Nucleophilic Addition/Electrocyclization Strategy toward Polyheterocyclic-Fused Quinoline-2-thiones in Green Solvent

A metal-free and base-free cyclization reaction of ortho-heteroaryl anilines with isothiocyanatobenzene for the synthesis of diverse polyheterocyclic-fused quinoline-2-thiones was developed in PEG-200. This protocol features green solvent, lack of requirement for a metal and base, short reaction time consumption, and facile isolation via simple filtration. Furthermore, this protocol is easy to scale up which demonstrates outstanding synthetic scalability

Synthesis of Oligo(ethylenediamino)-<i>β</i>-Cyclodextrin Modified Gold Nanoparticle as a DNA Concentrator

A novel oligo(ethylenediamino)-β-cyclodextrin-modified gold nanoparticle (OEA-CD-NP) was synthesized as a vector for DNA binding and comprehensively investigated by means of absorption and circular dichroism spectroscopies as well as transmission electron microscopy, and its plasmid transfection efficiency as a carrier into cultivated cells in vitro was also evaluated. Possessing many hydrophobic cavities at the outer space, OEA-CD-NP may have a capability of carrying biological and/or medicinal substrates into cells, which will make it potentially applicable in many fields of material science and biological technology. In contrast with OEA-CD-NP, the oligo(ethylenediamino)-lipoic amido-modified gold nanoparticle (OEA-L-NP) without CD was synthesized to investigate the interaction with DNA. The results showed that OEA-L-NPs could only weakly bind DNA. Keywords: Nanoparticles; cyclodextrin; DNA; gene transfection; cytotoxicit

Procedure for the Synthesis of Polysubstituted Carbazoles from 3‑Vinyl Indoles

A simple Brønsted acid catalyzed tandem reaction, including intermolecular nucleophilic addition, substitution and intramolecular cyclization, in a one-pot manner is described. Thirty two 2-indolyl substituted carbazoles are generated in good to excellent yields. Based on this tandem reaction strategy, the poly­(1,4-carbazole) is prepared for the first time. Preliminary studies indicate that the poly­(1,4-carbazole) has good thermostability and optical properties

Cyclodextrin-Driven Movement of Cucurbit[7]uril

The movement of cucurbit[7]uril (CB[7]) driven by α-cyclodextrin (α-CD) is investigated by various experimental techniques including NMR, ESI-MS, UV−vis, and ITC. CB[7] can form stable pseudorotaxanes with N-methyl-N‘-octyl-4,4‘-bipyridinium (MVO2+) and N,N‘-dioctyl-4,4‘-bipyridinium (OV2+) dication in aqueous solution. CB[7] shuttles between the octyl and bipyridinium moieties in MVO2+, but docks at one of the octyl moieties in OV2+. The addition of α-CD pushes CB[7] from the octyl moiety of MVO2+ or OV2+ to the bipyridinium moiety. Thermodynamically, the movement of CB[7] is mainly driven by exothermic enthalpy changes coming from the complexation of the octyl moiety of MVO2+ or OV2+ with α-CD

Synthesis of Phosphoryl-Tethered β-Cyclodextrins and Their Molecular and Chiral Recognition Thermodynamics

Two novel phosphoryl-bridged bis- and tris(β-cyclodextrin)s of different tether lengths, i.e., bis[m-(N-(6-cyclodextryl)-2-aminoethylaminosulfonyl)phenyl]-m-(chlorosulfonyl)phenylphosphine oxide (5) and tris[m-(N-(6-cyclodextryl)-8-amino-3,6-diazaoctylaminosulfonyl)phenyl]phosphine oxide (6), have been synthesized by reactions of 6-oligo(ethylenediamino)-6-deoxy-β-cyclodextrins with tris[m-(chlorosulfonyl)phenyl]phosphine oxide. The complex stability constants (KS), standard molar enthalpy (ΔH°), and entropy changes (ΔS°) were determined at 25 °C for the inclusion complexation of phosphoryl-modified bis- and tris-cyclodextrins (5 and 6, respectively), mono[6-O-(ethoxyhydroxyphosphoryl)]-β-cyclodextrin (2), mono[6-O-(diethylamino-ethoxyphosphoryl)]-β-cyclodextrin (3), and mono[6-O-(diphenoxyphosphoryl)]-β-cyclodextrin (4) with representative alicyclic and N-Cbz-d/l-alanine guests in 0.1 M phosphate buffer solution at pH 7.2 by means of titration microcalorimetry. The thermodynamic parameters obtained indicate that the charge−dipole interaction between the phosphoryl moiety and the negatively charged guests, as well as the conformational difference of modified β-cyclodextrins in aqueous solution, significantly contribute to the inclusion complexation and the enhanced chiral discrimination. The interactions and binding modes between the hosts and chiral guests were further studied by two-dimensional NMR spectroscopy to elucidate the influence of the structural features of hosts on their increased chiral recognition ability and to establish the correlation between the conformation of the resulting complexes and the thermodynamic parameters obtained

Supramolecular Polypseudorotaxane with Conjugated Polyazomethine Prepared Directly from Two Inclusion Complexes of β-Cyclodextrin with Tolidine and Phthaldehyde

The supramolecular polypseudorotaxane (3) with π-conjugated polyazomethine is directly synthesized by the polycondensation of two simple inclusion complexes of β-cyclodextrin/o-tolidine (1) and β-cyclodextrin/p-phthaldehyde (2) and is comprehensively characterized by NMR, FTIR, circular dichroism spectra, powder X-ray diffraction, thermogravimetric (TG) and differential thermal analysis (DTA), scanning electron microscopy (SEM), and scanning tunneling microscopy (STM) both in solution and in the solid state. The results obtained have revealed linear microstructure of polypseudorotaxane 3 and different photophysical behavior as compared with the π-conjugated polyazomethine backbone (4). The present investigations prove a simple method for preparing supramolecular polypseudorotaxane by different complexes, which possess the potential to serve as molecular devices/machines and optical materials

Catalytic Asymmetric Nucleophilic Addition of 3‑Vinyl Indoles to Imines

The 3-vinyl indole is used as a nucleophile to react with aromatic and aliphatic imines. Chiral 3-substituted indoles bearing multiple functional groups are produced with up to 99% yield, a 98:2 <i>E</i>/<i>Z</i> ratio, and 97% ee. A possible mechanism is proposed to explain the observed stereoselectivities. This strategy provides an efficient way for the preparation of novel chiral 3-substituted indoles

Chiral Calcium Phosphate Catalyzed Asymmetric Alkenylation Reaction of Arylglyoxals with 3‑Vinylindoles

A highly efficient alkenylation reaction of arylglyoxals with 3-vinylindoles catalyzed by chiral calcium phosphate is described. Structurally diverse allylic alcohols bearing indole and carbonyl units are prepared in excellent yields, good diastereoselectivities, and high to excellent enantioselectivities. These products are good building blocks for the synthesis of polysubstituted chiral tetrahydrocarbozol-2-ones. The mechanism study indicates that the most likely role of the catalyst is to activate the hydrate of arylglyoxal and control the stereoselectivity via desymmetric coordination