Chu Zeng, Da-Wei Ping, Li-Ming Hu, Xiu-Qing Song and Ru-Gang Zhong

Organic & Biomolecular Chemistry 2010 - vol. 8(Issue 10) pp:NaN2472-2472

Publication Date(Web):2010/03/24

DOI:10.1039/C001847C