Design, synthesis and photochemical properties of the first examples of iminosugar clusters based on fluorescent cores

• Mathieu L. Lepage,
• Antoine Mirloup,
• Manon Ripoll,
• Fabien Stauffert,
• Anne Bodlenner,
• Raymond Ziessel and
• Philippe Compain

Beilstein J. Org. Chem. 2015, 11, 659–667, doi:10.3762/bjoc.11.74

• influence of both triazole rings. The second transition at 386 nm is assigned in light of previous studies to the S0→S2 of the BODIPY subunit [39][65][66][67]. The triazole rings absorb below 250 nm for the π–π* transition [68]. Excitation at 510 nm affords a relatively intense emission with a quantum yield

Synthesis and surface grafting of a β-cyclodextrin dimer facilitating cooperative inclusion of 2,6-ANS

• Lars W. Städe,
• Thorbjørn T. Nielsen,
• Laurent Duroux,
• Reinhard Wimmer,
• Kyoko Shimizu and
• Kim L. Larsen

Beilstein J. Org. Chem. 2015, 11, 514–523, doi:10.3762/bjoc.11.58

• −alkyne cycloaddition (CuAAC)) is very attractive [10][11]. CuAAC is known to be selective, proceed fast and produce a high yield under mild conditions. Further, the formed triazole is stable against oxidation, reduction and hydrolysis [10]. Concerning the design of β-CD dimers, it was recently

• addition, minor fractions corresponding to the triazole-β-CD monomer and β-CD trimer were observed (not shown). In the present context, the occurrence of the monomeric form is of greatest concern; however, from the NMR spectra (Supporting Information File 1) it is evident that the monomer fraction is

• -CD H-3. The fact that the cross peaks for H-5 seem to be the strongest could suggest that the guest molecule enters the β-CD cavity from the narrow rim. However, the linker atom, i.e., the CH2 group between the triazole ring and the nitrogen atom connecting the two monomeric subunits, exhibits cross

3-Glucosylated 5-amino-1,2,4-oxadiazoles: synthesis and evaluation as glycogen phosphorylase inhibitors

• Marion Donnier-Maréchal,
• David Goyard,
• Vincent Folliard,
• Tibor Docsa,
• Pal Gergely,
• Jean-Pierre Praly and
• Sébastien Vidal

Beilstein J. Org. Chem. 2015, 11, 499–503, doi:10.3762/bjoc.11.56

• around the triazole moiety was also reported [18][19]. The isomeric 1,2,4-triazole E was recently identified as a sub-micromolar GP inhibitor [20][21] and highlights the influence of the aromatic moiety used in these studies. The influence of the heterocyclic moiety was also clearly demonstrated in a

The reactions of 2-ethoxymethylidene-3-oxo esters and their analogues with 5-aminotetrazole as a way to novel azaheterocycles

• Marina V. Goryaeva,
• Yanina V. Burgart,
• Marina A. Ezhikova,
• Mikhail I. Kodess and
• Viktor I. Saloutin

Beilstein J. Org. Chem. 2015, 11, 385–391, doi:10.3762/bjoc.11.44

• preparation of compound 11 in the reaction of ester 1f with 5-AT was unexpected, because it is known that ester 1f interacts with 3-amino-1,2,4-triazole in refluxing ethanol [8] and with substituted 5-amino-1,2,4-triazoles in acetic acid [34] to afford triazolo[1,5-a]pyrimidines. However, we did not observe

C-5’-Triazolyl-2’-oxa-3’-aza-4’a-carbanucleosides: Synthesis and biological evaluation

• Roberto Romeo,
• Caterina Carnovale,
• Salvatore V. Giofrè,
• Maria A. Chiacchio,
• Adriana Garozzo,
• Emanuele Amata,
• Giovanni Romeo and
• Ugo Chiacchio

Beilstein J. Org. Chem. 2015, 11, 328–334, doi:10.3762/bjoc.11.38

• , University of Catania, Via A. Doria 6, 95125-Catania, Italy Dipartimento di Scienze Bio-Mediche, University of Catania,Via Androne 81, 95124 Catania, Italy 10.3762/bjoc.11.38 Abstract A novel series of 2’-oxa-3’-aza-4’a-carbanucleosides, featured with a triazole linker at the 5’-position, has been developed

• can interact with intracellular targets to induce cytotoxicity [28][29][30][31][32]. Several functionalities have been inserted as linkers on the 2’-oxa-3’-aza-4’a-carbanucleoside skeleton in order to confer novel mechanisms of action for nucleoside mimics: in this context, the 1,2,3-triazole unit

• , the 1,2,3-triazole motif is exceedingly stable to basic or acidic hydrolysis and interacts strongly with biological targets through hydrogen bonding to nitrogen atoms as well as through dipole–dipole and π-stacking interactions [39]. Recently, a synthetic approach towards 3-hydroxymethyl-5-(1H-1,2,3

Formation of nanoparticles by cooperative inclusion between (S)-camptothecin-modified dextrans and β-cyclodextrin polymers

• Thorbjørn Terndrup Nielsen,
• Catherine Amiel,
• Laurent Duroux,
• Kim Lambertsen Larsen,
• Lars Wagner Städe,
• Reinhard Wimmer and
• Véronique Wintgens

Beilstein J. Org. Chem. 2015, 11, 147–154, doi:10.3762/bjoc.11.14

• the characteristic triazole signal at 7.99 ppm (H) and 126 ppm (C) was found by NMR spectroscopy. The degree of substitution (DS) was calculated from integration of the triazole signal compared to the integral of the anomeric signals of the glucose units of dextran at 4.68 ppm. Four CPT-dextrans from

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• 6 to form 7) [42], benzoxazole (acetoxylation of 8 to form 9) [43], benzimidazole (alkoxylation of 10 to form 11) [44], and triazole (acyloxylation of 12 to form 13 [45], alkoxylation of 14 to form 15 [46]) moieties were also used as directing groups for the ortho-acyloxylation and alkoxylation of

Articulated rods – a novel class of molecular rods based on oligospiroketals (OSK)

• Pablo Wessig,
• Roswitha Merkel and
• Peter Müller

Beilstein J. Org. Chem. 2015, 11, 74–84, doi:10.3762/bjoc.11.11

• defined a 1,2,3-triazole containing linkage between two piperidine rings as the flexible joint F, which should be easily accessible by copper-catalyzed cycloaddition between an azide G and a terminal alkyne H (CuAAC, “Click” reaction) [16]. Primary alcohols I serve as “protected” azides accessible by

• linked by a flexible joint. The deciding feature of ARs is the equilibrium between two leading conformations: a straight (STR) and a folded (FOL) species. The joint contains a 1,2,3-triazole moiety and the synthesis was carried out by copper catalyzed alkyne/azide cycloaddition (CuAAC). To obtain ARs

NAA-modified DNA oligonucleotides with zwitterionic backbones: stereoselective synthesis of A–T phosphoramidite building blocks

• Boris Schmidtgall,
• Claudia Höbartner and
• Christian Ducho

Beilstein J. Org. Chem. 2015, 11, 50–60, doi:10.3762/bjoc.11.8

• [8]. For the selective replacement of some phosphate linkages in otherwise native oligonucleotide structures, e.g., amide [13][14][15][16][17][18][19][20], triazole [21][22], phosphoramidate [23] and phosphate triester [24] moieties were reported alongside a considerable number of other modifications

Conjugates of methylated cyclodextrin derivatives and hydroxyethyl starch (HES): Synthesis, cytotoxicity and inclusion of anaesthetic actives

• Lisa Markenstein,
• Antje Appelt-Menzel,
• Marco Metzger and
• Gerhard Wenz

Beilstein J. Org. Chem. 2014, 10, 3087–3096, doi:10.3762/bjoc.10.325

• the 1H NMR signal H-12 at 4.26 pm were converted to triazole groups (1H NMR signal H-14 at 8.03 ppm), shown in Figure 2c. The corresponding IR spectra (Figure 5s, Supporting Information File 2) revealed that the excess of azido-CD had been completely removed by the ultrafiltration step since the band

Synthesis of divalent ligands of β-thio- and β-N-galactopyranosides and related lactosides and their evaluation as substrates and inhibitors of Trypanosoma cruzi trans-sialidase

• María Emilia Cano,
• Rosalía Agusti,
• Alejandro J. Cagnoni,
• María Florencia Tesoriero,
• José Kovensky,
• María Laura Uhrig and
• Rosa M. de Lederkremer

Beilstein J. Org. Chem. 2014, 10, 3073–3086, doi:10.3762/bjoc.10.324

• the bioavailability in vivo [31]. Triazole-substituted β-galactopyranosides and triazole-sialyl mimetics have been synthesized by click chemistry and their inhibitory activity on the hydrolysis of 2’-(4-methylumbelliferyl)-β-D-N-acetylneuraminic acid by TcTS and trypanocidal activity were evaluated

• (Scheme 2A). The 1H NMR spectra showed the diagnostic signals corresponding to the aromatic protons of the triazole ring (≈7.65 ppm), as well as the anomeric signals. For compound 10, the H-1 of the βNGal appeared at 5.22 ppm (J ≈ 9.1 Hz) and the H-1 of the αGlc at 4.92 ppm (J = 3.6 Hz). In the case of 12

• , an additional anomeric signal corresponding to the terminal βGal residue was observed at 4.46 ppm (J = 7.9 Hz). Triazole carbon signals appeared at ca. 145.0 and 124.0 ppm in the 13C spectrum and anomeric carbons of the αGlc (96.8 ppm) scaffold, and the N-linked residue (78.5 ppm for the βNGal of 10

Sequential decarboxylative azide–alkyne cycloaddition and dehydrogenative coupling reactions: one-pot synthesis of polycyclic fused triazoles

• Kuppusamy Bharathimohan,
• Thanasekaran Ponpandian,
• A. Jafar Ahamed and
• Nattamai Bhuvanesh

Beilstein J. Org. Chem. 2014, 10, 3031–3037, doi:10.3762/bjoc.10.321

• describe a one-pot protocol for the synthesis of a novel series of polycyclic triazole derivatives. Transition metal-catalyzed decarboxylative CuAAC and dehydrogenative cross coupling reactions are combined in a single flask and achieved good yields of the respective triazoles (up to 97% yield). This

• ], whereas only limited reports are available for intramolecular sp2 C–H/C–H coupling reactions [34][35][36][37][38]. Compounds containing a fused triazole skeleton show remarkable biologically activities [39] and new strategies to prepare this class of molecules are highly warranted. Several methodologies

• ∙5H2O (Cu2+ used for decarboxylative CuAAC) at 120 °C for 12 h. It failed to undergo the oxidative dehydrogenative coupling reaction and the triazole derivative 3a was isolated in 79–82% yield (Table 1, entries 1–1b). A similar reaction sequence was performed with different copper salts such as CuCl2

The unexpected influence of aryl substituents in N-aryl-3-oxobutanamides on the behavior of their multicomponent reactions with 5-amino-3-methylisoxazole and salicylaldehyde

• Volodymyr V. Tkachenko,
• Elena A. Muravyova,
• Sergey M. Desenko,
• Oleg V. Shishkin,
• Svetlana V. Shishkina,
• Dmytro O. Sysoiev,
• Thomas J. J. Müller and
• Valentin A. Chebanov

Beilstein J. Org. Chem. 2014, 10, 3019–3030, doi:10.3762/bjoc.10.320

• -aminotetrazole [9], 5-aminopyrazoles [11], and 5-amino-1,2,3-triazole [12] have previously been investigated. In some cases when the reaction could proceed in two alternative pathways the conditions enabling to control the interaction direction were determined, which made it possible to obtain the desired

• derivatives from salicylaldehyde, various dicarbonyl compounds, and urea (thiourea) using PdO as a catalyst (Scheme 2). Heterocyclizations involving both, salicylaldehyde and aminoazoles, are intriguing as well. Thus, for example in the course of the study on the application of 3-amino-1,2,4-triazole and

Synthesis and characterization of a new photoinduced switchable β-cyclodextrin dimer

• Florian Hamon,
• Claire Blaszkiewicz,
• Marie Buchotte,
• Estelle Banaszak-Léonard,
• Hervé Bricout,
• Sébastien Tilloy,
• Eric Monflier,
• Christine Cézard,
• Laurent Bouteiller,
• Christophe Len and
• Florence Djedaini-Pilard

Beilstein J. Org. Chem. 2014, 10, 2874–2885, doi:10.3762/bjoc.10.304

• to the guest molecules [9][10]. These cyclodextrins linked by ester [11], thioether [12][13][14][15][16], urea [17][18][19], or triazole [20] moieties have been previously described. In addition, aromatic azobenzenes are excellent candidates as molecular switch linkers as they have two forms, namely

• ]. As an exception, Vargas et al. [29] described the synthesis of 1,2,3-triazole-linked azobenzene-cyclodextrin derivatives producing rather good yields but the photoisomerization and inclusion complex properties were not investigated. Here, we report an efficient preparation of a new bis-β-CD with

Gold(I)-catalysed synthesis of a furan analogue of thiamine pyrophosphate

• Amjid Iqbal,
• El-Habib Sahraoui and
• Finian J. Leeper

Beilstein J. Org. Chem. 2014, 10, 2580–2585, doi:10.3762/bjoc.10.270

• . Two triazole analogues 3 (Ki = 20 pM) and 4 (Ki = 30 pM against ZmPDC) were synthesised in just four synthetic steps [12]. However, there is no possibility of attaching a substituent at the 2-position of the triazole to mimic enzymic reaction intermediates. Another analogue of ThDP 5 with a benzene

• two-stage inhibition for PDC was reported by Mann et al. for the benzene-based ThDP analogue 5 [10] and the same effect was also observed by Erixon et al. using triazole analogues 3 and 4 [37] and also with a thiazolone analogue by Kluger et al. [38]. It may be due to a slow conformational change

• value of furan analogue 17 is 0.35 × (8.5/91.5) × (1/1000) µM = 32.5 pM. This Ki value is more than 10,000-fold lower than the KD value for ThDP and is in the same range as previously reported for triazole analogues of ThDP (30 and 20 pM) [12][37]. However, the furan analogue of ThDP has the advantage

A small azide-modified thiazole-based reporter molecule for fluorescence and mass spectrometric detection

• Stefanie Wolfram,
• Hendryk Würfel,
• Stefanie H. Habenicht,
• Christine Lembke,
• Phillipp Richter,
• Eckhard Birckner,
• Rainer Beckert and
• Georg Pohnert

Beilstein J. Org. Chem. 2014, 10, 2470–2479, doi:10.3762/bjoc.10.258

• bioactive metabolites and selective labeling of proteins and other biomacromolecules. A common structural motif for such probes consists of a reporter that can be attached by copper(I)-catalyzed 1,2,3-triazole formation between terminal alkynes and azides to a reactive headgroup. Here we introduce the

End group functionalization of poly(ethylene glycol) with phenolphthalein: towards star-shaped polymers based on supramolecular interactions

• Carolin Fleischmann,
• Hendrik Wöhlk and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 2263–2269, doi:10.3762/bjoc.10.235

• ) was then reacted with PP-N3 in a 1,3-diploar cycloaddition, which gave the desired phenolphthalein-functionalized mPEG-PP (see Scheme 2). Since the reaction was carried out in absence of copper(I) salts, a mixture of the 1,4- and 1,5-substituted triazole regioisomers was obtained. The host component

• moieties serving as the dipolarophil in a subsequent treatment with β-cyclodextrin azide. Thereby, a dipentaerythritol derivative carrying six cyclodextrins (DPE-CD) that are covalently attached through triazole rings was obtained. Mixing of mPEG-PP and DPE-CD resulted in the formation of stable complexes

Derivatives of the triaminoguanidinium ion, 3. Multiple N-functionalization of the triaminoguanidinium ion with isocyanates and isothiocyanates

• Jan Szabo,
• Kerstin Karger,
• Nicolas Bucher and
• Gerhard Maas

Beilstein J. Org. Chem. 2014, 10, 2255–2262, doi:10.3762/bjoc.10.234

• triaminoguanidinium salts underwent a threefold carbamoylation with aryl isocyanates to furnish 1,2,3-tris(ureido)guanidinium salts, while p-toluenesulfonyl isocyanate led only to a mono-ureido guanidinium salt. With aryl isothiocyanates, 3-hydrazino-1H-1,2,4-triazole-5(4H)-thione derivatives were obtained. Compounds

• 7a and 8 show interesting solid-state structures with intra- and intermolecular hydrogen bonds. Keywords: aryl isocyanate; aryl isothiocyanate; carbamoylation; sulfonyl isocyanate; triaminoguanidinium salt; 1H-1,2,4-triazole-5(4H)-thione; Introduction The 1,2,3-triaminoguanidinium ion, [C(NHNH2)3

• tris(thiourea) derivative, could result. With phenyl isothiocyanate and its 4-nitro derivative, however, 3-hydrazinyl-1H-1,2,4-triazole-5(4H)-thiones 10a,b were obtained as major products in 57 and 68% yield, respectively (Scheme 5). In the case of (4-nitrophenyl) isothiocyanate, the bis(arylthiourea

Expeditive synthesis of trithiotriazine-cored glycoclusters and inhibition of Pseudomonas aeruginosa biofilm formation

• Meriem Smadhi,
• Sophie de Bentzmann,
• Anne Imberty,
• Marc Gingras,
• Raoudha Abderrahim and
• Peter G. Goekjian

Beilstein J. Org. Chem. 2014, 10, 1981–1990, doi:10.3762/bjoc.10.206

• modifying π–π-interactions and by favoring hydrogen-bonding to water. These compounds also lack the hydrophobic peripheral benzene units of the previous glycoasterisk ligands. They were replaced with a methylene-triazole linker in order to increase water solubility and to modulate the degree of flexibility

• dimethyldioxirane (DMDO) generated in situ in the presence of a phase-transfer catalyst, followed by treatment with NaN3 [39]. This afforded the silyl-protected D-galactose trithiotriazine–triazole glycocluster 11 under CuSO4/sodium ascorbate-catalyzed cycloaddition conditions [40] (20 °C, 24 h), in a satisfactory

• signals corresponding to the residual alkynes in the NMR and MS. The connectivity was established thanks to HMBC 3J proton–carbon correlations between the anomeric proton of the sugar and the triazole methine carbon (H-1–C-d), between the trizaole methine carbon and the thiomethylene protons (C-d–H-b

Facile synthesis of 1-alkoxy-1H-benzo- and 7-azabenzotriazoles from peptide coupling agents, mechanistic studies, and synthetic applications

• Mahesh K. Lakshman,
• Manish K. Singh,
• Mukesh Kumar,
• Raghu Ram Chamala,
• Vijayender R. Yedulla,
• Domenick Wagner,
• Evan Leung,
• Lijia Yang,
• Asha Matin and
• Sadia Ahmad

Beilstein J. Org. Chem. 2014, 10, 1919–1932, doi:10.3762/bjoc.10.200

• ][1,2,3]triazole, via in situ formation of pyrrolidine enamines and Pd catalysis. Keywords: alkoxy; azabenzotriazole; benzotriazole; peptide-coupling; phosphonium; Introduction Benzotriazole derivatives are of importance in diverse contexts. As examples, in medicinal chemistry substituted benzotriazoles

• properties, particularly against the human pathogen Acanthamoeba that can infect a variety of organs such as brain, eyes, skin, and lungs [4]. Triazole and benzotriazole derivatives have been evaluated as antitumor agents, with several showing high activities [5], and a benzotriazole derivative was shown to

• [29]. Although BOP did not react with MeOH in the absence of a base, in the presence of Cs2CO3 rapid formation of HMPA was observed and 1-methoxy-1H-benzotriazole (1-methoxy-1H-benzo[d][1,2,3]triazole) was isolated [29]. This evidence clearly showed that alcohols are capable of reaction with BOP in

Synthesis of a bifunctional cytidine derivative and its conjugation to RNA for in vitro selection of a cytidine deaminase ribozyme

• Nico Rublack and
• Sabine Müller

Beilstein J. Org. Chem. 2014, 10, 1906–1913, doi:10.3762/bjoc.10.198

• protected with tert-butyldimethylsilyl (TBDMS) groups and the tris-silylated uridine 7 [30] was further reacted with POCl3, triazole and triethylamine (Figure 2). Among the procedures described for conversion of uridine into cytidine derivatives [31][32][33][34] we have chosen the path via a triazolyl

• Information File 1). Retrosynthetic analysis of the bifunctional cytidine derivative 1 for functionalization of a periodate-oxidized RNA library. Introduction of the triazolyl moiety into the uridine derivative 7 generating synthon 3. I: 4 equiv POCl3, 16 equiv triazole, 20 equiv NEt3, MeCN, 60 min at 0 °C

Clicked and long spaced galactosyl- and lactosylcalix[4]arenes: new multivalent galectin-3 ligands

• Silvia Bernardi,
• Paola Fezzardi,
• Gabriele Rispoli,
• Stefania E. Sestito,
• Francesco Peri,
• Francesco Sansone and
• Alessandro Casnati

Beilstein J. Org. Chem. 2014, 10, 1672–1680, doi:10.3762/bjoc.10.175

• spectroscopy, which displayed the disappearance of the alkyne protons and the appearance of the typical broad signal of 1,4-disubstituted triazole protons at 7.75–7.85 ppm (CD3OD/CDCl3). ESIMS (+) analyses showed peaks for the [M + 2Na]2+ and [M + 3Na]3+ adducts, which indicates the conjugation of all four

• synthesize the triazole-containing lactosylcalixarenes 3 and 4. We first attempted to prepare the lactoside derivative 14 by reacting peracetylated-lactose with 2-(2-(2-chloroethoxy)ethoxy)ethanol in the presence of BF3·Et2O [45]. However, we could only obtain a mixture of α and β-anomers (α/β ratio 2:3

Triazol-substituted titanocenes by strain-driven 1,3-dipolar cycloadditions

• Andreas Gansäuer,
• Andreas Okkel,
• Lukas Schwach,
• Laura Wagner,
• Anja Selig and
• Aram Prokop

Beilstein J. Org. Chem. 2014, 10, 1630–1637, doi:10.3762/bjoc.10.169

• the synthesis of triazole-substituted titanocenes via strain-driven 1,3-dipolar cycloadditions between azide-functionalized titanocenes and cyclooctyne has been developed. It features the first synthesis of titanocenes containing azide groups. These compounds constitute ‘second-generation

• ’ functionalized titanocene building blocks for further synthetic elaboration. Our synthesis is modular and large numbers of the complexes can in principle be prepared in short periods of time. Some of the triazole-substituted titanocenes display high cyctotoxic activity against BJAB cells. Comparison of the most

• -driven 1,3-dipolar cycloaddition is a convenient and very mild route to triazole-functionalized cationic titanocenes. The yields between 75% and 92% are satisfying. It should be noted that the polyether-substituted complexes 13 and 17 are obtained in high yield. This opens further interesting

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

• synthetic approach towards the preparation of functionalised, soluble, donor–acceptor (DA) alkylbithiophene derivatives of oxadiazole, thiadiazole and triazole is reported. Taking advantage of the Fiesselmann reaction, reactive bithiophene synthons having alkyl or alkoxy substituents at designated positions

• synthesis, efficient ring closure reaction affording a 4H-1,2,4-triazole unit is presented. All target ambipolar compounds display strong photoluminescence with measured quantum yields up to 0.59. Modification of the demonstrated synthetic routes may be exploited for the preparation of longer, specifically

• functionalised oligothiophenes, coupled to other heteroaromatic cores. Keywords: bithiophene; donor–acceptor; luminescence; 1,3,4-oxadiazole; 1,3,4-thiadiazole; 4H-1,2,4-triazole; Introduction In the past two decades oligo- and polythiophenes gained a significant research interest due to their wide application

Orthogonal dual thiol–chloroacetyl and thiol–ene couplings for the sequential one-pot assembly of heteroglycoclusters

• Michele Fiore,
• Gour Chand Daskhan,
• Baptiste Thomas and
• Olivier Renaudet

Beilstein J. Org. Chem. 2014, 10, 1557–1563, doi:10.3762/bjoc.10.160

• (Scheme 1). Such derivatives have proved to be useful in bioconjugates chemistry [25] and for the preparation of thioether-linked tetravalent glycocyclopeptides which have shown highest inhibition against a model lectin in comparison with analogues bearing oxime and triazole linkage [26]. Glycosyl thiols