54981-87-2Relevant academic research and scientific papers
Nickel-Catalyzed C(sp3)-C(sp3) Cross-Electrophile Coupling of in Situ Generated NHP Esters with Unactivated Alkyl Bromides
Kang, Kai,Weix, Daniel J.
supporting information, p. 2853 - 2857 (2022/05/03)
The formation of C(sp3)-C(sp3) bonds by cross-coupling remains a challenge in synthesis. Here, we demonstrate a two-step, one-pot protocol for the in situ generation of N-hydroxyphthalimide esters and their nickel-catalyzed cross-electrophile coupling with unactivated alkyl bromides for the construction of 1°/1 ° C(sp3)-C(sp3) bonds. The conditions tolerate an array of functional groups, and mechanistic studies indicate that both substrates are converted to alkyl radicals during the reaction.
Aqueous Benzylic C-H Trifluoromethylation for Late-Stage Functionalization
Guo, Shuo,AbuSalim, Deyaa I.,Cook, Silas P.
supporting information, p. 12378 - 12382 (2018/10/05)
The installation of trifluoromethyl groups has become an essential step across a number of industries such as agrochemicals, drug discovery, and materials. Consequently, the rapid introduction of this critical functional group in a predictable fashion would benefit current practitioners in those fields. This communication describes a mild trifluoromethylation of benzylic C-H bonds with high selectivity for the least hindered hydrogen atom. The reaction provides monotrifluoromethylation and proceeds in an environmentally friendly acetone/water solvent system. The method can be used to install benzylic trifluoromethyl groups on highly functionalized drug molecules.
Asymmetric Photocatalytic C-H Functionalization of Toluene and Derivatives
Mazzarella, Daniele,Crisenza, Giacomo E. M.,Melchiorre, Paolo
supporting information, p. 8439 - 8443 (2018/07/25)
Reported herein is a visible-light-mediated organocatalytic direct C-H functionalization of toluene derivatives to afford enantioenriched β-benzylated aldehydes from the corresponding enals. The process combines the oxidative power of a chiral excited-state iminium ion and the basic nature of its counteranion to trigger the generation of benzylic radicals by means of a sequential multisite proton-coupled electron transfer mechanism. This study shows that feedstock chemicals generally used as solvents, such as toluene and xylene derivatives, can be used as substrates for making chiral molecules with high enantioselectivity.
Catalytic Access to Alkyl Bromides, Chlorides and Iodides via Visible Light-Promoted Decarboxylative Halogenation
Candish, Lisa,Standley, Eric A.,Gómez-Suárez, Adrián,Mukherjee, Satobhisha,Glorius, Frank
supporting information, p. 9971 - 9974 (2016/07/19)
Herein is reported the catalytic, visible light-promoted, decarboxylative halogenation (bromination, chlorination, and iodination) of aliphatic carboxylic acids. This operationally-simple reaction tolerates a range of functional groups, proceeds at room temperature, and is redox neutral. By employing an iridium photocatalyst in concert with a halogen atom source, the use of stoichiometric metals such as silver, mercury, thallium, and lead can be circumvented. This reaction grants access to valuable synthetic building blocks from the large pool of cheap, readily available carboxylic acids.
X-ray crystal structures of Enterococcus faecalis thymidylate synthase with folate binding site inhibitors
Catalano, Alessia,Luciani, Rosaria,Carocci, Alessia,Cortesi, Debora,Pozzi, Cecilia,Borsari, Chiara,Ferrari, Stefania,Mangani, Stefano
, p. 649 - 664 (2016/08/12)
Infections caused by Enterococcus faecalis (Ef) represent nowadays a relevant health problem. We selected Thymidylate synthase (TS) from this organism as a potential specific target for antibacterial therapy. We have previously demonstrated that species-specific inhibition of the protein can be achieved despite the relatively high structural similarity among bacterial TSs and human TS. We had previously obtained the EfTS crystal structure of the protein in complex with the metabolite 5-formyl-tetrahydrofolate (5-FTHF) suggesting the protein role as metabolite reservoir; however, protein–inhibitors complexes were still missing. In the present work we identified some inhibitors bearing the phthalimidic core from our in-house library and we performed crystallographic screening towards EfTS. We obtained two X-ray crystallographic structures: the first with a weak phthalimidic inhibitor bound in one subunit and 5-hydroxymethylene-6-hydrofolic acid (5-HMHF) in the other subunit; a second X-ray structure complex with methotrexate. The structural information achieved confirm the role of EfTS as an enzyme involved in the folate pool system and provide a structural basis for structure-based drug design.
Synthesis and pharmacological characterization of novel 6-fluorochroman derivatives as potential 5-HT(1A) receptor antagonists
Yasunaga, Tomoyuki,Kimura, Takenori,Naito, Ryo,Kontani, Toru,Wanibuchi, Fumikazu,Yamashita, Hiroshi,Nomura, Tamako,Tsukamoto, Shin-Ichi,Yamaguchi, Tokio,Mase, Toshiyasu
, p. 2765 - 2778 (2007/10/03)
A series of novel 6-fluorochroman derivatives was prepared and evaluated as antagonists for the 5-HT(1A) receptor. N-2-[[(6-Fluorochroman-8- yl)oxy]ethyl]-4-(4-methoxyphenyl)butylamine (3; J. Med. Chem. 1997, 40, 1252- 1257) was chosen as a lead, and structural modifications were done on the aliphatic portion of the chroman ring, the tether linking the middle amine and the terminal aromatic ring, the aromatic ring, and lastly the amine. Radioligand binding assays proved that the majority of the novel compounds behaved as good to excellent ligands at the 5-HT(1A) receptor, some of which were selective with respect to α1-adrenergic and D2-dopaminergic receptors. The antagonist activity of the compounds was assessed in the forskolinstimulated adenylate cyclase assays in CHO cells expressing the human 5-HT(1A) receptors. Among the modifications attempted, introduction of an oxo or an optically active hydroxy moiety at the chroman C-4 position was effective in ameliorating the receptor selectivity. Six analogues were selected through the in vitro screens and further evaluated for their in vivo activities. A 4-oxochroman derivative (31n), having a terminal 1,3- benzodioxole ring, demonstrated antagonist activities toward 8-OH-DPAT- induced behavioral and electrophysiological responses in rats.
Vinylation of benzylic quaternary ammonium salts catalyzed by palladium
Yi,Zhuangyu,Hongwen
, p. 245 - 247 (2007/10/02)
The palladium-catalyzed vinylation of benzylic tributylammonium salts with a variety of olefins has been studied. A possible free radical mechanism is proposed.
Mitsunobu-like Processes with a Novel Triphenylphosphine-Cyclic Sulfamide Betaine
Castro, Jose L.,Matassa, Victor G.,Ball, Richard G.
, p. 2289 - 2291 (2007/10/02)
An unprecedented adduct 10 between triphenylphosphine (TPP) and 3,3-dimethyl-1,2,5-thiadiazolidine 1,1-dioxide (8) is described, which can be regarded as a stable source of the (1+) species, and was utilized to efficiently promote the coupling betwe
Monocyclic Pteridine Analogues. Inhibition of Escherichia coli Dihydropteroate Synthase by 6-Amino-5-nitrosoisocytosines
Lever, O. William,Bell, Lawrence N.,McGuire, H. Michael,Ferone, Robert
, p. 1870 - 1874 (2007/10/02)
A variety of 5,6-disubstituted isocytosine derivatives were evaluated in vitro as inhibitors of dihydropteroate synthase from Escherichia coli.A number of 6-(alkylamino)-5-nitrosoisocytosines have in vitro potency equivalent with or superior to that of therapeutically effective sulfonamide inhibitors of the synthase.The sulfonamide drugs are known to complete for the p-aminobenzoic acid binding site of the synthase, and kinetic analysis of inhibition of the synthase by 6-(methylamino)-5-nitrosoisocytosine (16; I50 = 1.6 μM) and by the 6-(3-phenoxypropyl)amino analogue (33; I50 = 3.7 μM) indicated that the nitrosoisocytosine inhibitors compete with the pteridine substrate for the enzyme.Structure-activity studies demonstrated that the enzyme surface has a low tolerance for steric bulk in the region surrounding the isocytosine 6-amino function.However, this steric intolerance may be counterbalanced to a significant degree by positive allosteric interactions achieved by certain analogues that have a 6-(ω-phenylalkyl)amino substituent.For example, 6--5-nitrosoisocytosine (28) is as effective an inhibitor (I50 = 1.4 μM) as the 6-methylamino compound 16.Although several members of the 5-nitroso series were potent synthase inhibitors, none of the nitrosoisocytosines exhibited significant antibacterial activity.This observation may reflect poor transport of these compounds through the bacterial cell wall or, alternatively, may result from a rapid metabolic inactivation process.
