Influence of the milling parameters on the nucleophilic substitution reaction of activated β-cyclodextrins

• László Jicsinszky,
• Kata Tuza,
• Giancarlo Cravotto,
• Andrea Porcheddu,
• Francesco Delogu and
• Evelina Colacino

Beilstein J. Org. Chem. 2017, 13, 1893–1899, doi:10.3762/bjoc.13.184

• that it never exceeded 72 °C. Further, no degradation of the activated Ts-β-CD was observed. The yield of the mechanically induced azidation is invariably higher than the one observed in our previous work [13]. However, the rate of the reaction involving the more nucleophilic TU is considerably lower

Strategies toward protecting group-free glycosylation through selective activation of the anomeric center

• A. Michael Downey and
• Michal Hocek

Beilstein J. Org. Chem. 2017, 13, 1239–1279, doi:10.3762/bjoc.13.123

Solid-phase enrichment and analysis of electrophilic natural products

• Frank Wesche,
• Yue He and
• Helge B. Bode

Beilstein J. Org. Chem. 2017, 13, 405–409, doi:10.3762/bjoc.13.43

• ) [16][17]. The azidation was carried out with sodium azide and ammonium chloride in 80% MeOH under reflux overnight (Supporting Information File 1, Figure S2). The azido alcohol was then incubated with CARR (2) in acetonitrile overnight followed by extensive washing of the resin with methanol and

• without formation of the other possible regioisomer. For further structural confirmation, P. luminescens TT01 was cultivated in 13C-labeled medium prior to the azidation and enrichment procedure indeed confirming the incorporation of 17 carbon atoms in 3 (Supporting Information File 1, Figure S5

• 1. Encouraged by these results and especially the high sensitivity of the method, the azidation was performed with XAD extracts of three additional Photorhabdus strains (Photorhabdus PB45.5, Photorhabdus PB 68.1 and Photorhabdus temperata subsp. thracensis DSM 15199). Here, an even lower amount of 3

Synthesis of multi-lactose-appended β-cyclodextrin and its cholesterol-lowering effects in Niemann–Pick type C disease-like HepG2 cells

• Keiichi Motoyama,
• Rena Nishiyama,
• Yuki Maeda,
• Taishi Higashi,
• Yoichi Ishitsuka,
• Yuki Kondo,
• Tetsumi Irie,
• Takumi Era and
• Hidetoshi Arima

Beilstein J. Org. Chem. 2017, 13, 10–18, doi:10.3762/bjoc.13.2

• -specific cholesterol-lowering agent. The schematic representation of the synthesis of multi-Lac-β-CD (5) is shown in Figure 1. Briefly, per-NH2-β-CD (4) was synthesized by chlorination (per-chloro-β-CD (2)) and azidation (per-azido-β-CD (3)) of primary hydroxy groups of β-CD 1, as reported previously [17

Beta-hydroxyphosphonate ribonucleoside analogues derived from 4-substituted-1,2,3-triazoles as IMP/GMP mimics: synthesis and biological evaluation

• Tai Nguyen Van,
• Audrey Hospital,
• Corinne Lionne,
• Lars P. Jordheim,
• Charles Dumontet,
• Christian Périgaud,
• Laurent Chaloin and
• Suzanne Peyrottes

Beilstein J. Org. Chem. 2016, 12, 1476–1486, doi:10.3762/bjoc.12.144

• Information File 1). NMR studies To establish the stereochemistry and/or regiochemistry of the azidation and CuAAC steps, homo- or heteronuclear 2D NMR experiments (see Supporting Information File 2) were performed on compounds 2 and 3a (Figure 2). In addition, we synthesized compound 5 (resulting from an 1,5

Cholesterol lowering effects of mono-lactose-appended β-cyclodextrin in Niemann–Pick type C disease-like HepG2 cells

• Keiichi Motoyama,
• Yumi Hirai,
• Rena Nishiyama,
• Yuki Maeda,
• Taishi Higashi,
• Yoichi Ishitsuka,
• Yuki Kondo,
• Tetsumi Irie,
• Takumi Era and
• Hidetoshi Arima

Beilstein J. Org. Chem. 2015, 11, 2079–2086, doi:10.3762/bjoc.11.224

• present study, we attempted to prepare Lac-β-CyD as a hepatocyte-selective cholesterol decreasing agent. Figure 1 shows the preparation pathway of Lac-β-CyD. Firstly, we synthesized NH2-β-CyD through tosylation, and azidation of primary hydroxy groups of β-CyD, as reported previously [12][13]. Secondly

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

Synthetic strategies for the fluorescent labeling of epichlorohydrin-branched cyclodextrin polymers

• Milo Malanga,
• Mihály Bálint,
• István Puskás,
• Kata Tuza,
• Tamás Sohajda,
• László Jicsinszky,
• Lajos Szente and
• Éva Fenyvesi

Beilstein J. Org. Chem. 2014, 10, 3007–3018, doi:10.3762/bjoc.10.319

• azido groups The introduction of the azido groups into the β-CD-polymer has been performed by adapting the sequence iodination → azidation [19] to the specific structure. The target was to introduce one azido moiety per CD ring in 0.5–2% of the CD population. The optimization of the three-step reaction

• the same reasons the work-up and the purification steps had to be carefully planned without relying on chromatographic techniques. Taken into consideration that the azidation step is an exhaustive process (if NaN3 is used in excess), the real challenge was to control the degree of the iodination. In

• complicated by the impossibility to follow the progress of the reaction by TLC. The optimized reaction conditions for the azidation of the β-CD-polymer are shown in Scheme 2 while the work-up procedure is reported in detail in the experimental part (see Supporting Information File 1). Concerning the

A versatile δ-aminolevulinic acid (ΑLA)-cyclodextrin bimodal conjugate-prodrug for PDT applications with the help of intracellular chemistry

• Chrysie Aggelidou,
• Theodossis A. Theodossiou,
• Antonio Ricardo Gonçalves,
• Mariza Lampropoulou and
• Konstantina Yannakopoulou

Beilstein J. Org. Chem. 2014, 10, 2414–2420, doi:10.3762/bjoc.10.251

• azidation to 7. Finally, enzymatic cleavage of the ester [15] resulted in liberation of the carboxylic acid functionality that is required for the coupling to the CD (Scheme 2, compound 8, Figure S1, Figure S2 in Supporting Information File 1). The connection of 8 to 4 proceeded under standard coupling

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

• 1,3-diketones follow condensation/cyclization pathways resulting in unsymmetrical N-heterocyclic products [14][15]. Azidation of TAG-Cl with two equivalents of sodium nitrite in water afforded the highly shock- and friction-sensitive (5-azido-1H-tetrazol-1-yl)carbonimidoyl diazide rather than the

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

• to the electrophile compared to the conventionally accepted model [31]. The use of other electrophiles for the stereoselective formation of C–N bonds has also been reported. Thus, α-amino-α-alkyl phosphonic acids [32][33][34] could be obtained through amination and azidation of phosphonamide anions

Atherton–Todd reaction: mechanism, scope and applications

• Stéphanie S. Le Corre,
• Mathieu Berchel,
• Hélène Couthon-Gourvès,
• Jean-Pierre Haelters and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2014, 10, 1166–1196, doi:10.3762/bjoc.10.117

• phosphorazidate (DPPA) and diethyl phosphorocyanidate (DEPC) are widely employed as peptide coupling reagents [59][60][61][62]. DPPA was also used in many organic reactions such as the Curtius rearrangement [59], the thiol ester synthesis [63], the azidation of alcohol and phenol [64], and the synthesis of

Stereodivergent synthesis of jaspine B and its isomers using a carbohydrate-derived alkoxyallene as C₃-building block

• Volker M. Schmiedel,
• Stefano Stefani and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2013, 9, 2564–2569, doi:10.3762/bjoc.9.291

• therefore leads to a stereodivergent approach to the natural product and its enantiomer. The gold-catalyzed 5-endo-cyclization affords the corresponding dihydrofurans, which after separation, azidation of the enol ether moiety and two subsequent reduction steps give the natural product and its stereoisomers

• of both diastereomers. The cis-configured amino alcohol moiety at C-3 and C-4 is installed by azidation and subsequent reduction steps leading to the final products. The presented strategy allows the preparation of jaspine B, its enantiomer and two diastereomers, all of which are known for their

• pleased to discover that the oxidative azidation [36] allowed a direct access to the corresponding α-azidofuranones in one step. The two diastereomers of the azides were obtained in a 60:40 ratio. The subsequent reduction of the carbonyl group with L-selectride in THF furnished the α

Design and synthesis of tag-free photoprobes for the identification of the molecular target for CCG-1423, a novel inhibitor of the Rho/MKL1/SRF signaling pathway

• Jessica L. Bell,
• Andrew J. Haak,
• Susan M. Wade,
• Yihan Sun,
• Richard R. Neubig and
• Scott D. Larsen

Beilstein J. Org. Chem. 2013, 9, 966–973, doi:10.3762/bjoc.9.111

• began with the acetylation of 4-chloro-3-nitroaniline (9) followed by reduction of the nitro group using iron and hydrochloric acid to generate aniline 10. The azido group was introduced by diazotization/azidation to provide 11. Deacetylation with potassium hydroxide revealed aniline 12, which was then

• azide and acetylene, was prepared from aniline 26. Introduction of the azide was accomplished via diazotization/azidation, followed by standard amide coupling of 27 and 18 to afford final aryl azide photoprobe 28. Table 2 summaries the biological data for the four final candidate photoprobes

Synthesis of trifunctional cyclo-β-tripeptide templates

• Frank Stein,
• Tahir Mehmood,
• Tilman Plass,
• Javid H. Zaidi and
• Ulf Diederichsen

Beilstein J. Org. Chem. 2012, 8, 1576–1583, doi:10.3762/bjoc.8.180

• -homolysine side chain to an azide [12][13][14] employing the Wong azidation [15] enables Huisgen [3 + 2]-cycloaddition [16] as an orthogonal coupling method. In order to build up the peptide sequence in the presence of Fmoc, Cbz and the azide, an acid-labile protecting group was required for temporary