Reversible end-to-end assembly of selectively functionalized gold nanorods by light-responsive arylazopyrazole–cyclodextrin interaction

• Maximilian Niehues,
• Patricia Tegeder and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2019, 15, 1407–1415, doi:10.3762/bjoc.15.140

• of gold nanorods (AuNR) by thiolated cyclodextrin (CD) host molecules. As a result of the complete removal of the precursor capping agent cetyltrimethylammonium bromide (CTAB) by a tetraethylene glycol derivative, competitive binding to the host cavity was prevented, and reversible, light-responsive

• advantage of the different ligand exchange kinetics of CTAB on the ends and the side of the particles [14][15]. CTAB serves as a capping agent in AuNR synthesis by the seed-mediated growth process and is essential for the anisotropic growth. Due to the different crystallographic environments on the particle

• potential and therefore about the capping agent (Figure 1a). CTAB-functionalized AuNR have a highly positive surface charge (+55 mV) due to the formation of CTAB double layers. The intermediate state [tCD]AuNR shows a decreased surface charge (+42 mV) indicating a reduction of the CTAB surface coverage. It

Electrophilic oligodeoxynucleotide synthesis using dM-Dmoc for amino protection

• Shahien Shahsavari,
• Dhananjani N. A. M. Eriyagama,
• Bhaskar Halami,
• Vagarshak Begoyan,
• Marina Tanasova,
• Jinsen Chen and
• Shiyue Fang

Beilstein J. Org. Chem. 2019, 15, 1116–1128, doi:10.3762/bjoc.15.108

• phosphoramidite capping agent 25. Synthesis of ester-containing phosphoramidite 26a. ODN deprotection and cleavage under non-nucleophilic conditions. Supporting Information Supporting Information File 181: Experimental details, compound characterization, and protocol for ODN cleavage and deprotection. Supporting

Homo- and hetero-difunctionalized β-cyclodextrins: Short direct synthesis in gram scale and analysis of regiochemistry

• Gábor Benkovics,
• Mihály Bálint,
• Éva Fenyvesi,
• Erzsébet Varga,
• Szabolcs Béni,
• Konstantina Yannakopoulou and
• Milo Malanga

Beilstein J. Org. Chem. 2019, 15, 710–720, doi:10.3762/bjoc.15.66

• many serious drawbacks such as unwanted over-substitution (multiple capping [13][14]), connection of two or more β-CD molecules through intermolecular disulfonyl bridges and partial hydrolysis of the capping agent during the work-up. Consequently, a chromatographic purification is essential for the

• identification, the authentic diazido compounds with known regiochemistry were synthesized using the appropriately spaced disulfonate capping agent, followed by azide opening of the cap and by chromatographic purification of the diazidated fractions [11][12] (reference reactions 1–3, Scheme 1). Direct

A tutorial review of stereoretentive olefin metathesis based on ruthenium dithiolate catalysts

• Daniel S. Müller,
• Olivier Baslé and
• Marc Mauduit

Beilstein J. Org. Chem. 2018, 14, 2999–3010, doi:10.3762/bjoc.14.279

• ruthenium complex. In situ methylene capping strategy for stereoretentive metathesis. Stereoretentive cross-metathesis with (Z)-butene (Z-25) as in situ methylene capping agent; selected applications. Cross metathesis with Z- and E-trisubstituted allylic alcohols. In situ synthesis of Ru-3 and application

Enhanced single-isomer separation and pseudoenantiomer resolution of new primary rim heterobifunctionalized α-cyclodextrin derivatives

• Iveta Tichá,
• Gábor Benkovics,
• Milo Malanga and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2018, 14, 2829–2837, doi:10.3762/bjoc.14.261

• almost no preferential selectivity for AB, AC or AD regioisomers. Breslow et al. [17] used the 1,3-dimethoxy-4,6-benzenedisulfonyl chloride as a capping agent to prepare the AB regioisomer. Subsequently, Fujita et al. [18] selectively capped the primary rim of α-CD using a special, sterically hindered

An alternative to hydrogenation processes. Electrocatalytic hydrogenation of benzophenone

• Cristina Mozo Mulero,
• Alfonso Sáez,
• Jesús Iniesta and
• Vicente Montiel

Beilstein J. Org. Chem. 2018, 14, 537–546, doi:10.3762/bjoc.14.40

• using NaBH4 as reducing agent in a water-in-oil (w/o) microemulsion in the presence of polyethylene glycol hexadecyl ether, Brij@30 as capping agent and n-heptane as organic solvent (water/Brij@30/n-heptane). After precipitation and copiously washing with acetone and water, Pd nanoparticles were

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• ]. Jang and co-workers reported a mechanochemical synthesis of benzimidazoles [143][144], benzoxazole [145] and benzothiazole derivatives in presence of ZnO nano particles as catalyst [146]. Using 0.5 mol % of ZnO nano particles which were grown on aromatic imine D as capping agent, resulted in the best

Encapsulation of biocides by cyclodextrins: toward synergistic effects against pathogens

• Véronique Nardello-Rataj and
• Loïc Leclercq

Beilstein J. Org. Chem. 2014, 10, 2603–2622, doi:10.3762/bjoc.10.273

• several papers [82][83]. In 2010, Jaiswal et al. proposed to use of β-CD as a capping agent [84]. The reduction of silver salts using sodium borohydride followed by β-CD capping allows the synthesis of stable spherical silver nanoparticles. The authors proved by dynamic light scattering that the average

• organic to the aqueous phase containing β-CD as a capping agent [85]. The “β-CD/silver” nanoparticles were purified and characterized by spectroscopic and microscopic analyses. The results showed that the encapsulation confered a considerable stability to the nanoparticles. Moreover, the silver

End-labeled amino terminated monotelechelic glycopolymers generated by ROMP and Cu(I)-catalyzed azide–alkyne cycloaddition

• Ronald Okoth and
• Amit Basu

Beilstein J. Org. Chem. 2013, 9, 608–612, doi:10.3762/bjoc.9.66

• Ronald Okoth Amit Basu Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA 10.3762/bjoc.9.66 Abstract Functionalizable monotelechelic polymers are useful materials for chemical biology and materials science. We report here the synthesis of a capping agent that can be

• accomplished by amidation with an azido-amine linker followed by Cu(I)-catalyzed azide–alkyne cycloaddition with propargyl sugars. Subsequent Teoc deprotection and conjugation with pyrenyl isothiocyanates afforded well-defined end-labeled glycopolymers. Keywords: capping agent; carbohydrate; glycan; olefin

• acid at the polymer terminus [6], a cis-alkene pentafluorophenol ester based terminating agent that introduces an amine-reactive capping agent [13], and cis-olefin terminating agents that directly introduce biotin and fluorescein at the polymer terminus [14]. A recent report describes the use of a cis