Synthesis of novel conjugates of a saccharide, amino acids, nucleobase and the evaluation of their cell compatibility

• Dan Yuan,
• Xuewen Du,
• Junfeng Shi,
• Ning Zhou,
• Abdulgader Ahmed Baoum and
• Bing Xu

Beilstein J. Org. Chem. 2014, 10, 2406–2413, doi:10.3762/bjoc.10.250

• unique types of heteroatom aromatics, not only promote self-assembly [30], but also have the capability for DNA delivery [16]. To examine the role of the saccharide, we also designed and synthesized the respective conjugates of amino acids and nucleobase without the glucuronic moiety (5–8) for comparison

N–O Cleavage reactions of heterobicycloalkene-fused 2-isoxazolines

• Jaipal R. Nagireddy,
• Geoffrey K. Tranmer,
• Emily Carlson and
• William Tam

Beilstein J. Org. Chem. 2014, 10, 2200–2205, doi:10.3762/bjoc.10.227

• heteroatom of the bicycloalkene rather than to the nitrogen of the isoxazoline, reducing its tendency toward N–O cleavage. Furthermore, since the reaction did not proceed in the absence of either AlCl3 or nickel, coordination of both metals appears to be an essential step in the formation of 16. Under the

• optimized conditions, we suggest that initial binding of Lewis acidic aluminum to the bridge heteroatom of 10 leaves its isoxazoline nitrogen free to interact with the Raney nickel (Scheme 5, 23). The N–O bond is subsequently broken to afford 24, and it is conceivable at this stage that the added

Chiral phosphines in nucleophilic organocatalysis

• Yumei Xiao,
• Zhanhu Sun,
• Hongchao Guo and
• Ohyun Kwon

Beilstein J. Org. Chem. 2014, 10, 2089–2121, doi:10.3762/bjoc.10.218

• of carbon–carbon and carbon–heteroatom bond-forming transformations [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Many phosphine-catalyzed reactions have been developed for the syntheses of various biologically important acyclic and cyclic molecules. Asymmetric variants of these

• highly functionalized cyclopentenes that bear an array of heteroatom-substituted quaternary stereocenters [36]. From a screening of catalysts, they carefully examined the effect of substitution of the binaphthyl framework of chiral phosphines, identifying the 3,3´-diphenyl-substituted phosphepine B4 as

• 1,1-disubstituted olefins proceeded smoothly to give functionalized cyclopentenes in satisfactory yields with up to 98% ee (Scheme 3). That study extended the substrate scope of known asymmetric phosphine-catalyzed [3 + 2] annulation reactions to diverse heteroatom-substituted olefins and allenamides

Photorelease of phosphates: Mild methods for protecting phosphate derivatives

• Sanjeewa N. Senadheera,
• Abraham L. Yousef and
• Richard S. Givens

Beilstein J. Org. Chem. 2014, 10, 2038–2054, doi:10.3762/bjoc.10.212

• organic chemistry and biochemistry, but they are particularly important for mechanistic studies in biochemistry and biophysics [6][8][9][10][11]. Most PPG candidates require sufficiently high energy excited states for heterolysis of a carbon–oxygen or carbon–heteroatom bond that binds the chromophore to a

Application of cyclic phosphonamide reagents in the total synthesis of natural products and biologically active molecules

• Thilo Focken and
• Stephen Hanessian

Beilstein J. Org. Chem. 2014, 10, 1848–1877, doi:10.3762/bjoc.10.195

• phosphonamide 28e provided a diastereomer of 32 with the opposite configuration of the newly formed stereocenter. This inversion in asymmetric induction relative to non-heteroatom substituted phosphonamides such as 28a is presumably a result of a chelated intermediate that exposes the opposite face of the anion

Synthesis of new, highly luminescent bis(2,2’-bithiophen-5-yl) substituted 1,3,4-oxadiazole, 1,3,4-thiadiazole and 1,2,4-triazole

• Anastasia S. Kostyuchenko,
• Vyacheslav L.Yurpalov,
• Aleksandra Kurowska,
• Wojciech Domagala,
• Adam Pron and
• Alexander S. Fisyuk

Beilstein J. Org. Chem. 2014, 10, 1596–1602, doi:10.3762/bjoc.10.165

• completive heteroatom. Moderate to high fluorescence quantum efficiency yields are also observed, ranging from 0.59 for 18 to 0.21 for 15. Here, a clear heteroatom effect is observed, while the influence of the thiophene substituent seems negligible. The observed trend of decreasing quantum yield with

• increasing atomic number of the heteroatom of the azole unit is a clear manifestation of the heavy atom effect [35]. The proximity and availability of higher energy 3d levels in sulfur facilitates radiationless relaxation modes of the excited electron. Enhanced spin–orbit coupling opens up intersystem

A tandem Mannich addition–palladium catalyzed ring-closing route toward 4-substituted-3(2H)-furanones

• Jubi John,
• Eliza Târcoveanu,
• Peter G. Jones and
• Henning Hopf

Beilstein J. Org. Chem. 2014, 10, 1462–1470, doi:10.3762/bjoc.10.150

• economic and most importantly eco-friendly [1][2]. Conjugate addition is a very efficient tool used by synthetic chemists for the construction of carbon–carbon or carbon–heteroatom bonds [3]. Much effort has been invested to develop different variants of conjugate additions, both in catalyzed and non

• closure of the primary adduct to form the furanone. In this paper, we report our investigations that extend the reaction to heteroatom-containing electrophiles such as imines and diazo esters. Results and Discussion Following the work on nitrostyrenes, Yan et al. also reported a two-step asymmetric route

Homochiral BINOL-based macrocycles with π-electron-rich, electron-withdrawing or extended spacing units as receptors for C₆₀

• Marco Caricato,
• Silvia Díez González,
• Idoia Arandia Ariño and
• Dario Pasini

Beilstein J. Org. Chem. 2014, 10, 1308–1316, doi:10.3762/bjoc.10.132

• made chiral by substituting one of the nitrogen atoms, and the enantioselective complexation of chiral higher fullerenes (C84) has been demonstrated [22]. Complexes of C60 and C70 with large, calix-type macrocycles formed by π-electron deficient pyridine aromatic rings bridged by a nitrogen heteroatom

Synthesis of ethoxy dibenzooxaphosphorin oxides through palladium-catalyzed C(sp²)–H activation/C–O formation

• Seohyun Shin,
• Dongjin Kang,
• Woo Hyung Jeon and
• Phil Ho Lee

Beilstein J. Org. Chem. 2014, 10, 1220–1227, doi:10.3762/bjoc.10.120

• –heteroatom bond formation via C–H activation has received attention owing to the omnipresence of heterocyclic compounds in nature [8]. Recently, it has been demonstrated that the intramolecular bond formation between a heteroatom and a vicinal unreactive C–H is an efficient method for the synthesis of

Organic synthesis using photoredox catalysis

• Axel G. Griesbeck

Beilstein J. Org. Chem. 2014, 10, 1097–1098, doi:10.3762/bjoc.10.107

• -coated semiconductor nanoparticles. On the substrate side, the focus is on redox-active donor/acceptor molecules, which range from all kind of aromatic, olefinic and carbonyl-type electron acceptor compounds to heteroatom-linked electron donors. The relevance of carbon–carbon bond formation for organic

Clean and fast cross-coupling of aryl halides in one-pot

• Valerica Pandarus,
• Geneviève Gingras,
• François Béland,
• Rosaria Ciriminna and
• Mario Pagliaro

Beilstein J. Org. Chem. 2014, 10, 897–901, doi:10.3762/bjoc.10.87

• –Miyaura reaction. Results in Table 1 show that, following aqueous work-up, different unsymmetrically coupled compounds are obtained in good to excellent yields by coupling numerous different aryl bromides with different aryl halides, including heteroatom-containing aryls. In detail, entries 1 and 2 in

Integration of enabling methods for the automated flow preparation of piperazine-2-carboxamide

• Richard J. Ingham,
• Claudio Battilocchio,
• Joel M. Hawkins and
• Steven V. Ley

Beilstein J. Org. Chem. 2014, 10, 641–652, doi:10.3762/bjoc.10.56

• which demonstrated the hydration of broad classes of nitriles by passing aqueous–organic solutions through a packed bed of manganese dioxide [21], we have found that heteroaromatic nitriles possessing a β-heteroatom can also be hydrolysed using hydrous zirconia [22][23] in a similar fashion (Figure 3

Direct and indirect single electron transfer (SET)-photochemical approaches for the preparation of novel phthalimide and naphthalimide-based lariat-type crown ethers

• Dae Won Cho,
• Patrick S. Mariano and
• Ung Chan Yoon

Beilstein J. Org. Chem. 2014, 10, 514–527, doi:10.3762/bjoc.10.47

• processes (e.g., Norrish type II reaction) [38][45][46] that produce cyclic amides 5 via 4 (Scheme 2), photoirradiation of phthalimides containing thioether and/or amine chains 2 promotes more rapidly the intramolecular SET from the heteroatom donors (S and N) to the phthalimide excited states. The SET

• binding properties with a variety of cationic guests. In typical cases, carbon or nitrogen-pivot lariat crown ethers are comprised of crown ether cores and one or more heteroatom-containing side arms that are covalently bonded to carbon or nitrogen in the core. The skeletal framework and position of

• cyclization of substrates that contain electrophilic and nucleophilic centers at the opposite ends of a poly-heteroatom-containing chain. The features of these types of reactions dictate that high dilution conditions should be employed in order to maximize the cyclization to suppress the polymerization. In

Silver and gold-catalyzed multicomponent reactions

• Giorgio Abbiati and
• Elisabetta Rossi

Beilstein J. Org. Chem. 2014, 10, 481–513, doi:10.3762/bjoc.10.46

• VM process can be performed with linear, cyclic, α-branched, β-branched and tert-butylaldehydes as well as with heteroatom-containing aldehydes. Hence, COOMe, OBn and NHBoc substituents are well tolerated and afford the corresponding butenolide derivatives in moderate yields (44–56%). Moreover, the N

• “softer” chelating heteroatom (sulfur) with the late transition metal, which in turn resulted in improved enantiodifferentiation via a more organized transition state. Two more examples of enantioselective reactions involving silver catalysts have been recently reported. Both reactions involve amines

Practical synthesis of aryl-2-methyl-3-butyn-2-ols from aryl bromides via conventional and decarboxylative copper-free Sonogashira coupling reactions

• Andrea Caporale,
• Stefano Tartaggia,
• Andrea Castellin and
• Ottorino De Lucchi

Beilstein J. Org. Chem. 2014, 10, 384–393, doi:10.3762/bjoc.10.36

• coupling) and diaryl diacetylenes (sp–sp coupling) in addition to examples of carbon-heteroatom couplings have been reported in the recent literature [47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65]. The convenience in using propiolic acid as the alkyne source in the synthesis

Deoxygenative gem-difluoroolefination of carbonyl compounds with (chlorodifluoromethyl)trimethylsilane and triphenylphosphine

• Fei Wang,
• Lingchun Li,
• Chuanfa Ni and
• Jinbo Hu

Beilstein J. Org. Chem. 2014, 10, 344–351, doi:10.3762/bjoc.10.32

• , we have developed a relatively environmentally benign method to prepare TMSCF2Br, which can be used as a general carbene source for the difluoromethylenation of alkynes and alkenes and difluoromethylation of heteroatom nucleophiles [34]. In this paper, the novel preparation of TMSCF2Cl from TMSCF2Br

• heteroatom nucleophiles with TMSCF2X [31][32][33][34]. Bromo–chloro exchange reaction using AgCl. Proposed different reaction pathways of the difluorinated ylide in the presence of TMSCl and TMSBr. Plausible mechanisms for the formation of difluoromethylene triphenylphosphonium ylide from TMSCF2Cl and PPh3

Tuning the interactions between electron spins in fullerene-based triad systems

• Maria A. Lebedeva,
• Thomas W. Chamberlain,
• E. Stephen Davies,
• Bradley E. Thomas,
• Martin Schröder and
• Andrei N. Khlobystov

Beilstein J. Org. Chem. 2014, 10, 332–343, doi:10.3762/bjoc.10.31

• ; fullerene triads; spin–spin interactions; Introduction Fabricating molecular systems that are capable of storing one or more unpaired electrons is essential for the development of molecular spintronics and electron-spin-based quantum computing. Endohedral fullerenes are compounds that contain a heteroatom

Recent applications of the divinylcyclopropane–cycloheptadiene rearrangement in organic synthesis

• Sebastian Krüger and
• Tanja Gaich

Beilstein J. Org. Chem. 2014, 10, 163–193, doi:10.3762/bjoc.10.14

• overview of the new mechanistic insights concerning the title reaction is provided as well as a condensed account on the biological relevance of the topic. Heteroatom variants of this rearrangement are covered briefly. Keywords: cycloheptadiene; divinylcyclopropane rearrangement; domino reactions; natural

• corresponding cis-divinylcyclopropane (9). Calculations have been carried out for cis-divinylheterocyclopropanes including nitrogen, oxygen, sulfur and phosphorus substitution [22], as well as cis-1,2-cyclobutanes [19][23]. Earlier calculations have been carried out for mono-heteroatom substitution in the vinyl

• particular striking example propargylic alcohol 279 could be converted into bicyclic ketone 281 in good yields. Heteroatom variants The oxygen substituted versions of the DVCPR have been subject to more intense research in the covered time period than the corresponding nitrogen variants. In general there are

IBD-mediated oxidative cyclization of pyrimidinylhydrazones and concurrent Dimroth rearrangement: Synthesis of [1,2,4]triazolo[1,5-c]pyrimidine derivatives

• Caifei Tang,
• Zhiming Li and
• Quanrui Wang

Beilstein J. Org. Chem. 2013, 9, 2629–2634, doi:10.3762/bjoc.9.298

• synthesis because of their low toxicity, stability, high reactivity, and availability. Efficient formation of new carbon–heteroatom bonds as well as carbon–carbon bonds can be achieved typically under mild reaction conditions with these metal-free reagents [18][19]. For example, Salgado has described the

New developments in gold-catalyzed manipulation of inactivated alkenes

• Michel Chiarucci and
• Marco Bandini

Beilstein J. Org. Chem. 2013, 9, 2586–2614, doi:10.3762/bjoc.9.294

• toward a number of complexity-oriented transformations. In this segment, gold-catalyzed addition of carbon- and heteroatom-based nucleophiles to inactivated alkenes are widely recognized as “capricious” transformations due to alkyne and allene counterparts [1][2][3][4][5]. However, over the past few

The myxocoumarins A and B from Stigmatella aurantiaca strain MYX-030

• Tobias A. M. Gulder,
• Snežana Neff,
• Traugott Schüz,
• Tammo Winkler,
• René Gees and
• Bettina Böhlendorf

Beilstein J. Org. Chem. 2013, 9, 2579–2585, doi:10.3762/bjoc.9.293

• ). These signals were assigned to three methyl groups (14.0, 16.5, and 21.2 ppm), eight methylene units (22.6, 23.4, 29.2, 29.3, 29.4, 29.8, 31.8, and 38.3 ppm), a quaternary carbon at 46.5 ppm, a heteroatom-substituted quaternary carbon – most likely a tertiary alcohol – at 79.1 ppm, an ester-type

• functionality at 172.5 ppm, and six sp2-hybridized carbon atoms as part of an highly heteroatom-substituted aromatic system (103.2, 108.0, 118.6, 148.3, 149.2, and 157.8 ppm). The presence of the latter moiety was further corroborated by the 1H NMR spectral data: two doublets with chemical shifts at 7.43 and

• structural organization of the aromatic system was further investigated by HMBC spectroscopy. The proton at 7.43 ppm showed strong correlations with two of the heteroatom-substituted carbons at 157.8 and 148.3 ppm, the putatively alkyl substituted position at 118.6 ppm, as well as the C atom at 103.2 ppm

Direct electrophilic N-trifluoromethylthiolation of amines with trifluoromethanesulfenamide

• Sébastien Alazet,
• Kevin Ollivier and
• Thierry Billard

Beilstein J. Org. Chem. 2013, 9, 2354–2357, doi:10.3762/bjoc.9.270

• interest [10]. Compounds with this group constitute important targets for applications in pharmaceuticals and agrochemicals [4][11][12][13]. The association of a CF3 group to more than one heteroatom is rarely described in literature. In particular, there are only a few investigations regarding the

Gold(I)-catalyzed hydroarylation reaction of aryl (3-iodoprop-2-yn-1-yl) ethers: synthesis of 3-iodo-2H-chromene derivatives

• Pablo Morán-Poladura,
• Eduardo Rubio and
• José M. González

Beilstein J. Org. Chem. 2013, 9, 2120–2128, doi:10.3762/bjoc.9.249

• accomplish a reaction manifold earlier recognized in the synthesis of regioisomeric halogenated phenanthrenes, but they are using two different metals [45]. Catalytic cycloisomerization reactions of heteroatom-substituted alkynes that take place without heteroatom migration are known [46][47][48]. On this

Gold-catalyzed reaction of oxabicyclic alkenes with electron-deficient terminal alkynes to produce acrylate derivatives

• Yin-wei Sun,
• Qin Xu and
• Min Shi

Beilstein J. Org. Chem. 2013, 9, 1969–1976, doi:10.3762/bjoc.9.233

• ][45][46][47][48][49][50][51][52][53][54][55][56]. Many gold complexes have been proved to be efficient catalysts in C–C [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] bond or C–X (X = heteroatom) [49][50][51][52][53][54][55][56] bond forming reactions. Our group has a long-standing

Synthesis and antibacterial activity of monocyclic 3-carboxamide tetramic acids

• Yong-Chul Jeong and
• Mark G. Moloney

Beilstein J. Org. Chem. 2013, 9, 1899–1906, doi:10.3762/bjoc.9.224

• . The substituents of system 3 were chosen in order to probe the effect of a C(3) substituent containing a sulfur heteroatom, which we had earlier seen results in enhanced antibacterial activity compared with the oxygen counterpart [10], for two types of amide substituent and a range of C(3