Article
Chemistry, Medicinal
Diana I. S. P. Resende, Joana R. Almeida, Sandra Pereira, Alexandre Campos, Agostinho Lemos, Jeffrey E. Plowman, Ancy Thomas, Stefan Clerens, Vitor Vasconcelos, Madalena Pinto, Marta Correia-da-Silva, Emilia Sousa
Summary: This study investigated the antifouling activity of a series of xanthones against mussel larvae settlement, with compounds 21 and 23 showing the most promising results. The research demonstrated the potential of C-1 aminated xanthones with a 3,4-dioxygenated pattern of substitution as new non-toxic products to prevent marine biofouling.
Article
Chemistry, Multidisciplinary
Yi-Feng Wang, Chao-Jie Wang, Qing-Zhou Feng, Jing-Jing Zhai, Suo-Suo Qi, Ai-Guo Zhong, Ming-Ming Chu, Dan-Qian Xu
Summary: A Cu-catalyzed asymmetric 1,6-conjugate addition of in situ generated para-quinone methides (p-QMs) with beta-ketoester has been developed to construct a ketoester skeleton bearing an adjacent tertiary-quaternary carbon stereocenter in good yields and high enantioselectivities. This is the first example of metal-catalyzed asymmetric transformations of the in situ generated p-QMs, avoiding using pre-synthesized p-QMs requiring bulky 2,6-substitutions and highlighting a new dual catalytic activation with the chiral bis(oxazoline)-metal complex acting as a normal Lewis acid to activate the beta-ketoesters and a source of Bronsted acid responsible for generating the p-QMs in situ.
CHEMICAL COMMUNICATIONS
(2022)
Article
Cell Biology
Wencheng Zhu, Huiying Chu, Yajuan Zhang, Tianhang Luo, Hua Yu, Hongwen Zhu, Ye Liu, Hong Gao, Yun Zhao, Quanlin Li, Xiongjun Wang, Guohui Li, Weiwei Yang
Summary: Emerging evidence suggests that certain metabolic enzymes have the ability to phosphorylate protein substrates in addition to soluble metabolites, playing a role as protein kinases to regulate crucial cellular processes such as cell cycle and apoptosis. This study identifies the metabolic enzyme fructose 1,6-biphosphatase 1 (FBP1) as a protein phosphatase that dephosphorylates the serine (S) 32/36 of I kappa B alpha, inhibiting NF-kappa B activation. The findings also highlight the important role of FBP1-mediated I kappa B alpha dephosphorylation in suppressing colorectal tumorigenesis.
Article
Multidisciplinary Sciences
Anya V. Hess, Alexandra Auderset, Yair Rosenthal, Kenneth G. Miller, Xiaoli Zhou, Daniel M. Sigman, Alfredo Martinez-Garcia
Summary: The oxygen content of the oceans has declined due to climate change, especially in oxygen-deficient zones. Climate warming simulations predict the expansion of these zones until at least 2100. The response of ocean oxygenation on longer timescales remains uncertain.
Article
Chemistry, Organic
Rameshwar M. More, Archana B. Kadam, Vivek T. Humne, Subhash B. Junne
Summary: This article describes an unprecedented protocol for the synthesis of sulfur- and nitrogen-containing heteroaminals using a combination of molecular iodine and acetic acid as catalytic agents. It is the first report on the synthesis of acyclic heteroaminals, which are presumed to proceed via the formation of Schiff base and activation with molecular iodine. The synthesized products were characterized by spectral and mass analysis and obtained in good yield.
JOURNAL OF HETEROCYCLIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Sunil Gaikwad, Milind Gaikwad, Pradeep D. Lokhande
Summary: The developed method allows for the chemoselective aromatization of tetrahydro-beta-carboline with selective nondeallylation O-allyl groups using iodine in dimethyl sulfoxide/H2O2. It offers a convergent approach towards oxidative aromatization with selective deallylation of O-allyl-tetrahydro-beta-carboline, showing cheap catalyst, easy work up, normal reaction conditions, and high selectivity.
JOURNAL OF HETEROCYCLIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Sourav Biswas, Zahra A. Tabasi, Louise N. Dawe, Yuming Zhao, Graham J. Bodwell
Summary: The synthesis of anti-[1](1,6)naphthaleno[1](1,6)naphthalenophane (3) was achieved through a two-directional contractive annulation of [2.2]paracyclophane. This [1.1]cyclophane exhibits a high strain and structural distortion, but it was found to be unreactive towards cycloaddition partners (TCNE, DMAD) and under UV irradiation.
Article
Chemistry, Multidisciplinary
Raphael Robidas, Claude Y. Y. Legault
Summary: Halogen bond donors have made significant contributions to catalysis in recent years, and their development is highly active. Particularly, numerous iodine-based halogen bond donors have been developed and used for promoting various reactions through coordinating carbonyl groups, which are a common activation mode in catalysis. Computational data now suggests the possibility of an alternative activation mode, through direct pi-complexation, for unsaturated carbonyl substrates. Additionally, solvent polarity is found to have a significant impact on the preferred mode of activation, implying the potential for a mechanistic switch through solvent variation. These findings could have a profound impact on the development of the next generation of halogen bond donor catalysts.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Dengke Li, Weiming Hu
Summary: An efficient and practical method for the oxidative aromatization of pyrazolidin-3-ones and pyrazolines has been developed using iodine as a catalyst under metal-free, additive-free and external-oxidant-free conditions. The reaction showed good yields and tolerance towards various functional groups. This methodology is particularly useful for the synthesis of functionalized arylpyrazole derivatives and the development of pharmaceutical candidates.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Dengke Li
Summary: A general and straightforward iodine-catalyzed oxidative dehydrogenation system has been investigated for the synthesis of N-heteroarenes from saturated five and six-membered N-heterocycles. This system allows for the metal-free, additive-free, and external-oxidant-free synthesis of indole, (iso)quinoline, and beta-carboline analogues with moderate to good yields and broad functional group compatibility. The use of DMSO as both solvent and oxidant source in the transformation has been supported by preliminary mechanistic investigations. These synthetic strategies can be efficiently utilized for the elaboration of natural products.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Changhui Dai, Yijie Shen, Yifan Wei, Ping Liu, Peipei Sun
Summary: The dioxygenation of alkenes through the combination of electrochemical synthesis and aerobic oxidation presents a green and efficient method for the synthesis of alpha-oxygenated ketones. The protocol, which uses air as the oxygen source and excludes transition metals, is compatible with a wide range of alkenes and N-hydroxyimides, yielding moderate to high amounts of alpha-oxygenated ketones.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
M. Shahid, A. J. Punnya, Sakamuri Sarath Babu, Subhendu Sarkar, Purushothaman Gopinath
Summary: We have developed a dual palladium-photoredox-catalyzed acylation reaction using molecular oxygen as a green oxidant for highly regioselective modification of carbazoles and indolines. This method demonstrates a broad substrate scope and excellent functional group tolerance. We have further showcased its versatility through late-stage functionalization of a carprofen drug derivative, manipulation of products, and gram-scale synthesis of the desired acylated compounds.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Philipp Natho, Lewis A. T. Allen, Philip J. Parsons
Summary: The transition-metal-free total syntheses of three oxygenated carbazole natural products glycoborine, carbazomycin A and carbazomycin B are described. The key step involves an NBS-mediated cyclobutanol ring expansion to 4-tetralones for the preparation of the tricyclic carbazole core.
Article
Chemistry, Organic
Subhadip Maiti, Tirtha Mandal, Barada Prasanna Dash, Jyotirmayee Dash
Summary: This study presents a general palladium-catalyzed monoacylation method for carbazoles, using toluene derivatives as both acyl source and organic solvent, with NHPI and oxygen as cocatalyst and sole oxidant, respectively. The regioselective acylation at C-8 position of monosubstituted N-pyridylcarbazoles is achieved using aldehyde as the acyl source, indicating a highly site-selective acylation proceeding through a radical process.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Kohei Yasuda, Shigekazu Ito
Summary: In this paper, the extension of π-system with phosphinine was investigated by synthesizing 12-phosphatetraphene and 9-phosphabenzo[f]tetraphene. This study is important for developing heavier congeners of polyaromatic hydrocarbons and understanding the effects of trifluoromethyl.
Article
Chemistry, Organic
Geeta Devi Yadav, Pooja Chaudhary, Balaram Pani, Surendra Singh
Summary: Chiral transition metal complexes with privileged ligands are efficient catalysts for various asymmetric organic transformations. Transition metal complexes of C1-symmetric pyrrolidine-based ligands have been widely used in asymmetric organic reactions. However, a comprehensive review article on the transition metal complexes of chiral C1-symmetric pyrrolidine-based ligands derived from (L)-proline has not been published.
TETRAHEDRON LETTERS
(2024)
