A semisynthesis of 3'-O-ethyl-5,6-dihydrospinosyn J based on the spinosyn A aglycone

• Kai Zhang,
• Shenglan Liu,
• Anjun Liu,
• Hongxin Chai,
• Jiarong Li and
• Lamusi A

Beilstein J. Org. Chem. 2017, 13, 2603–2609, doi:10.3762/bjoc.13.257

• to synthesize other rhamnose analogues. The structures of spinosad and spinetoram. Chemical modifications of spinosyn J and spinosyn L. Retrosynthetic analysis of 3'-O-ethyl-5,6-dihydrospinosyn J. Hydrolysis of spinosyn A and formation of the aglycone and D-forosamine. Synthesis of 3-O-ethyl-2,4-di-O

Synthesis of ergostane-type brassinosteroids with modifications in ring A

• Vladimir N. Zhabinskii,
• Darya A. Osiyuk,
• Yuri V. Ermolovich,
• Natalia M. Chaschina,
• Tatsiana S. Dalidovich,
• Miroslav Strnad and
• Vladimir A. Khripach

Beilstein J. Org. Chem. 2017, 13, 2326–2331, doi:10.3762/bjoc.13.229

• naturally occurring BS (e.g., epibrassinolide [8]) have found practical application in agriculture and thus are commercially available and a cheap source for further chemical modifications. As a part of our programme aimed at the study of BS biosynthesis, we focussed in the present investigation on the

Synthesis and photophysical properties of novel benzophospholo[3,2-b]indole derivatives

• Mio Matsumura,
• Mizuki Yamada,
• Atsuya Muranaka,
• Misae Kanai,
• Naoki Kakusawa,
• Daisuke Hashizume,
• Masanobu Uchiyama and
• Shuji Yasuike

Beilstein J. Org. Chem. 2017, 13, 2304–2309, doi:10.3762/bjoc.13.226

• may be associated with the low fluorescence quantum yields. Conclusion A series of novel indole-fused phospholes were synthesized by simple chemical modifications at the trivalent phosphorus center. These organophosphorus compounds generated a whole series of derivatives from only one precursor. The X

• ]indole 3. Chemical modifications of the phosphorus atom of 3. Selected bond length and angles. Absorption and fluorescence spectroscopy data.a Calculated HOMO and LUMO levels of phospholes. Supporting Information Supporting Information File 340: Experimental details, characterization data, and NMR

Difunctionalization of alkenes with iodine and tert-butyl hydroperoxide (TBHP) at room temperature for the synthesis of 1-(tert-butylperoxy)-2-iodoethanes

• Hao Wang,
• Cui Chen,
• Weibing Liu and
• Zhibo Zhu

Beilstein J. Org. Chem. 2017, 13, 2023–2027, doi:10.3762/bjoc.13.200

• applications and allow further chemical modifications, enabling the preparation of synthetically valuable molecules. Keywords: difunctionalization of alkenesiodine; iodination–peroxidation reaction; TBHP; Introduction Alkenes have attracted considerable interest in recent years as abundant, simple chemical

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

• ]. However, chemical complementation with mycolactone restored the typical M. ulcerans pathology for mycolactone-deficient strains [35]. Some chemical modifications were performed on the purified extracts showing that peracetylation or exhaustive double bond saturation by hydrogenation resulted in a total

Effect of uridine protecting groups on the diastereoselectivity of uridine-derived aldehyde 5’-alkynylation

• Raja Ben Othman,
• Mickaël J. Fer,
• Laurent Le Corre,
• Sandrine Calvet-Vitale and
• Christine Gravier-Pelletier

Beilstein J. Org. Chem. 2017, 13, 1533–1541, doi:10.3762/bjoc.13.153

• epigenetic modulators [9] or chemical tools [10][11]. Furthermore, they represent central monomers for oligonucleos(t)ide synthesis [12][13][14][15][16][17]. In the past decades, chemical modifications of these crucial building blocks have been extensively studied, both on the nucleobase itself and on the

Nitration of 5,11-dihydroindolo[3,2-b]carbazoles and synthetic applications of their nitro-substituted derivatives

• Roman A. Irgashev,
• Nikita A. Kazin,
• Gennady L. Rusinov and
• Valery N. Charushin

Beilstein J. Org. Chem. 2017, 13, 1396–1406, doi:10.3762/bjoc.13.136

• important nitro aromatic products with a wide range of applications [45]. Moreover, incorporation of the nitro group into aromatic or electron-rich heteroaromatic systems is an efficient synthetic tool for their chemical modifications. In this context, we wish to show the usefulness of the synthesized nitro

The effect of cyclodextrin complexation on the solubility and photostability of nerolidol as pure compound and as main constituent of cabreuva essential oil

• Joyce Azzi,
• Pierre-Edouard Danjou,
• David Landy,
• Steven Ruellan,
• Lizette Auezova,
• Hélène Greige-Gerges and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2017, 13, 835–844, doi:10.3762/bjoc.13.84

• characteristic is their ability to form inclusion complexes with poorly soluble guest molecules which are entrapped in the hydrophobic cavity of CDs. Chemical modifications of the hydroxy groups of CDs can be performed to obtain water-soluble CD derivatives like hydroxypropyl-β-CD (HP-β-CD), methylated CDs

Versatile synthesis of end-reactive polyrotaxanes applicable to fabrication of supramolecular biomaterials

• Atsushi Tamura,
• Asato Tonegawa,
• Yoshinori Arisaka and
• Nobuhiko Yui

Beilstein J. Org. Chem. 2016, 12, 2883–2892, doi:10.3762/bjoc.12.287

• methods of introducing functional groups at the threading CD moieties of PRXs are used. Among the various chemical modifications, the introduction of azide or alkynyl groups at the threading CDs of the PRX is particularly attractive, because these functional groups undergo efficient azide–alkyne Huisgen

Interactions between cyclodextrins and cellular components: Towards greener medical applications?

• Loïc Leclercq

Beilstein J. Org. Chem. 2016, 12, 2644–2662, doi:10.3762/bjoc.12.261

• templates for the generation of a wide range of molecular hosts through chemical modifications. ii) Modified cyclodextrins In order to meet specific requirements in the host–guest complex, chemical modifications make it possible to tailor CDs to a particular guest. The hydroxy groups serve as scaffolds on

Automated glycan assembly of a S. pneumoniae serotype 3 CPS antigen

• Markus W. Weishaupt,
• Stefan Matthies,
• Mattan Hurevich,
• Claney L. Pereira,
• Heung Sik Hahm and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2016, 12, 1440–1446, doi:10.3762/bjoc.12.139

• -automation chemical modifications and the loss of product, we assembled pneumococcal serotype 3 CPS structures utilizing glucose and glucuronic acid monosaccharide building blocks and thus avoided late-stage oxidations. Results and Discussion Mindful of this strategic framework, glucuronic acid building

Elucidation of a masked repeating structure of the O-specific polysaccharide of the halotolerant soil bacteria Azospirillum halopraeferens Au4

• Elena N. Sigida,
• Yuliya P. Fedonenko,
• Alexander S. Shashkov,
• Nikolay P. Arbatsky,
• Evelina L. Zdorovenko,
• Svetlana A. Konnova,
• Vladimir V. Ignatov and
• Yuriy A. Knirel

Beilstein J. Org. Chem. 2016, 12, 636–642, doi:10.3762/bjoc.12.62

• afforded complementary oligosaccharides, which identification shed light on the nature of the OPS irregularity and, combined with chemical analysis and NMR spectroscopic analysis data, enabled the structure elucidation of the OPS. Chemical modifications of the OPS, such as O-methylation or O-acetylation

• chemical modifications of the OPS into the corresponding derivatives were performed as described [35]. NMR spectra were obtained using an Avance II 600 MHz instrument (Bruker, Germany) at 30 °C in 99.95 % D2O using sodium 3-trimethylsilylpropanoate-2,2,3,3-d4 (δH 0.0, δC −1.6) as internal standard for

New synthetic strategies for xanthene-dye-appended cyclodextrins

• Milo Malanga,
• Andras Darcsi,
• Mihaly Balint,
• Gabor Benkovics,
• Tamas Sohajda and
• Szabolcs Beni

Beilstein J. Org. Chem. 2016, 12, 537–548, doi:10.3762/bjoc.12.53

• sorting, in photodynamic therapy and in colorimetric enzymatic tests (ELISA). Although it is possible to modify xanthene dyes with specific functional groups (e.g., isothiocyanates, maleimide, succinimidyl), enabling them to react with amine groups, such chemical modifications dramatically affect the cost

Donor–acceptor type co-crystals of arylthio-substituted tetrathiafulvalenes and fullerenes

• Xiaofeng Lu,
• Jibin Sun,
• Shangxi Zhang,
• Longfei Ma,
• Lei Liu,
• Hui Qi,
• Yongliang Shao and
• Xiangfeng Shao

Beilstein J. Org. Chem. 2015, 11, 1043–1051, doi:10.3762/bjoc.11.117

• between TTFs and fullerenes are key factors that give rise to the effective surface contact for the stabilization of the resulting supramolecular structures. Because pristine TTF cannot form good enough surface contact with fullerenes due to the shape and size mismatch [42], chemical modifications of TTF

Copper ion salts of arylthiotetrathiafulvalenes: synthesis, structure diversity and magnetic properties

• Longfei Ma,
• Jibin Sun,
• Xiaofeng Lu,
• Shangxi Zhang,
• Hui Qi,
• Lei Liu,
• Yongliang Shao and
• Xiangfeng Shao

Beilstein J. Org. Chem. 2015, 11, 850–859, doi:10.3762/bjoc.11.95

• the discovery of highly conducting charge-transfer (CT) complex TTF·TCNQ [3] and the first organic superconductor (TMTSF)2X [4], the chemical modifications on TTF are traditionally aimed at the creation of organic conductors with various electronic ground states [5][6][7][8][9][10]. It has been well

Orthogonal dual-modification of proteins for the engineering of multivalent protein scaffolds

• Michaela Mühlberg,
• Michael G. Hoesl,
• Christian Kuehne,
• Jens Dernedde,
• Nediljko Budisa and
• Christian P. R. Hackenberger

Beilstein J. Org. Chem. 2015, 11, 784–791, doi:10.3762/bjoc.11.88

• paper was the development of a robust synthetic methodology that allows the site-specific attachment of two distinct chemical modifications to a given protein, which can be used to target multivalent interactions. As a protein scaffold we selected the thermophilic lipase from Thermoanaerobacter

Synthesis of graft polyrotaxane by simultaneous capping of backbone and grafting from rings of pseudo-polyrotaxane

• Kazuaki Kato,
• Katsunari Inoue,
• Masabumi Kudo and
• Kohzo Ito

Beilstein J. Org. Chem. 2014, 10, 2573–2579, doi:10.3762/bjoc.10.269

• used to dissolve polyrotaxanes and to enable the intramolecular mobility [5][6]. For the same reason, chemical modifications of the CD groups drastically increase the solubility [7]. Modifications of CDs with polymer chains enable the characteristic mobility even without the use of solvents. Graft

Structure/affinity studies in the bicyclo-DNA series: Synthesis and properties of oligonucleotides containing bc^en-T and iso-tricyclo-T nucleosides

• Branislav Dugovic,
• Michael Wagner and
• Christian J. Leumann

Beilstein J. Org. Chem. 2014, 10, 1840–1847, doi:10.3762/bjoc.10.194

• past to be a promising therapeutic principle [8]. There exists a multitude of chemical modifications in ASOs. Historically, the first modification was the replacement of the phosphodiester linking units in DNA by phosphorothioate groups, thus conferring higher metabolic stability to ASOs in plasma and

Multicomponent reactions in nucleoside chemistry

• Mariola Koszytkowska-Stawińska and
• Włodzimierz Buchowicz

Beilstein J. Org. Chem. 2014, 10, 1706–1732, doi:10.3762/bjoc.10.179

• . Biochemical properties of the novel nucleoside analogs are also presented (if provided by the authors). Keywords: multicomponent reaction; nucleoside analog; nucleoside antibiotics; nucleoside construction; nucleoside modification; Introduction Chemical modifications of natural ribose or 2'-deoxyribose

• interesting compounds. An intensification of studies on the structure–activity relationship of these compounds would provide valuable data on their potential applications. We hope that continued efforts in this field will result in novel nucleoside drug candidates. Selected chemical modifications of natural

Automated solid-phase peptide synthesis to obtain therapeutic peptides

• Veronika Mäde,
• Sylvia Els-Heindl and
• Annette G. Beck-Sickinger

Beilstein J. Org. Chem. 2014, 10, 1197–1212, doi:10.3762/bjoc.10.118

• their respective targets have led to tremendous progress for therapeutic applications in the last years. In order to increase the drugability of these frequently unstable and rapidly cleared molecules, chemical modifications are of great interest. Automated solid-phase peptide synthesis (SPPS) offers a

• produce these peptides in order to develop chemically engineered peptidomimetics or to uncover their distinct binding modes. Figure 4 illustrates possible strategies and Figure 5 feasible moieties for chemical modifications, which can be incorporated by semi-automated Fmoc/t-Bu-based SPPS. Amino acid

Site-selective covalent functionalization at interior carbon atoms and on the rim of circumtrindene, a C₃₆H₁₂ open geodesic polyarene

• Hee Yeon Cho,
• Ronald B. M. Ansems and
• Lawrence T. Scott

Beilstein J. Org. Chem. 2014, 10, 956–968, doi:10.3762/bjoc.10.94

• functionalization of circumtrindene Since the isolation and characterization of the first polycyclic aromatic hydrocarbons in the 1800s, a tremendous range of chemical reactions on such compounds has been developed [41][42]. Most of this chemistry involves chemical modifications on the edge carbons and has been

Intermediates in monensin biosynthesis: A late step in biosynthesis of the polyether ionophore monensin is crucial for the integrity of cation binding

• Wolfgang Hüttel,
• Jonathan B. Spencer and
• Peter F. Leadlay

Beilstein J. Org. Chem. 2014, 10, 361–368, doi:10.3762/bjoc.10.34

• surrounding the sodium ion. It has previously been shown that chemical modifications at the C-25 and/or C-26 hydroxy groups of monensin A lower both cation binding and antibiotic activity [35][36], presumably by the same mechanism. However, not all derivatives at C-26 behave in the same way: both natural and

Synthesis and characterization of novel bioactive 1,2,4-oxadiazole natural product analogs bearing the N-phenylmaleimide and N-phenylsuccinimide moieties

• Catalin V. Maftei,
• Elena Fodor,
• Peter G. Jones,
• M. Heiko Franz,
• Gerhard Kelter,
• Heiner Fiebig and
• Ion Neda

Beilstein J. Org. Chem. 2013, 9, 2202–2215, doi:10.3762/bjoc.9.259

• ][24][25][26][27]. Barrett et al. point out that the possibility of performing chemical modifications is a requirement for developing novel drugs, a strong activity is just the starting point [28]. Another moiety worth investigation is succinimide, because N-phenylsuccinimides are regarded as some of

Damage of polyesters by the atmospheric free radical oxidant NO₃^•: a product study involving model systems

• Catrin Goeschen and
• Uta Wille

Beilstein J. Org. Chem. 2013, 9, 1907–1916, doi:10.3762/bjoc.9.225

• . However, since this study is aimed at obtaining insight into the nature of the products in order to qualitatively assess how such chemical modifications might affect polymer stability under environmental conditions, exact yields are not required. It is reasonable to assume that only very few damaged sites

Cyclodextrin-based nanosponges as drug carriers

• Francesco Trotta,
• Marco Zanetti and
• Roberta Cavalli

Beilstein J. Org. Chem. 2012, 8, 2091–2099, doi:10.3762/bjoc.8.235

• low water solubility (1.85% w/v at 25 °C) and is toxic when injected intravenously. Consequently, many chemical modifications of cyclodextrins have been studied in an attempt to overcome their limitations and improve their technological characteristics. Well-structured molecules as well as random