Article
Chemistry, Physical
Jiamin Huang, Feixiang Sun, Weiping Liu
Summary: In this study, the deoxygenation of secondary and tertiary amides using [Mn(CO)5Br] with Ph2SiH2 or inexpensive PMHS as reducing agents was reported, providing a convenient method for the synthesis of corresponding secondary and tertiary amines. The transformation is operationally simple, proceeds under mild conditions without external ligands, and exhibits high catalytic efficacy and good functional-group tolerance. Furthermore, the generality of this catalytic system was demonstrated by the late-stage modification of bioactive molecules.
JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Jian Huang, Han-Han Kong, Si-Jia Li, Rui-Jin Zhang, Hao-Dong Qian, Dan-Ran Li, Jin-Yu He, Yi-Nuo Zheng, Hao Xu
Summary: The highly enantioselective copper-catalyzed propargylic amination of propargylic esters with amine hydrochloride salts using chiral N,N,P-ligands has been successfully developed. This method demonstrates a broad substrate scope and wide functional group tolerance, producing propargylic amines in good to excellent yields with high enantioselectivities (up to 99% ee). The approach was further validated by late-stage functionalization of marketed pharmaceuticals.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Inorganic & Nuclear
Milan Kumar Bisai, Kritika Gour, Tamal Das, Kumar Vanka, Sakya S. Sen
Summary: A selective and efficient method for the deoxygenative reduction of primary to tertiary amides to corresponding amines using pinacolborane (HBpin) and 2,6-di-tert-butyl phenolate lithium center dot THF (1a) as a catalyst has been achieved. Both experimental and DFT studies provide mechanistic insight into the process.
DALTON TRANSACTIONS
(2021)
Article
Chemistry, Organic
Vinothkumar Vinayagam, Subir Kumar Sadhukhan, Satish Kumar Karre, Ravuri Srinath, Ravi Kumar Maroju, Purushotham Reddy Karra, Hema Sundar Naveen Babu Bathula, Siva Kundrapu, Srikanth Reddy Surukonti
Summary: A simple, mild, and metal-free catalytic protocol using stable tetrabutylammonium difluorotriphenylsilicate and silanes is developed for converting amides to amines. The protocol offers operational simplicity, safety, short reaction times, room temperature reaction, broad substrate scope, and scalability.
Article
Chemistry, Inorganic & Nuclear
Nadia Ismaeel, Zhixing Zhuo, Sajid Imran, Dan Yuan, Yingming Yao
Summary: Rare earth/lithium complexes stabilized by ethylenediamine-bridged bis(phenolate) ligands have been synthesized and characterized. Among them, the yttrium/lithium complex showed high catalytic activity for the amidation of primary aliphatic amines.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Organic
Yuvraj A. Kolekar, Bhalchandra M. Bhanage
Summary: An efficient method for synthesizing tertiary amides from aryl boronic acids and inert tertiary amines via oxidative carbonylation was presented, with significantly reduced homocoupling biarylketone formation. The use of homogeneous PdCl2/CuI and heterogeneous Pd/C catalysts promotes C(sp(3))-N bond activation between tertiary amines and aryl boronic acids, utilizing a ligand-free, base-free, and recyclable catalyst system with molecular oxygen as an ideal oxidant.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Xiao-kang Nie, Yue Chen, Shi-qi Zhang, Xin Cui, Zhuo Tang, Guang-xun Li
Summary: We have developed a catalytic asymmetric tandem reaction for the synthesis of chiral alpha-amino ketones, by mimicking the catalytic mechanism of glucosamine-6-phosphate synthase in organisms.
Article
Chemistry, Multidisciplinary
Medina Afandiyeva, Xijue Wu, William W. Brennessel, Abhishek A. Kadam, C. Rose Kennedy
Summary: This paper describes a novel nickel catalyst and its effective application in the hydroboration of nitriles. By using a tethered NHC-pyridonate ligand, both reagents can be activated simultaneously, enabling efficient catalysis at room temperature.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Organic
Hui-cheng Cheng, Lichao Zhou, Xuming Zhou, Jiao-li Ma, Penghu Guo, Yang Zhang, Hong-bing Ji
Summary: An efficient methodology for synthesizing N-arylamides via copper-catalyzed amidation of diaryliodonium salts with nitriles has been developed, yielding a series of N-arylated amides in moderate to good yields. This provides an alternative route for the synthesis of various N-arylamides, with a proposed mechanism based on control experiments presented.
TETRAHEDRON LETTERS
(2021)
Article
Chemistry, Organic
Cong Lv, Ruisheng Zhao, Xiuying Wang, Dan Liu, Tegshi Muschin, Zhaorigetu Sun, Chaolumen Bai, Agula Bao, Yong-Sheng Bao
Summary: Here, we demonstrate the simultaneous activation of alpha-C-H and C-N bonds in unactivated secondary amides by a copper catalyst to synthesize alpha-ketoamides or alpha-ketoesters in one step. This challenging and underdeveloped transformation is achieved using copper as a catalyst and air as an oxidant, and is compatible with a wide range of acetoamides, amines, and alcohols. The mechanism studies suggest that the reaction involves radical alpha-oxygenation followed by transamidation, with the assistance of N,O-chelation and molecular oxygen as an initiator.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Jessica M. L. Elwood, Martyr C. Henry, J. Daniel Lopez-Fernandez, Jenna M. Mowat, Mhairi Boyle, Benjamin Buist, Keith Livingstone, Craig Jamieson
Summary: We have reported the use of N-2,4-dinitrophenyltetrazoles as latent active esters (LAEs) in the synthesis of amide bonds. This method allows the generation of an HOBt-type active ester without the need for exogenous coupling agents. The methodology is applicable to a wide range of substrates, providing quantitative yields. The versatility and functional group tolerance were demonstrated in the one-step synthesis of various pharmaceutical agents and the N-acylation of resin-bound peptides.
Article
Chemistry, Multidisciplinary
Ashmita Singh, A. K. Narula
Summary: A facile method for the amidation of aldehydes by a cascade approach has been developed using NHC as the catalyst and NHS as the mediator. The method utilizes TBHP as the oxidant. Various substituted aldehydes reacted smoothly with NHS to form active esters, which were easily converted into amides. The drug moclobemide was successfully synthesized using this methodology to demonstrate its practical utility.
NEW JOURNAL OF CHEMISTRY
(2021)
Article
Chemistry, Organic
Hao Song, Yao Xiao, Zhuohua Zhang, Wanjin Xiong, Ren Wang, Liangcheng Guo, Taigang Zhou
Summary: A new synthetic method for the selective transfer hydrogenation of nitriles to primary amine-boranes and secondary amines has been developed. The method demonstrates high selectivity and yields up to 95%, and has been successfully applied in the synthesis of N-15 labeled compounds with an 89% yield.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Applied
Natalia S. Soldatova, Artem V. Semenov, Kirill K. Geyl, Sergey V. Baykov, Anton A. Shetnev, Anna S. Konstantinova, Mikhail M. Korsakov, Mekhman S. Yusubov, Pavel S. Postnikov
Summary: A method for copper-catalyzed N-arylation of diverse oxadiazolones using diaryliodonium salts has been reported with high yields up to 92%. It was found that the steric effects in aryl moieties determined the chemoselectivity of arylations. Mesityl-substituted diaryliodonium salts demonstrated high potential as selective arylation reagents.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Organic
Sayan Shee, Deeptanu Sarkar, Akkattu T. Biju
Summary: The enantioselective synthesis of functionalized pyrazoloquinolin-3-ones via N-heterocyclic carbene-catalyzed cascade reaction of alpha-bromoenals with 2-aminoaryl N-tosyl hydrazones is described. The in situ-generated alpha,beta-unsaturated acylazoliums undergo an aza-Michael-Mannich-lactamization sequence to afford tricyclic products with three contiguous stereocenters, including a sterically demanding quaternary stereocenter with high enantioselectivity. The preference for the unprotected amine-triggered aza-Michael pathway over the competing amidation pathway is notable.
Article
Chemistry, Organic
Krishnadipti Singha, Subhash Chandra Ghosh, Asit Baran Panda
Summary: Amides were efficiently synthesized from alcohols and amines at high yields using an in situ generated active ester of N-hydroxyimide with a Cu-N-TiO2 catalyst. The catalyst is easily prepared, robust, and can be recycled multiple times without significant loss of catalytic activity.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Aymeric Cervi, Yen Vo, Christina L. L. Chai, Martin G. Banwell, Ping Lan, Anthony C. Willis
Summary: Efficient methods for the synthesis of phenol-derived propiolates and their Au(I)-catalyzed cyclization to give coumarins have been reported. These methods have been successfully applied to the synthesis of natural products such as ayapin and scoparone.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Harshvardhan Singh, Chiranjit Sen, Eringathodi Suresh, Asit B. Panda, Subhash C. Ghosh
Summary: This atom-economical and efficient route for the direct amidation and amination of aryl C-H bonds using the synthesized recyclable heterogeneous Cu-MnO catalyst shows excellent results with good to excellent yields under mild conditions; the catalyst can be reused several times without significant loss of reactivity, demonstrating its environmental friendliness and cost-effectiveness.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Polymer Science
Ping Sen Choong, Ning Xi Chong, Eric Kwok Wai Tam, Abdul Majeed Seayad, Jayasree Seayad, Satyasankar Jana
Summary: This article presents the development of bio-/CO2-derived nonisocyanate polyurethane (NIPU) coatings, which have high levels of renewable carbon and self-healing properties through three different healing mechanisms: thermo-healing, moisture-healing, and self-healing at room temperature. The coatings feature a unique combination of recyclability and intrinsic healing capabilities, making them ideal for sustainable and functional applications.
Article
Chemistry, Multidisciplinary
Mohammadreza Kosari, Uzma Anjum, Shibo Xi, Alvin M. H. Lim, Abdul Majeed Seayad, Emmanuel A. J. Raj, Sergey M. Kozlov, Armando Borgna, Hua Chun Zeng
Summary: This study explores the impact of a novel maze-like nanoreactor framework (MVmSiO(2)) on CO2 hydrogenation, demonstrating enhanced CO2 activity, improved methanol yield, and prolonged stability. Beyond morphology optimization, the architectural design of the support also plays a significant role in improving reaction performance.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Nathanael Hsueh, Christina L. L. Chai
Summary: This study focused on the design and synthesis of catechol-derived ATRP initiators containing the 2-bromoisobutyryl moiety, and investigated the impact of structural changes on initiator immobilization and subsequent ATRP performance. The results showed that changes in the length of the linker unit bearing the 2-bromoisobutyryl moiety, the introduction of a free amine group, or the replacement of the amide with an ester had profound effects on the ability of the molecule to deposit ATRP-initiator-modified PDA coatings, as well as the subsequent SI-ATRP performance.
Review
Chemistry, Medicinal
Malcolm Z. Y. Choo, Christina L. L. Chai
Summary: Many concepts and guidelines in medicinal chemistry can aid in successful drug discovery and development, but rigid and blind use of them may hinder productivity. Therefore, attention should be given to limitations in assays to increase the chances of successful drug discovery.
Article
Chemistry, Medicinal
Quy Thi Ngoc Tran, Regina Ching Hua Lee, Hon Jin Liu, Danli Ran, Vincent Zhan Lin Low, Dong Quang To, Justin Jang Hann Chu, Christina Li Lin Chai
Summary: This study reports a new class of small-molecule CHIKV inhibitors, oxindole-labdanes, which can effectively block the replication of CHIKV with good selectivity. Compound (E)-42 shows high antiviral activity and minimal cytotoxicity to host cells, demonstrating both prophylactic and therapeutic effects. This finding opens up a new avenue for the development of antiviral drugs against CHIKV infection.
EUROPEAN JOURNAL OF MEDICINAL CHEMISTRY
(2022)
Article
Pharmacology & Pharmacy
Wupeng Liao, Hazel Yu Ci Foo, Thi Ngoc Quy Tran, Christina Li Lin Chai, Wai Shiu Fred Wong
Summary: This study evaluated the protective effects of CalD in a house dust mite (HDM)-induced asthma mouse model. CalD reduced various inflammatory markers and improved lung function in the mice. It modulated the function of alveolar macrophages and had potential as a novel anti-inflammatory compound for allergic asthma.
BRITISH JOURNAL OF PHARMACOLOGY
(2023)
Article
Chemistry, Organic
Dinesh Gopichand Thakur, Tapan Sahoo, Chiranjit Sen, Nilesh Rathod, Subhash Chandra Ghosh
Summary: We have developed a new method for the synthesis of aryl quinolinyl ketones using Pd-catalyzed direct C-H arylation of quinoline-8-carbaldehydes with either aryl iodides or aryl diazonium salts. Aryl iodides substituted with an electron-donating group showed favorable reactivity, while aryl diazonium salts substituted with an electron-withdrawing group exhibited excellent reactivity. A range of aryl quinolinyl ketones were synthesized in good-to-excellent yields, with excellent functional group tolerance. Additionally, our methodology was successfully applied to synthesize highly potent tubulin polymerization inhibitors and can be easily scaled up to a gram scale.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Review
Chemistry, Physical
Mohammadreza Kosari, Alvin M. H. Lim, Yu Shao, Bowen Li, Kelvin M. M. Kwok, Abdul Majeed Seayad, Armando Borgna, Hua Chun Zeng
Summary: Solid siliceous materials play an important role in carbon capture and utilization (CCU) by converting CO2 into valuable chemical commodities. Siliceous catalysts are widely used for CO2 thermal conversion due to their tunable porosity, high thermal resistivity, and ease of preparation. In terms of catalytic performance, siliceous-based catalysts are comparable to non-precious and precious metal catalysts. This review focuses on recent advances in CO2 conversion using silica/silicate-based catalysts, including gas-phase reduction pathways, design and synthesis techniques, and different types of catalysts. The potential for CO2 conversion to hydrocarbons, alcohols, and specialty organic substances using siliceous-based catalysts is emphasized.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
Materials Science, Multidisciplinary
Ping Sen Choong, Kwok Wai Eric Tam, Ning Xi Chong, Abdul Majeed Seayad, Jayasree Seayad, Satyasankar Jana
Summary: This study reports a single-step synthesis method for water-soluble and bio-derived linear amine-based non-isocyanatepolyurethanes (NIPUs). These polymers exhibit good water solubility and dispersion, making them potential candidates as anti-soil/dirt redepositioning agents in home care applications. They are also noncytotoxic and non-skin irritants, demonstrating their suitability for further use. The development and utilization of such green, sustainable, and biodegradable NIPUs may replace the current toxic and nondegradable ingredients in various applications.
ACS APPLIED POLYMER MATERIALS
(2023)
Article
Chemistry, Organic
Raj N. N. Patel, Dharmik M. M. Patel, Nileshkumar B. B. Rathod, Dinesh G. G. Thakur, Sachinkumar D. D. Patel, Srinu Tothadi, Subhash Chandra Ghosh
Summary: A cobalt-catalyzed, N,O-bidentate directing group-assisted C-H bond functionalization of benzamides with maleimides was developed for the facile access to isoindolone spirosuccinimides in good to excellent yields. This C-H bond activation and spirocyclization employing pyridine N-oxide as directing group provided very good substrate scope and tolerated various functional groups. Furthermore, the mechanistic investigation revealed that the C-H bond activation is the rate-determining step of this reaction.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Souvik Sarkar, Tapan Sahoo, Chiranjit Sen, Subhash Chandra Ghosh
Summary: The synthesis of hindered alkyl aryl ether derivatives remains a significant challenge and desirable goal in organic and medicinal chemistry. This study reports a successful method for the synthesis of highly desirable alpha-tertiary alkyl aryl ethers through hindered alkoxylation of specific substrates.
CHEMICAL COMMUNICATIONS
(2021)
Review
Biochemistry & Molecular Biology
Quy T. N. Tran, W. S. Daniel Tan, W. S. Fred Wong, Christina L. L. Chai
Summary: Andrographolide, a widely studied plant secondary metabolite, has diverse pharmacological targets associated with prevalent diseases. Despite documented efficacy in disease models, challenges such as multi-targeting properties and discrepancies in bioavailability have hindered its development as a therapeutic agent.
NATURAL PRODUCT REPORTS
(2021)