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Beilstein Journal of Organic Chemistry

Olga Eguaogie, Joseph S Vyle, Patrick F Conlon, Manuela A Gîlea, Yipei Liang
The application of mechanical force to induce the formation and cleavage of covalent bonds is a rapidly developing field within organic chemistry which has particular value in reducing or eliminating solvent usage, enhancing reaction rates and also in enabling the preparation of products which are otherwise inaccessible under solution-phase conditions. Mechanochemistry has also found recent attention in materials chemistry and API formulation during which rearrangement of non-covalent interactions give rise to functional products...
2018: Beilstein Journal of Organic Chemistry
Eirinaios I Vrettos, Gábor Mező, Andreas G Tzakos
Cancer is the second leading cause of death affecting nearly one in two people, and the appearance of new cases is projected to rise by >70% by 2030. To effectively combat the menace of cancer, a variety of strategies have been exploited. Among them, the development of peptide-drug conjugates (PDCs) is considered as an inextricable part of this armamentarium and is continuously explored as a viable approach to target malignant tumors. The general architecture of PDCs consists of three building blocks: the tumor-homing peptide, the cytotoxic agent and the biodegradable connecting linker...
2018: Beilstein Journal of Organic Chemistry
Ahmet Altun, Frank Neese, Giovanni Bistoni
The local energy decomposition (LED) analysis allows for a decomposition of the accurate domain-based local pair natural orbital CCSD(T) [DLPNO-CCSD(T)] energy into physically meaningful contributions including geometric and electronic preparation, electrostatic interaction, interfragment exchange, dynamic charge polarization, and London dispersion terms. Herein, this technique is employed in the study of hydrogen-bonding interactions in a series of conformers of water and hydrogen fluoride dimers. Initially, DLPNO-CCSD(T) dissociation energies for the most stable conformers are computed and compared with available experimental data...
2018: Beilstein Journal of Organic Chemistry
Andrea Angelo Pierluigi Tripodi, Szilárd Tóth, Kata Nóra Enyedi, Gitta Schlosser, Gergely Szakács, Gábor Mező
Cyclic NGR peptides as homing devices are good candidates for the development of drug conjugates for targeted tumor therapy. In our previous study we reported that the Dau=Aoa-GFLGK(c[KNGRE]-GG-)-NH2 conjugate has a significant antitumor activity against both CD13+ HT-1080 human fibrosarcoma and CD13- but integrin positive HT-29 human colon adenocarcinoma cells. However, it seems that the free ε-amino group of Lys in the cycle is not necessary for the biological activity. Therefore, we developed novel cyclic NGR peptide-daunomycin conjugates in which Lys was replaced by different amino acids (Ala, Leu, Nle, Pro, Ser)...
2018: Beilstein Journal of Organic Chemistry
Jeroen S Dickschat, Ersin Celik, Nelson L Brock
The volatiles emitted by agar plate cultures of three genome sequenced fungal strains from the genus Aspergillus were analysed by GC-MS. All three strains produced terpenes for which a biosynthetic relationship is discussed. The obtained data were also correlated to genetic information about the encoded terpene synthases for each strain. Besides terpenes, a series of aromatic compounds and volatiles derived from fatty acid and branched amino acid metabolism were identified. Some of these compounds have not been described as fungal metabolites before...
2018: Beilstein Journal of Organic Chemistry
Fabiana Pandolfi, Isabella Chiarotto, Marta Feroci
The electrochemical reduction of 2-(2,2-dibromovinyl)naphthalene in a DMF solution (Pt cathode) yields selectively 2-ethynylnaphthalene or 2-(bromoethynyl)naphthalene in high yields, depending on the electrolysis conditions. In particular, by simply changing the working potential and the supporting electrolyte, the reaction can be directed towards the synthesis of the terminal alkyne (Et4 NBF4 ) or the bromoalkyne (NaClO4 ). This study allowed to establish that 2-(bromoethynyl)naphthalene can be converted into 2-ethynylnaphthalene by cathodic reduction...
2018: Beilstein Journal of Organic Chemistry
Meng Gao, Wenting Zhao, Hongyi Zhao, Ziyun Lin, Dongfeng Zhang, Haihong Huang
A straightforward and one-pot synthesis of pyrrolo[3,4- c ]pyrrole-1,3-diones via Ag(I)-catalyzed 1,3-dipolar cycloaddition of azomethine ylides with N -alkyl maleimide, followed by readily complete oxidation with DDQ, has been successfully developed. Further transformation with alkylamine/sodium alkoxide alcohol solution conveniently afforded novel polysubstituted pyrroles in good to excellent yields. This methodology for highly functionalized pyrroles performed well over a broad scope of substrates. It is conceivable that this efficient construction method for privileged pyrrole scaffolds could deliver more active compounds for medicinal chemistry research...
2018: Beilstein Journal of Organic Chemistry
Amarendar Reddy Maddirala, Peter R Andreana
The synthesis of spiro[indoline-3,2'-pyrrole]-2,5'(1' H )-diones and spiro[indoline-3,2'-pyrrolidine]-2,5'-diones, via a post-Ugi-domino transamidation/cyclization sequential process, has been achieved in three sequential steps utilizing a one-pot reaction protocol. The variation in carboxylic acid substrates allows for the generation of new chiral racemic quaternary carbon centers under basic conditions providing molecular diversity and a small library of spirocyclic oxindoles.
2018: Beilstein Journal of Organic Chemistry
Feng-Ming Xie, Qingdong Ou, Qiang Zhang, Jiang-Kun Zhang, Guo-Liang Dai, Xin Zhao, Huai-Xin Wei
Two novel D-A bipolar blue phosphorescent host materials based on phenothiazine-5,5-dioxide: 3-(9 H -carbazol-9-yl)-10-ethyl-10 H -phenothiazine-5,5-dioxide (CEPDO) and 10-butyl-3-(9 H -carbazol-9-yl)-10 H -phenothiazine-5,5-dioxide (CBPDO) were synthesized and characterized. The photophysical, electrochemical and thermal properties were systematically investigated. CEPDO and CBPDO not only have a high triplet energy but also show a bipolar behavior. Moreover, their fluorescence emission peaks are in the blue fluorescence region at 408 nm and the fluorescence quantum efficiency (Φ) of CEPDO and CBPDO were 62...
2018: Beilstein Journal of Organic Chemistry
Tatiana Golub, James Y Becker
In general, bisamides derived from diamines and involving 3 and 4 methylene groups as spacers between the two amide functionalities behave similar to monoamides upon anodic oxidation in methanol/LiClO4 because both types undergo majorly mono- and dimethoxylations at the α-position to the N atom. However, in cases where the spacer contains two methylene groups only the anodic process leads mostly to CH2 -CH2 bond cleavage to afford products of type RCONHCH2 OCH3 . Moreover, upon replacing LiClO4 with Et4 NBF4 an additional fragmentation type of product was generated from the latter amides, namely RCONHCHO...
2018: Beilstein Journal of Organic Chemistry
Bettina Riedl, Walther Schmid
Synthetic approaches towards N -acetylgalactosamine (GalNAc) have been attracting considerable interest since this compound is known for its pivotal role in cell-cell interaction and receptor induced cell signaling. Herein, we present a synthetic route in which two of the four stereogenic centers present in the target compound are derived from enantiopure tartaric acid being selectively converted to epoxy alcohols. The key step is the Pd-catalyzed, stereo- and regioselective epoxide opening and subsequent nucleophilic substitution of an azide functionality...
2018: Beilstein Journal of Organic Chemistry
Natalia Soldatova, Pavel Postnikov, Olga Kukurina, Viktor V Zhdankin, Akira Yoshimura, Thomas Wirth, Mekhman S Yusubov
A facile synthesis of diaryliodonium salts utilizing Oxone as versatile and cheap oxidant has been developed. This method shows wide applicability and can be used for the preparation of iodonium salts containing electron-donating or electron-withdrawing groups in good yields. In addition, this procedure can be applied to the preparation of symmetric iodonium salts directly from arenes via a one-pot iodination-oxidation sequence.
2018: Beilstein Journal of Organic Chemistry
Elias Christoforides, Andreas Papaioannou, Kostas Bethanis
The role of beta-cyclodextrin (β-CD) in cholesterol removal primarily from mammalian cells and secondly from dairy products has been studied thoroughly in recent years. Although the physicochemical characterization of the inclusion compound of cholesterol in β-CD has been achieved by various methods, no crystal structure has been determined so far. We report here the crystal structure of the inclusion compound of cholesterol in β-CD. The inclusion complex crystallizes in the triclinic space group P 1 forming head-to-head dimers which are stacked along the c -axis...
2018: Beilstein Journal of Organic Chemistry
Satu Mikkola, Tuomas Lönnberg, Harri Lönnberg
Nucleic acids that store and transfer biological information are polymeric diesters of phosphoric acid. Cleavage of the phosphodiester linkages by protein enzymes, nucleases, is one of the underlying biological processes. The remarkable catalytic efficiency of nucleases, together with the ability of ribonucleic acids to serve sometimes as nucleases, has made the cleavage of phosphodiesters a subject of intensive mechanistic studies. In addition to studies of nucleases by pH-rate dependency, X-ray crystallography, amino acid/nucleotide substitution and computational approaches, experimental and theoretical studies with small molecular model compounds still play a role...
2018: Beilstein Journal of Organic Chemistry
Zhensheng Zhao, Graham K Murphy
Allyl and vinyl chlorides represent important structural motifs in organic chemistry. Herein is described the chemoselective and regioselective reaction of aryl- and α-substituted phenylallenes with the hypervalent iodine (HVI) reagent 1-chloro-1,2-benziodoxol-3-one. The reaction typically results in vicinal dichlorides, except with proton-containing α-alkyl substituents, which instead give chlorinated dienes as the major product. Experimental evidence suggests that a radical mechanism is involved.
2018: Beilstein Journal of Organic Chemistry
Jingbo Yu, Zikun Hong, Xinjie Yang, Yu Jiang, Zhijiang Jiang, Weike Su
A mechanically-activated chemoselective Heck coupling for the synthesis of 3-vinylindazoles has been developed with the aid of catalytic amounts of TBAB and NaBr as both dehalogenation restrainer and grinding auxiliary. After tuning of the chemical conditions and mechanical parameters, a series of non-activated 3-bromoindazoles and a broad scope of olefins worked well to give the corresponding coupling products in good to excellent yields. A further application of this protocol was performed in a two-step mechanochemical Heck/Migita cross coupling, which provided a highly efficient route for the synthesis of axitinib...
2018: Beilstein Journal of Organic Chemistry
Kartik Temburnikar, Katherine L Seley-Radtke
C-nucleosides have intrigued biologists and medicinal chemists since their discovery in 1950's. In that regard, C-nucleosides and their synthetic analogues have resulted in promising leads in drug design. Concurrently, advances in chemical syntheses have contributed to structural diversity and drug discovery efforts. Convergent and modular approaches to synthesis have garnered much attention in this regard. Among them nucleophilic substitution at C1' has seen wide applications providing flexibility in synthesis, good yields, the ability to maneuver stereochemistry as well as to incorporate structural modifications...
2018: Beilstein Journal of Organic Chemistry
Sabine Schuster, Beáta Biri-Kovács, Bálint Szeder, Viktor Farkas, László Buday, Zsuzsanna Szabó, Gábor Halmos, Gábor Mező
Gonadotropin releasing hormone-III (GnRH-III), a native isoform of the human GnRH isolated from sea lamprey, specifically binds to GnRH receptors on cancer cells enabling its application as targeting moieties for anticancer drugs. Recently, we reported on the identification of a novel daunorubicin-GnRH-III conjugate (GnRH-III-[4 Lys(Bu), 8 Lys(Dau=Aoa)] with efficient in vitro and in vivo antitumor activity. To get a deeper insight into the mechanism of action of our lead compound, the cellular uptake was followed by confocal laser scanning microscopy...
2018: Beilstein Journal of Organic Chemistry
Márton Bojtár, Péter Zoltán Janzsó-Berend, Dávid Mester, Dóra Hessz, Mihály Kállay, Miklós Kubinyi, István Bitter
Background: Nucleotides are essential molecules in living systems due to their paramount importance in various physiological processes. In the past years, numerous attempts were made to selectively recognize and detect these analytes, especially ATP using small-molecule fluorescent chemosensors. Despite the various solutions, the selective detection of ATP is still challenging due to the structural similarity of various nucleotides. In this paper, we report the conjugation of a uracil nucleobase to the known 4'-dimethylamino-hydroxyflavone fluorophore...
2018: Beilstein Journal of Organic Chemistry
Jeroen S Dickschat, Tao Wang, Marc Stadler
The volatiles emitted by agar plate cultures of the xylarialean fungus Hypoxylon invadens were investigated by use of a closed loop stripping apparatus in combination with GC-MS. Several aromatic compounds were found that could only be identified by comparison to all possible constitutional isomers with different ring substitution patterns. For the set of identified compounds a plausible biosynthetic scheme was suggested that gives further support for the assigned structures.
2018: Beilstein Journal of Organic Chemistry
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