Towards potential nanoparticle contrast agents: Synthesis of new functionalized PEG bisphosphonates

• Souad Kachbi-Khelfallah,
• Maelle Monteil,
• Margery Cortes-Clerget,
• Evelyne Migianu-Griffoni,
• Jean-Luc Pirat,
• Olivier Gager,
• Julia Deschamp and
• Marc Lecouvey

Beilstein J. Org. Chem. 2016, 12, 1366–1371, doi:10.3762/bjoc.12.130

• amino functional groups. The azido products will allow us to perform click chemistry to introduce various functionalities. Moreover, the amino derivatives will be easily obtained by reducing the azido group. As previously mentioned, the first step was a selective mono-activation of PEG using para

Application of Cu(I)-catalyzed azide–alkyne cycloaddition for the design and synthesis of sequence specific probes targeting double-stranded DNA

• Svetlana V. Vasilyeva,
• Vyacheslav V. Filichev and
• Alexandre S. Boutorine

Beilstein J. Org. Chem. 2016, 12, 1348–1360, doi:10.3762/bjoc.12.128

• helices by TFO-MGB conjugates was evaluated by gel-shift experiments. The presence of MGB in these conjugates did not affect the binding parameters (affinity and triplex stability) of the parent TFOs. Keywords: binding affinity; click chemistry; Cu(I)-catalyzed azide–alkyne cycloaddition; pyrrole

• of 1,2,3-triazoles can connect several components in one molecule [25][26]. CuAAC belongs to the class of chemical processes called “click-chemistry” and it is also a biorthogonal reaction because functional groups of natural biopolymers are not affected and do not participate in chemical

• . demonstrated the fluorescent labeling of proteins directly in living cells by copper-free "click chemistry" [29]. Alkyne or azide groups can be inserted into both TFO and MGB using enzymatic or chemical methods during matrix or solid-phase synthesis [2][30][31] or post-synthetically using described conjugation

Stimuli-responsive HBPS-g-PDMAEMA and its application as nanocarrier in loading hydrophobic molecules

• Yongsheng Chen,
• Li Wang,
• Haojie Yu,
• Zain-Ul-Abdin,
• Ruoli Sun,
• Guanghui Jing,
• Rongbai Tong and
• Zheng Deng

Beilstein J. Org. Chem. 2016, 12, 939–949, doi:10.3762/bjoc.12.92

• hyperbranched polystyrene. Chen reported a star-like polymer HBPS-g-PNIPAM in which HBPS was prepared by click chemistry to load small hydrophobic molecules [25]. However, its preparation needs specially designed monomers, the preparation of which is tedious and time-comsuming. Hyperbranched polystyrene (HBPS

Superstructures with cyclodextrins: chemistry and applications III

• Gerhard Wenz and
• Eric Monflier

Beilstein J. Org. Chem. 2016, 12, 937–938, doi:10.3762/bjoc.12.91

• has been achieved in the synthesis of CD polyrotaxanes. The one-pot and one-step polyrotaxane synthesis of β-CDs was performed in aqueous solution by employing a click reaction [7] as well as by radical copolymerization [8]. Slide-ring gels, synthesized by the group of K. Ito through the crosslinking

From steroids to aqueous supramolecular chemistry: an autobiographical career review

• Bruce C. Gibb

Beilstein J. Org. Chem. 2016, 12, 684–701, doi:10.3762/bjoc.12.69

• using “Click” chemistry [37]. Forming stable complexes for a broad range of guests, the capsules formed by octa-acid are ideal nano-scale (yocto-liter) reaction vessels. Our first foray into this topic relied on collaboration with Vaidhyanathan Ramamurthy, and examined a wide range of photophysics, and

Creating molecular macrocycles for anion recognition

• Amar H. Flood

Beilstein J. Org. Chem. 2016, 12, 611–627, doi:10.3762/bjoc.12.60

• activity surrounding 1,2,3-triazoles made using click chemistry; and the same triazoles are responsible for anion capture. Mistakes made and lessons learnt in anion recognition provide deeper understanding that, together with theory, now provides for computer-aided receptor design. The lessons are acted

• philosophy for synthetic design that was derived from Roald Hoffmann’s idea of chemistry being “the same and not the same” [9]. At around this time (2006), click chemistry [10] (Figure 3) had caught my attention for its prevalence but I did not know why it was being used so much. All I could venture was that

• it was an old reaction, the Huisgen cycloaddition, made good (regioselective) with the aid of copper catalysis. Taking that idea on face value, I reasoned that click chemistry was a new and extremely effective way to make 1,2,3-triazoles. It is not often that either new or newly refined reactions

Enabling technologies and green processes in cyclodextrin chemistry

• Giancarlo Cravotto,
• Marina Caporaso,
• Laszlo Jicsinszky and
• Katia Martina

Beilstein J. Org. Chem. 2016, 12, 278–294, doi:10.3762/bjoc.12.30

• friendly technique that is well suited to the selective chemical modification of CDs from native α-, β- and γ-CD. The use of this method in heterogeneous phase reactions, such as reductions and “click reactions” [14], is well known, as is its use in full CD derivatization in combination with MW irradiation

• -assisted click cluster synthesis. An example of the MW-promoted ‘cooperative’ click reaction of azido-CDs has recently been reported and offers useful synthetic insights into a specific labelling strategy [54]. The aforementioned reaction afforded a new series of antimicrobial γ-CD derivatives that

• strongly disrupt bacterial membranes, and a series of persubstituted γ-CD derivatives bearing polyamino groups (77% yield) [55]. MW-promoted Cu-catalyzed click reaction for the preparation of second generation CD derivatives and hybrid structures The MW-promoted CuAAC between CD monoazides and acetylenic

Recent advances in metathesis-derived polymers containing transition metals in the side chain

• Ileana Dragutan,
• Valerian Dragutan,
• Bogdan C. Simionescu,
• Albert Demonceau and
• Helmut Fischer

Beilstein J. Org. Chem. 2015, 11, 2747–2762, doi:10.3762/bjoc.11.296

• triazolyl unit was first attached to the η4-cyclopentadiene CpCo(I) complex by click reaction of the corresponding alkyne precursor and then the triazolyl-Co scaffold was incorporated into the norbornene monomer 9 by conventional esterification. It is important to note that the cyclopentadienyl-cobalt-1,3

• and tetraethylene glycol groups. Synthesis of redox-robust triazolylbiferrocenyl polymers 4. Synthesis of cobaltocenium-containing polymers by ROMP. Cobaltocenium-appending copolymers by the ROMP approach (X = PF6, Y = BPh4 or Cl). Cobalt-containing polymers by click and ROMP approach. Synthesis of

Selectively fluorinated cyclohexane building blocks: Derivatives of carbonylated all-cis-3-phenyl-1,2,4,5-tetrafluorocyclohexane

• Mohammed Salah Ayoup,
• David B. Cordes,
• Alexandra M. Z. Slawin and
• David O'Hagan

Beilstein J. Org. Chem. 2015, 11, 2671–2676, doi:10.3762/bjoc.11.287

• illustrated in Scheme 4 [17]. Reduction of benzyl azide 21 to generate amine 27 as its hydrochloride salt was achieved by a Staudinger reduction in good yield [18]. Azide 21 was also amenable to a ‘click’ reaction, in this case with the acetylenic protected amino acid 24 [19]. This gave the 1,2,3-triazol

Exploring architectures displaying multimeric presentations of a trihydroxypiperidine iminosugar

• Camilla Matassini,
• Stefania Mirabella,
• Andrea Goti,
• Inmaculada Robina,
• Antonio J. Moreno-Vargas and
• Francesca Cardona

Beilstein J. Org. Chem. 2015, 11, 2631–2640, doi:10.3762/bjoc.11.282

• , Universidad de Sevilla, c/ Prof. García González 1, E-41012, Sevilla, Spain 10.3762/bjoc.11.282 Abstract The synthesis of new multivalent architectures based on a trihydroxypiperidine α-fucosidase inhibitor is reported herein. Tetravalent and nonavalent dendrimers were obtained by means of the click

• ). The low yield observed for the click reaction of the deprotected azido derivative 10 can be ascribed to the tricky purification of 11 that was recovered from silica gel only by eluting with 33% NH4OH due to its high basicity (see Experimental section). For this reason we decided to change the strategy

• by performing the click reaction on the protected azido derivative 4, analogously to what reported with the tetravalent scaffold 5. Reaction of 4 (9 equiv) with the nonavalent alkyne scaffold 6 gave compound 12 in excellent 92% yield (Scheme 5). After treatment in acidic methanol at room temperature

Synthesis of bi- and bis-1,2,3-triazoles by copper-catalyzed Huisgen cycloaddition: A family of valuable products by click chemistry

• Zhan-Jiang Zheng,
• Ding Wang,
• Zheng Xu and
• Li-Wen Xu

Beilstein J. Org. Chem. 2015, 11, 2557–2576, doi:10.3762/bjoc.11.276

• Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, P. R. China 10.3762/bjoc.11.276 Abstract The Cu(I)-catalyzed azide-alkyne cycloaddition reaction, also known as click chemistry, has become a useful tool for the facile formation of 1,2,3-triazoles

• . Specifically, the utility of this reaction has been demonstrated by the synthesis of structurally diverse bi- and bis-1,2,3-triazoles. The present review focuses on the synthesis of such bi- and bistriazoles and the importance of using copper-promoted click chemistry (CuAAC) for such transformations. In

• addition, the application of bitriazoles and the related CuAAAC reaction in different fields, including medicinal chemistry, coordination chemistry, biochemistry, and supramolecular chemistry, have been highlighted. Keywords: bistriazoles; click chemistry; cycloaddition; homogeneous catalysis; oxidative

Copper catalysis in organic synthesis

• Sherry R. Chemler

Beilstein J. Org. Chem. 2015, 11, 2252–2253, doi:10.3762/bjoc.11.244

• . Some of the most highly cited papers of all time on this topic are reviews on conjugate addition, cross-coupling, and [3 + 2] “Click” reaction applied to bioconjugation. The growth in copper-catalyzed organic reactions may be driven by a couple of factors. First, copper chemistry is incredibly diverse

• field of copper-catalysis from 7 countries make up this Thematic Series, “Copper catalysis in organic synthesis”. Contributions include authoritative reviews on the latest developments in copper-catalyzed Click applications, C–N cross-coupling, C–H functionalization, trifluoromethylations, asymmetric

• synthesis, amide bond formation and photochemical Click reaction development. I am grateful to the contributors and the reviewers who participated in the production of this Thematic Series. It is clear from the impact copper catalysis has had on organic synthesis that copper should be considered a first

Easy access to heterobimetallic complexes for medical imaging applications via microwave-enhanced cycloaddition

• Nicolas Desbois,
• Sandrine Pacquelet,
• Adrien Dubois,
• Clément Michelin and
• Claude P. Gros

Beilstein J. Org. Chem. 2015, 11, 2202–2208, doi:10.3762/bjoc.11.239

• Nicolas Desbois Sandrine Pacquelet Adrien Dubois Clement Michelin Claude P. Gros Université de Bourgogne Franche-Comté, ICMUB (UMR CNRS 6302), 9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex, France 10.3762/bjoc.11.239 Abstract The Cu(I)-catalysed Huisgen cycloaddition, known as “click

• are promising contrast agents (CA) in MRI. Keywords: click chemistry; corrole; DOTA; microwave; NOTA; porphyrin; Introduction Magnetic resonance imaging (MRI), positron emission tomography (PET) or single photon emission computed tomography (SPECT) are actually the most commonly used imaging

• and alkyne derivatives to further interconnect by microwave-assisted click reaction. Azidocorroles/porphyrins Azidocorrole 1 [9] was obtained by the condensation of the corresponding meso-mesityl-substituted dipyrromethane with 4-azidobenzaldehyde in the presence of a catalytic amount of

Effective ascorbate-free and photolatent click reactions in water using a photoreducible copper(II)-ethylenediamine precatalyst

• Redouane Beniazza,
• Natalia Bayo,
• Florian Molton,
• Carole Duboc,
• Stéphane Massip,
• Nathan McClenaghan,
• Dominique Lastécouères and
• Jean-Marc Vincent

Beilstein J. Org. Chem. 2015, 11, 1950–1959, doi:10.3762/bjoc.11.211

• , F-38000 Grenoble, France Univ. Bordeaux, IECB, UMS 3033/US 001, 2 rue Escarpit, 33607 Pessac, France CNRS, IECB, UMS 3033, 33600 Pessac, France INSERM, IECB, US 001, 33600 Pessac, France 10.3762/bjoc.11.211 Abstract The search for copper catalysts able to perform effectively click reactions in

• photoreduced in water when alkynes were present in solution. The catalytic activity of 1 for click reactions involving a range of water-soluble alkynes and azides, in particular saccharides, was tested under various illumination conditions. Complex 1 was found to exhibit a photolatent character, the

• photogenerated copper(I) being very reactive. On irradiating aqueous reaction mixtures containing 1 mol % of 1 at 365 nm (TLC lamp) for 1 h, click reactions were shown to proceed to full conversion. Keywords: benzophenone photosensitizer; bioconjugation; click chemistry; copper; photoreduction; Introduction

Synthesis and spectroscopic properties of β-triazoloporphyrin–xanthone dyads

• Dileep Kumar Singh and
• Mahendra Nath

Beilstein J. Org. Chem. 2015, 11, 1434–1440, doi:10.3762/bjoc.11.155

• ) were synthesized in good yields by the “click reaction” of 3,6-diethynylxanthen-9-one (11) with copper and zinc azidoporphyrins, respectively. Further, the free-base diporphyrins 12b and 13b were obtained in 81% and 84% yields, respectively after the treatment of 12a with conc. H2SO4 at 0 °C and 13a

• -diethynylxanthen-9-one. In addition, a new series of various β-triazole-linked porphyrin–xanthone conjugates and xanthone-bridged triazoloporphyrin dyads were synthesized through click chemistry in moderate to good yields. The preliminary photophysical evaluation of these π-conjugated molecules revealed a

Synthesis of alpha-tetrasubstituted triazoles by copper-catalyzed silyl deprotection/azide cycloaddition

• Zachary L. Palchak,
• Paula T. Nguyen and
• Catharine H. Larsen

Beilstein J. Org. Chem. 2015, 11, 1425–1433, doi:10.3762/bjoc.11.154

• -deprotection with azide–alkyne cycloaddition, producing hindered triazoles in 6 hours. This tandem reaction was optimal with a copper(II) triflate and sodium ascorbate (NaAsc) as a mild reductant. The outcome that copper(II) triflate provides the highest yields for the one-pot deprotection/click reaction was

• (blue). KA2 coupling followed by tandem silyl deprotection and triazole formation. Silyl deprotection/click conditions applied to tert-butylacetylene. An identical yield is observed without TBAF. High overall yield of 1,2,3-triazole fully-substituted at the 4-position. Optimization of silyl deprotection

Synthesis of γ-hydroxypropyl P-chirogenic (±)-phosphorus oxide derivatives by regioselective ring-opening of oxaphospholane 2-oxide precursors

• Iris Binyamin,
• Shoval Meidan-Shani and
• Nissan Ashkenazi

Beilstein J. Org. Chem. 2015, 11, 1332–1339, doi:10.3762/bjoc.11.143

• ., after the "click" reaction) [61]. Conclusion In this work, we demonstrated the generality and the versatility of oxaphospholanes such as 4 and 5 to serve as precursors for the synthesis of γ-hydroxypropyl (±)-phosphinates and phosphine oxides, respectively, using Grignard reactions. Noteworthy is the

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

• (Scheme 51). [3 + 2] Cycloaddition (1,3-dipolar cycloaddition/click reaction): In 2010, Raghunathan and co-workers [185] have synthesized a C2-symmetric triazolophane by a copper(I)-catalyzed azide-alkyne cycloaddition, involving a click reaction. The dipropargyl fluorenyl derivative 299 was prepared from

• 308 in the presence of CuSO4 and sodium ascorbate in acetonitrile/water to deliver the desired cyclophane derivative 309 (56%, Scheme 53). Similarly, a novel BINOL-based cyclophane 310 has been synthesized via click chemistry by incorporating two triazole moieties in the macrocycle [187]. Li and co

Synthesis of novel N-cyclopentenyl-lactams using the Aubé reaction

• Madhuri V. Shinde,
• Rohini S. Ople,
• Ekta Sangtani,
• Rajesh Gonnade and
• D. Srinivasa Reddy

Beilstein J. Org. Chem. 2015, 11, 1060–1067, doi:10.3762/bjoc.11.119

• literature and the data were compared with that reported [34]. The structure of the minor diastereomer (±)-4’ was assigned based on 2D NMR correlations. Secondly, the azido alcohol (±)-3 was subjected to a click reaction with phenylacetylene under standard conditions and the resulting two compounds, (±)-5

Quarternization of 3-azido-1-propyne oligomers obtained by copper(I)-catalyzed azide–alkyne cycloaddition polymerization

• Shun Nakano,
• Akihito Hashidzume and
• Takahiro Sato

Beilstein J. Org. Chem. 2015, 11, 1037–1042, doi:10.3762/bjoc.11.116

• alkynes with a copper(I) catalyst under mild conditions even in the presence of various functional groups [1][2][3]. CuAAC is thus the most important reaction in “click chemistry” [4][5][6][7]. A number of studies have been published on CuAAC, which is applied in a wide range of fields from bio-related

Carboxylated dithiafulvenes and tetrathiafulvalene vinylogues: synthesis, electronic properties, and complexation with zinc ions

• Yunfei Wang and
• Yuming Zhao

Beilstein J. Org. Chem. 2015, 11, 957–965, doi:10.3762/bjoc.11.107

• and Cu-catalysed alkyne–azide cycloaddition (i.e., click) reactions [22][23][24][25][26]. In this work, we continued to explore the class of carboxylated diphenyl-TTFVs, in view of the synthetic versatility of the carboxyl group towards various commonly used linkage groups (e.g., amides, esters). The

DNA display of glycoconjugates to emulate oligomeric interactions of glycans

• Alexandre Novoa and
• Nicolas Winssinger

Beilstein J. Org. Chem. 2015, 11, 707–719, doi:10.3762/bjoc.11.81

• alkyne by oxidative amidation using carbon tetrachloride with propargylamine. The microwave-assisted click-conjugation was performed on a solid phase upon completion of the DNA synthesis (Scheme 4). Lönnberg and co-workers prepared a thymidine modified at the 4’-position with an azidomethyl group to

Synthesis of carbohydrate-scaffolded thymine glycoconjugates to organize multivalency

• Anna K. Ciuk and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2015, 11, 668–674, doi:10.3762/bjoc.11.75

• )-catalyzed click reaction [21][22]. Before, the acid-labile isopropylidene protecting group was removed using 10% TFA in dichloromethane leading to mannoside 4, and then the azide function in 4 was converted in a Staudinger reduction [23] with simultaneous Boc-protection giving rise to mannoside 5 in high

• for eventual immobilisation of the final thymine glycoconjugate on a surface or for conjugation to another multivalent compound. For the click reaction of 5 with the thymine derivative 6, copper sulfate and sodium ascorbate were used. The conjugation product 7 was obtained in 71% yield and showed good

• (Scheme 2). Staudinger reduction of the azide group and Boc-protection in the same pot gave 9 and subsequent click reaction with the thymine derivative 6 the isopropylidene-protected dimeric thymine glycoconjugate 10 in good yield. This could be alkylated employing the bromoethyl mannoside 11 [11] in an

Synthesis of multivalent carbohydrate mimetics with aminopolyol end groups and their evaluation as L-selectin inhibitors

• Joana Salta,
• Jens Dernedde and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2015, 11, 638–646, doi:10.3762/bjoc.11.72

• . Unfortunately, only a few of our prepared compounds were sufficiently soluble in water to be suitable for the SPR test. However, a series of other multivalent conjugates was synthesized by using click chemistry with the azide derived from aminopyran 1 and results will be published in due time [40]. Conclusion

Synthesis of a hexasaccharide partial sequence of hyaluronan for click chemistry and more

• Marina Bantzi,
• Stephan Rigol and
• Athanassios Giannis

Beilstein J. Org. Chem. 2015, 11, 604–607, doi:10.3762/bjoc.11.67

• Abstract In the present work, the synthesis of a hexasaccharide partial sequence of hyaluronan equipped with a terminal azido moiety is reported. This hexasaccharide can be used for the attachment on surfaces by means of click chemistry and after suitable deprotection for biophysical studies. Keywords

• : azide; click chemistry; extracellular matrix; hexasaccharide; hyaluronan; multivalency; Introduction Much effort has been exerted during the last years to refine current knowledge about the biology of the extracellular matrix (ECM) [1]. While in the past, it was only regarded as a “space filler” among

• , allowing it to be used for surface modification via click chemistry. After suitable deprotection it can be used for biophysical studies by interaction with an alkyne group of suitably prepared proteins or proteoglycans giving the opportunity to gain deeper insights into ECM processes. Eventually, this