Article
Chemistry, Multidisciplinary
Hai Huang, Tianyu Zhang, Jianwei Sun
Summary: The use of soft carbon nucleophiles to open oxetanes has been developed for efficient C-C bond formation. Silyl ketene acetals and styrene-based carbon nucleophiles can generate a wide range of highly oxygenated molecules in the presence of catalysts, which are key substructures in natural products.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Tianyu Zhang, Han Zhuang, Luning Tang, Zhengyu Han, Wengang Guo, Hai Huang, Jianwei Sun
Summary: A novel intramolecular C-C formation process based on catalytic asymmetric oxetane opening by carbon nucleophiles has been developed, allowing for the rapid synthesis of valuable enantioenriched 2,3-dihydrobenzo[b]oxepines under mild conditions with good chemical efficiency and enantioselectivity. The products also serve as useful precursors to other valuable structures.
Article
Chemistry, Applied
Cristina Maquilon, Francesco Della Monica, Bart Limburg, Arjan W. Kleij
Summary: An operationally mild, ruthenium-based photocatalytic protocol has been developed for the conversion of gamma-mono- and gamma,gamma-disubstituted allyl carbonates to substituted six-membered cyclic carbonates. The variation and diversification of carbonate ring substitution provides access to new monomers useful in ring-opening polymerization, leading to polycarbonates with potentially tailored properties.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Organic
Shuo Wang, Atsushi Kaga, Takashi Kurogi, Hideki Yorimitsu
Summary: In this study, treatment of arylcyclopropanecarboxamides with a sodium dispersion in the presence of methoxypinacolborane as a reduction-resistant electrophile was investigated. The results showed that the reaction led to the reductive cleavage of the cyclopropane ring followed by instant trapping with the boron electrophile, resulting in the formation of enolates of gamma-aryl-gamma-borylalkanamides. The enolates could further react with a different electrophile to produce the corresponding a-substituted amides with anti selectivity.
Article
Chemistry, Organic
David Leparfait, Feng Xiao, Delphine Coupri, Sabrina Gueulle, Florie Desriac, Aurelie Budin-Verneuil, Nicolas Verneuil, Axel Hartke, Emmanuel Pfund, Thierry Lequeux
Summary: Tri- and tetra-substituted alkenes, including fluoroalkenes, were obtained via selective ring-opening reaction of functionalized oxetanes. By introducing adenine nucleic base, alkenyl and fluoroalkenyl derivatives were synthesized as potential nucleoside mimics and evaluated for their activity against DltA enzyme.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Polymer Science
Lanlan Zheng, Jiabing Feng, Hongyan Xie, Zhiguang Xu
Summary: In this study, the use of phosphazene base (P1) and triethyl borane (TEB) as organocatalysts has been demonstrated for the ring-opening copolymerization (ROCOP) of 3,5-anhydro-D-xylose oxetane 1 and various anhydrides. The ROCOP efficiently generates sugar-derived polyesters with perfectly alternating sequence distribution, controlled molar masses, and moderate dispersity. These polyesters exhibit good thermal stability (T-max > 320 degrees C) and adjustable glass transition temperatures (T-g 70 to 110 degrees C). This work provides an efficient organocatalyst for the selective copolymerization of biomass-derived degradable polyesters.
JOURNAL OF POLYMER SCIENCE
(2023)
Review
Chemistry, Organic
Austin Pounder, Angel Ho, Matthew Macleod, William Tam
Summary: Oxabenzonorbornadiene (OBD) is a useful synthetic intermediate that can be activated by transition metal complexes with great face selectivity due to its dual-faced nature and intrinsic angle strain. The nature of C1-substituent in unsymmetrical OBDs has a profound effect on the reactivity and selectivity of reactions, leading to the formation of multiple stereo-, regio-, and constitutional isomers. Understanding bridgehead substituent effects is crucial for maximizing selectivity in the chemistry of unsymmetrical C1-substituted OBDs.
CURRENT ORGANIC SYNTHESIS
(2021)
Article
Chemistry, Analytical
Yanju Liu, Lulu Hao, Wenbin Wang, Huaixia Yang, Fuchun Si, Jinming Kong
Summary: This study introduced a sensitivity-improved immunosensor using functionalized graphene oxide and ring-opening polymerization strategy, demonstrating high sensitivity and applicability for detecting non-small cell lung cancer-specific biomarkers. Satisfactory results in clinical serum samples suggest the enormous potential of this immunosensor in practical clinical application.
Article
Chemistry, Multidisciplinary
Jonas Hadeler, Gunasekaran Velmurugan, Rebekka Lauer, Rejith Radhamani, Frank Keppler, Peter Comba
Summary: Organic and inorganic volatile compounds with one carbon atom (C-1), such as carbon dioxide, methane, and formaldehyde, play a crucial role in global carbon cycling and atmospheric physics and chemistry. Previous studies suggested that these compounds were primarily associated with biological or combustion processes. However, new evidence suggests that many C-1 and C-2 compounds may originate from the formation of methyl radicals through iron oxide-mediated reactions. This finding has significant implications for understanding carbon cycling and atmospheric processes.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Organic
Subaramaniam Thangamalar, Kannupal Srinivasan
Summary: The ring-opening reaction of nitro-substituted donor-acceptor cyclopropanes with pyrazoles in DMSO was investigated. Unexpectedly, the cyclopropanes underwent Kornblum-type ring-opening oxidation with DMSO to form aroylmethylidene malonates as intermediates in the reactions. The intermediates further underwent aza-Michael addition with pyrazoles in tandem manner to give the corresponding aza-Michael adducts. The highlights of the methodology include the occurrence of ring-opening/oxidation under neutral conditions with DMSO and formation of aza-Michael adducts with pyrazoles under catalyst-free conditions.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Yu Meng Yang, Er Juan Zhao, Wanqing Wei, Zi Fei Xu, Jing Shi, Xuan Wu, Bo Zhang, Yasuhiro Igarashi, Rui Hua Jiao, Yong Liang, Ren Xiang Tan, Hui Ming Ge
Summary: In this study, a cytochrome P450 enzyme that can catalyze the formation of a benzene ring from an acyclic polyene substrate has been characterized. Through genome mining guided by this P450 enzyme, 12 homologous type I polyketide synthase gene clusters were obtained, among which two clusters were found to produce trialkyl-substituted aromatic polyketides. Quantum chemical calculations were performed to explore the possible mechanism for the P450-catalyzed benzene ring formation, expanding our knowledge of the catalytic diversity of cytochrome P450.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Review
Polymer Science
Pulikanti Guruprasad Reddy, Abraham J. Domb
Summary: This review discusses the recent advances in the study of polyester-based micro/nanoparticles and microspheres derived from dispersion ring-opening polymerization of heterocyclic monomers, self-assembly of polyester macromolecules, and dialysis of polyester solution. Various synthetic strategies have been developed for the formation of polyester particles with controlled diameter distribution, influenced by factors such as the structure of polymer surfactant, critical micelle concentration of surfactant, and type of radical initiator/monomer used.
POLYMERS FOR ADVANCED TECHNOLOGIES
(2021)
Article
Polymer Science
Dong-fang Zhao, Zheng Li, Yong Shen, Zhi-bo Li
Summary: This study described an efficient synthesis of two oxolactone monomers using an alcoholysis product of poly(3-hydroxybutyrate) (P3HB). The monomers were polymerized and the behavior of polymerization was investigated. The resulting polymers had controlled molecular weights and end groups. Additionally, the study achieved the depolymerization and recovery of the polymer using a catalyst, extending the material's life cycle.
ACTA POLYMERICA SINICA
(2023)
Article
Chemistry, Physical
Xianjun Xu, Liangliang Song, Huangdi Feng, Erik V. Van Der Eycken
Summary: The development of economically feasible strategies for constructing structurally diverse isoquinolones is still challenging. In this study, a practical Pd-catalyzed cyclization/base-promoted ammatization/ring-opening protocol for N-propargyl-1,3-oxazolidines with carboxylic acids was disclosed. The domino reaction resulted in a series of ester-functionalized isoquinolones in moderate to good yields through C-O bond cleavage, demonstrating a broad functional group tolerance.
MOLECULAR CATALYSIS
(2022)
Article
Chemistry, Organic
Mingzhong Wu, Chaoxian Yan, Daijiao Zhuang, Rulong Yan
Summary: A general approach for metal-free synthesis of thiophenes has been developed using tert-cyclobutanols and elemental sulfur. This method provides a strategy for constructing multisubstituted thiophene derivatives through C-S bond formation under air. The reaction shows good functionality tolerance under the reaction conditions and the mechanism has been validated through control experiments and density functional theory calculations.
Article
Chemistry, Organic
Manas Jyoti Sarma, Sana Jindani, Bishwajit Ganguly, Srihari Pabbaraja, Goverdhan Mehta
Summary: An efficient protocol for the synthesis of orthogonally strap diynones through one pot transition-metal-free reaction has been developed. Insights into the regioselective tandem Michael-anti-Michael processes have been gleaned through DFT calculations.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
P. Srihari, Y. Bharath Kumar, B. Suresh
ORGANIC PREPARATIONS AND PROCEDURES INTERNATIONAL
(2022)
Article
Chemistry, Organic
Ravi Gurram, Srihari Pabbaraja
Summary: A stereoselective synthetic strategy for (+)-paecilomycin F was developed using readily available 2,4,6-trihydroxy benzoic acid and chiral R(+)-propylene oxide. The synthesis involved key reactions such as regioselective Grignard reaction, Wittig reaction, Sharpless asymmetric dihydroxylation, Barbier-type allylation, Stille-coupling, and ring-closing metathesis. The target molecule was successfully synthesized in a 7-step linear sequence with a 20% overall yield starting from 2,4,6-trihydroxy benzoic acid, or a 12-step sequence with a 12.95% overall yield starting from R(+)-propylene oxide.
LETTERS IN ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
N. K. Chouhan, Sudarshana K. Ananthabhat, Sandeep Vaidya, P. Srihari
Summary: A highly efficient and scalable process for the synthesis of novoldiamine and hydroxynovaldiamine from levulinic acid has been achieved. These compounds are crucial intermediates for the synthesis of antimalarial drugs chloroquine, hydroxychloroquine, and mepacrine.
SYNTHETIC COMMUNICATIONS
(2022)
Article
Biochemistry & Molecular Biology
Ganesh Kumar Raut, Genji Sukumar, Moumita Chakrabarti, Jolly Janette Mendonza, Srihari Pabbaraja, B. Jagan Mohan Reddy, Ramakrishna Sistla, Sai Balaji Andugulapati, Manika Pal Bhadra
Summary: Polyphenols are natural compounds with anti-tumorigenic effects. This study designed and synthesized a compound that interferes with the cell cycle progression in aggressive prostate cancer. Further experiments showed that the compound inhibits the viability of prostate cancer cells and induces apoptosis through oxidative stress. In a mouse model, the compound showed no toxicity and reduced the tumor burden.
Review
Chemistry, Organic
Saumitra Sengupta, Srihari Pabbaraja, Goverdhan Mehta
Summary: Recursive Anionic Cyclization (RAC) is a mechanistically distinct domino strategy that continues to grow. By using nitroalkanes as a source of recursive carbanions, it has created a unique operating space for generating molecular complexity and diversity. The recursive nitronate cyclization, based on a domino [5 C+1 C] cyclization strategy, allows rapid access to densely functionalized carbo- and heterocycles with multiple chiral centers and regio-, stereo- and enantioselectivity. Extension to aromatic domains, particularly through benzannulation reactions, has further expanded the operating space. The functional versatility of nitro group has also been leveraged for post-domino modifications, leading to total synthesis of various natural products.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Srihari Pabbaraja, Bharath Kumar Yasam
Summary: A flexible stereoselective and convergent cum divergent approach to the synthesis of two 13-membered macrolides through a common skeleton is described. The synthesis is achieved using two different routes, resulting in a good overall yield. Key synthetic reactions include Keck allylation, Evans asymmetric methylation, Grubbs metathesis, and Julia-Kocienski olefination.
Article
Chemistry, Organic
Bhushan Mahajan, Dnyaneshwar Aand, Mandeep Purwa, Taufiqueahmed Mujawar, Subhash Ghosh, Srihari Pabbaraja, Ajay K. Singh
Summary: Researchers have used a nanotextured Ni@Cu material embedded electro microflow reactor to synthesize biphenyls in a fast and efficient manner, without the use of noble metals. By optimizing the reactor volume and integrating the process system, they have successfully achieved gram-scale biphenyl synthesis and continuous microflow synthesis of daclatasvir.
SYNTHESIS-STUTTGART
(2023)
Article
Chemistry, Physical
Deepak Kumar Jaiswal, Dnyaneshwar Aand, Puchakayala Krishna Rao, Sibaji Nandi, Srihari Pabbaraja, Ajay K. Singh
Summary: The deactivation of toxic gases and the separation of liquids through metal-organic frameworks (MOFs) have made significant advancements in this growing field. However, the stability of MOFs and their sensitivity to water are still being developed. In this study, a new strategy using scalable and safely generated continuous flow diazomethane is proposed to seal moisture-sensitive functionality in hydrophobic MOFs, demonstrating improved hydrophobicity and its applications in organic/aqueous phase separation and self-cleaning. This work presents the first attempt to seal sensitive functional groups with diazomethane for hydrophobic MOFs, exploring a new proof of concept for designing stable MOFs with controlled wettability. The concept of MOF diazomethane treatment can also be expanded to design and develop advanced membranes for effectively separating aqueous organic solutions, providing valuable insights.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Organic
Manas Jyoti Sarma, K. A. Sudarshana, Goverdhan Mehta, Pabbaraja Srihari
Summary: This study reveals the discovery of reaction regime controlled product diversification in a one-pot reaction between diynones and dimethyl-1,3-acetonedicarboxylate (DMAD), which selectively furnishes either functionally unique pentasubstituted o-alkynylbenzoates or fully substituted furan-3(2H)-ones. Furthermore, the potential of these two versatile platforms to enter new utilitarian chemical space has been explored.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Manas Jyoti Sarma, K. A. Sudarshana, Srihari Pabbaraja, Goverdhan Mehta
Summary: Spiroannulation of oxindole-3-oxy acrylates with ynones involving two overlapping, base differentiated cascades has been observed. The initial tandem Michael-Michael cascade delivers a pair of spiroannulated diastereomers, while a second multistep cascade involving stereoselective restructuring leads to the formation of 3H-spiro[furan-2,3'-indolin]-2'-ones with functional amplification and scrambling. This new scaffold can be synthesized in one flask from ynones and oxindole-3-oxy acrylates.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Review
Chemistry, Multidisciplinary
Saumitra Sengupta, Srihari Pabbaraja, Goverdhan Mehta
Summary: Intrusion into the C-H chemical space of natural products through C-H functionalization reactions can create new molecular diversities and impact biological functions. Semisynthetic C-H modification of natural products is becoming a minimalistic approach in drug discovery. Examples of C-H modification of natural products resulting in improved pharmacological attributes and opportunities in allied areas continue to be reported. This article highlights the evolving paradigm of natural product and synthetic chemistry research to accelerate and broaden natural product-based drug discovery.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Organic
Naresh Gantasala, Corentin Fournet, Myriam Le Roch, Claudia Lalli, Srihari Pabbaraja, Nicolas Gouault
Summary: A novel approach for constructing 2-spiropiperidine moieties was developed using dihydropyridones. The addition of allyltributylstannane onto dihydropyridones promoted by triflic anhydride resulted in the formation of gem bis-alkenyl intermediates, which were then converted to the corresponding spirocarbocycles through ring closing metathesis with high yields. The vinyl triflate group generated on these 2-spiro-dihydropyridine intermediates could be successfully utilized as a chemical expansion vector for Pd-catalyzed cross-coupling reactions.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
Article
Chemistry, Medicinal
Mani Sharma, S. S. S. S. Sudha Ambadipudi, Neeraj Kumar Chouhan, V. Lakshma Nayak, Srihari Pabbaraja, Sai Balaji Andugulapati, Ramakrishna Sistla
Summary: Therapeutically active lipids in drug delivery systems can enhance the safety and efficacy of treatment. The liposome formulation created using synthesized biologically active lipids showed additive anti-cancer effects and reduced tumorigenic potential.
BIOORGANIC & MEDICINAL CHEMISTRY LETTERS
(2024)
Article
Chemistry, Multidisciplinary
Gandhari Kishor, Vankudoth Ramesh, Vadithya Ranga Rao, Srihari Pabbaraja, Praveen Reddy Adiyala
Summary: An efficient visible-light driven continuous-flow C-3-alkylation of quinoxalin-2(1H)-ones was achieved using Katritzky salts as alkylating agents. The reaction was catalyzed by eosin-y and base DIPEA at room temperature. The protocol utilized inexpensive alkyl amines and amino acid feedstocks to synthesize a variety of C-3-alkylated quinoxalin-2(1H)-ones. The reaction was carried out in a PFA capillary microreactor under blue LED irradiation, resulting in excellent yields and shorter reaction times compared to a batch system.