- Me3SI-promoted chemoselective deacetylation: a general and mild protocol
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A Me3SI-mediated simple and efficient protocol for the chemoselective deprotection of acetyl groups has been developedviaemploying KMnO4as an additive. This chemoselective deacetylation is amenable to a wide range of substrates, tolerating diverse and sensitive functional groups in carbohydrates, amino acids, natural products, heterocycles, and general scaffolds. The protocol is attractive because it uses an environmentally benign reagent system to perform quantitative and clean transformations under ambient conditions.
- Gurawa, Aakanksha,Kashyap, Sudhir,Kumar, Manoj
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p. 19310 - 19315
(2021/06/03)
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- Synthesis and Structure-Activity Relationships of Ring-Opened Bengamide Analogues against Methicillin-Resistant Staphylococcus aureus?
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Methicillin-resistant Staphylococcus aureus (MRSA) has become a major threat on public health because of the increase of clinically isolated strains that exhibit resistance to many antibiotics. Therefore, development of new antibiotics for the treatment of MRSA infection is a sustained challenge. We have previously identified a ring-opened bengamide analogue L472-2 that displays moderate activity against the growth of S. aureus. In our previous work, we started from L472-2 and identified a class of analogues containing alkynyl groups which have the potential to activate SaClpP activity but moderate antibacterial activity. Herein, we focused on the antibacterial activity of L472-2, and a novel series of ring-opened bengamide analogues were synthesized and their activities were evaluated against MRSA. By conducting a compact analysis of the structure-activity relationships (SAR) of these analogues, we found that an adamantane ethanol ester bengamide 2j showed excellent antibacterial activity towards six S. aureus strains, including MRSA, while it does not activate ClpP. Therefore, these bengamide analogues represent a new class of candidates that suppress MRSA viability.
- Yu, Chen-Xi,Wei, Bing-Yan,Kong, Xue-Qing,Yang, Cai-Guang,Nan, Fa-Jun
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supporting information
p. 671 - 676
(2021/02/12)
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- Drastic fluorine effect: Complete reversal of the selectivity in the Au-catalyzed hydroalkoxylation reaction of fluorinated haloalkynes
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The gold-catalyzed hydration reaction of haloalkynes is highly regioselective producing 2-halomethylketones as the sole products. Herein, we document a drastic fluorine effect where the reaction of 1-halo-3,3-difluoroalkynes as substrates leads to a complete reversal of selectivity and produces 3,3-difluoroesters as the unique products.
- Cloutier, Mélissa,Mamone, Marius,Paquin, Jean-Fran?ois
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supporting information
p. 5969 - 5972
(2020/06/04)
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- MITOCHONDRIA-TARGETING PEPTIDES
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Disclosed are analogs of SBT-20. The compounds are useful for the treatment and prevention of ischemia-reperfusion injury (e.g., cardiac ischemia-reperfusion injury) or myocardial infarction.
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Page/Page column 70; 71
(2020/07/14)
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- Pd-Catalyzed intermolecular C-H bond arylation reactions: Effect of bulkiness of carboxylate ligands
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A bulky carboxylic acid bearing one 1-adamantylmethyl and two methyl substituents at the α-position is demonstrated to work as an efficient carboxylate ligand source in Pd-catalyzed intermolecular C(sp2)-H bond arylation reactions. The reactions proceeded smoothly under mild conditions, taking advantage of the steric bulk of the carboxylate ligands.
- Tanji, Yutaka,Hamaguchi, Ryo,Tsuji, Yasushi,Fujihara, Tetsuaki
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supporting information
p. 3843 - 3846
(2020/04/15)
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- Binding study on 1-adamantylalkyl(benz)imidazolium salts to cyclodextrins and cucurbit[n]urils
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Multitopic guests are used as key components of molecular triggers, switchers, sensors, or reactors in recent supramolecular chemistry studies. The increasing complexity of these compounds correlates with the need for versatile, synthetically available binding motifs (building blocks) with tuneable supramolecular properties. The utilisation of a favoured 1-adamantylmethyl moiety in ammonium, imidazolium and pyridinium salts is sometimes restricted by synthetic difficulties most likely related to the adamantane cage bulkiness. Therefore, we prepared a series of new adamantylated (benz)imidazolium salts with longer flexible linkers between the adamantane cage and cationic moiety. We tested the supramolecular properties of these binding motifs towards the natural cyclodextrins α-CD, β-CD and γ-CD and cucurbit[n]urils (n= 7, 8) using NMR, mass spectrometry and titration calorimetry. All tested guests formed 1:1 complexes with the abovementioned hosts, retaining binding strengths, selectivity, and complex geometries in comparison to the parent methylene-linked homologues. We did not confirm our original concern that longer linkers would negatively affect the binding strength towards CBns due to the reduction in the ion-dipole interaction contribution. Therefore, we believe that adamantylalkyl imidazolium binding motifs can be used for multitopic supramolecular guest construction.
- Jelínková, Kristyna,Kova?evi?, Jelica,Wrzecionková, Eva,Prucková, Zdeňka,Rouchal, Michal,Dastychová, Lenka,Vícha, Robert
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p. 7071 - 7079
(2020/05/16)
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- Regioselective Gold-Catalyzed Hydration of CF3- and SF5-alkynes
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The regioselective gold-catalyzed hydration of CF3- and SF5-alkynes is described. The corresponding trifluoromethylated and pentasulfanylated ketones are obtained in up to 91% yield as single regioisomers showcasing the use of CF3 and SF5 as highly efficient directing groups in this reaction. Notably, this transformation represents the first use of CF3- and SF5-alkynes in gold catalysis.
- Cloutier, Mélissa,Roudias, Majdouline,Paquin, Jean-Fran?ois
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supporting information
p. 3866 - 3870
(2019/05/24)
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- Bridged bicyclic 2,3-dioxabicyclo[3.3.1]nonanes as antiplasmodial agents: Synthesis, structure-activity relationships and studies on their biomimetic reaction with Fe(II)
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Despite recent advancements in its control, malaria is still a deadly parasitic disease killing millions of people each year. Progresses in combating the infection have been made by using the so-called artemisinin combination therapies (ACTs). Natural and synthetic peroxides are an important class of antimalarials. Here we describe a new series of peroxides synthesized through a new elaboration of the scaffold of bicyclic-fused/bridged synthetic endoperoxides previously developed by us. These peroxides are produced by a straightforward synthetic protocol and are characterized by submicromolar potency when tested against both chloroquine-sensitive and chloroquine-resistant Plasmodium falciparum strains. To investigate their mode of action, the biomimetic reaction of the representative compound 6w with Fe(II) was studied by EPR and the reaction products were characterized by NMR. Rationalization of the observed structure-activity relationship studies was performed by molecular docking. Taken together, our data robustly support the hypothesized mode of activation of peroxides 6a-cc and led to the definition of the key structural requirements responsible for the antiplasmodial potency. These data will pave the way in future to the rational design of novel optimized antimalarials suitable for in vivo investigation.
- D'Alessandro, Sarah,Alfano, Gloria,Di Cerbo, Luisa,Brogi, Simone,Chemi, Giulia,Relitti, Nicola,Brindisi, Margherita,Lamponi, Stefania,Novellino, Ettore,Campiani, Giuseppe,Gemma, Sandra,Basilico, Nicoletta,Taramelli, Donatella,Baratto, Maria Camilla,Pogni, Rebecca,Butini, Stefania
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supporting information
(2019/06/13)
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- Multiple Halogenation of Aliphatic C?H Bonds within the Hofmann–L?ffler Manifold
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An innovative approach to position-selective polyhalogenation of aliphatic hydrocarbon bonds is presented. The reaction proceeded within the Hofmann-L?ffler manifold with amidyl radicals as the sole mediators to induce selective 1,5- and 1,6-hydrogen-atom transfer followed by halogenation. Multiple halogenation events of up to four innate C?H bond functionalizations were accomplished. The broad applicability of this new entry into polyhalogenation and the resulting synthetic possibilities were demonstrated for a total of 27 different examples including mixed halogenations.
- Del Castillo, Estefanía,Martínez, Mario D.,Bosnidou, Alexandra E.,Duhamel, Thomas,O'Broin, Calvin Q.,Zhang, Hongwei,Escudero-Adán, Eduardo C.,Martínez-Belmonte, Marta,Mu?iz, Kilian
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supporting information
p. 17225 - 17229
(2018/11/10)
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- Preparative synthesis of vinyl diamondoids
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We describe a convenient four-step preparation of 1-vinyl adamantane, 1-vinyl diamantane, and 4,9-divinyl diamantane from the respective diamondoid acetic acids in 50-80% isolated yields involving esterification, reduction, and hydrobromination/dehydrobromination. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
- Fokin, Andrey A.,Butova, Ekaterina D.,Barabash, Anastasiya V.,Huu, Nhan N.,Tkachenko, Boryslav A.,Fokina, Natalie A.,Schreiner, Peter R.
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p. 1772 - 1777
(2013/05/21)
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- Discovery of adamantane based highly potent HDAC inhibitors
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Herein, we report the development of highly potent HDAC inhibitors for the treatment of cancer. A series of adamantane and nor-adamantane based HDAC inhibitors were designed, synthesized and screened for the inhibitory activity of HDAC. A number of compounds exhibited GI50 of 10-100 nM in human HCT116, NCI-H460 and U251 cancer cells, in vitro. Compound 32 displays efficacy in human tumour animal xenograft model.
- Gopalan, Balasubramanian,Ponpandian, Thanasekaran,Kachhadia, Virendra,Bharathimohan, Kuppusamy,Vignesh, Radhakrishnan,Sivasudar, Velaiah,Narayanan, Shridhar,Mandar, Bhonde,Praveen, Rajendran,Saranya, Nithyanandan,Rajagopal, Sriram,Rajagopal, Sridharan
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p. 2532 - 2537
(2013/06/27)
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- ACETAL COMPOUNDS AND THEIR PREPARATION, POLYMERS, RESIST COMPOSITIONS AND PATTERNING PROCESS
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An acetal compound of formula (1) is provided wherein R1 is H, methyl or trifluoromethyl, R2 is a monovalent C1-C10 hydrocarbon group, R3 and R4 are H or a monovalent C1-C10 hydrocarbon group, R2 and R3 may together form an aliphatic hydrocarbon ring, and X1 is a single bond or a divalent C1-C4 hydrocarbon group. A polymer comprising recurring units derived from the acetal compound is used as a base resin to formulate a resist composition which exhibits a high resolution when processed by micropatterning technology, especially ArF lithography.
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- Deprotection of benzyl ethers using 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) under photoirradiation
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The deprotection of benzyl ethers was effectively realized in the presence of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) in MeCN under photoirradiation using a long wavelength UV light.
- Rahim, Mohammad Abdur,Matsumura, Shuichi,Toshima, Kazunobu
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p. 7307 - 7309
(2007/10/03)
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- Scope and Mechanism of Deprotection of Carboxylic Esters by Bis(tributyltin) Oxide
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Methyl and ethyl esters of aliphatic and aromatic carboxylic acids as well as benzyl carboxylates, thiol esters and double esters such as (pivaloyloxy)methyl carboxylates have been successfully cleaved with bis(tributyltin) oxide to give the free carboxylic acids in good yields.The reaction is carried out in aprotic solvents under essentially neutral conditions and thus this method can serve as an ideal procedure for the cleavages of esters with other functional groups and/or protecting groups acid and/or base sensitive.We demonstrated that the reaction displays a high level of chemoselectivity between methyl and ethyl esters versus tert-butyl esters and γ-lactones.Bis(tributyltin) oxide is also a highly efficient reagent for the cleavage of acetates of primary and secondary alcohols and phenols.The limitations we found in the use of this reagent include the lack of cleavage of esters sterically hindered around the carboxyl carbon and the carbinol group (i.e., esters of tertiary alcohols) and in carboxylic esters that contain a fluoroalkyl substituent.A resonable mechanistic explanation is discussed to account for the reaction pathway of the acyloxygen cleavage of (-)-(1R)-menthyl acetate.
- Salomon, Claudio J.,Mata, Ernesto G.,Mascaretti, Oreste A.
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p. 7259 - 7266
(2007/10/02)
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