Search

A disulfide-tethered peptide–lipid conjugate self-assembled into a homogeneously distributed peptide–lipid hybrid vesicle. Upon dithiothreitol treatment, the homogeneous peptide–lipid membrane spontaneously divided into lipid-rich and peptide-rich domains, while the vesicle retained its size and shape. Membrane phase separation enhanced temperature-dependent cargo release. [ABSTRACT FROM AUTHOR]

The gamma C(sp3)–H bond alkynylation of R chains of amides R1C(O)NHR, a fundamental class of synthetic substrates, has not been accomplished to date. Here, the first example of palladium(ii)-catalyzed alkynylation of an unactivated gamma C(sp3)–H bond of alkyl amides (cyclic, linear, and amino acids) is reported. The kinetic experiment shows that the rate of the reaction depends on the coupling partners and the amides. Late-stage diversification of alkynylated amides was developed by utilizing amine and alkyne functionalities. [ABSTRACT FROM AUTHOR]

Tetrasubstituted alkene-based 1,2,3,4-tetrahydroisoquinolines are synthesized via the formation of a cyclic carbopalladation complex followed by C-H bond activation of the sp² carbon in arenes. This domino reaction proceeds with good selectivity and provides good yields of the products. The requisite starting materials are synthesized by copper(I) iodide catalyzed A³-coupling reactions. [ABSTRACT FROM AUTHOR]

A highly efficientand simple route for the synthesis of pyrrolo-/indolo[1,2-a]quinolines and naphtho[2,1-b]thiophenes from gem-dibromovinyls and sulphonamidesis reported. The noteworthy feature of this report is that the methodologyinvolves a two-step protocol to synthesize tri- and tetracyclic heterocyclesin a one-pot fashion through the Cu(I)-catalyzed formation of ynamidefollowed by a Ag(I)-assisted intramolecular hydroarylation. The photophysicalproperties of representative examples of pyrrolo- and indolo[1,2-a]quinolines in solid and solution states have alsobeen studied. [ABSTRACT FROM AUTHOR]

Tetrasubstituted olefin based new xanthene derivatives have been synthesized via palladium-catalyzed carbopalladation/C–Hactivation of 2-bromobenzyl-N-propargylamine derivatives. The synthesized compounds display a pronounced solid state fluorescence due to their restricted internal rotation of a C–Ar bond in the solid or aggregation state. [ABSTRACT FROM AUTHOR]

An efficient, stereo- and regioselective palladium-catalyzed 6-exo-dig intramolecular hydroarylation of propargyl ethers which provides a concise access to functionalized isochromans in high yields has been developed. A wide range of substrates possessing aromatic, aliphatic and heteroaromatic alkynes can be efficiently transformed into the targeted isochromans. Irrespective of the nature of the substrates, the cyclization follows highly selective stereo- and regiochemistry. [ABSTRACT FROM AUTHOR]

(1) Background: The folate receptor (FR) is a target for cancer treatment and detection. Expression of the FR is restricted in normal cells but overexpressed in many types of tumors. Folate was conjugated with peptides for enhancing binding affinity to the FR. (2) Materials and Methods: For conjugation, folate was coupled with propargyl or dibenzocyclooctyne, and 4-azidophenylalanine was introduced in peptides for "click" reactions. We measured binding kinetics including the rate constants of association (ka) and dissociation (kd) of folate-peptide conjugates with purified FR by biolayer interferometry. After optimization of the conditions for the click reaction, we successfully conjugated folate with designed peptides. (3) Results: The binding affinity, indicated by the equilibrium dissociation constant (KD), of folate toward the FR was enhanced by peptide conjugation. The enhanced FR binding affinity by peptide conjugation is a result of an increase in the number of interaction sites. (4) Conclusion: Such peptide-ligand conjugates will be important in the design of ligands with higher affinity. These high affinity ligands can be useful for targeted drug delivery system. [ABSTRACT FROM AUTHOR]

The article reports on facile synthesis of 2-substituted Quinolines (III) and 3-Alkynyl-2-aryl-2H-indazole (V) via SnCl2-mediated reductive cyclization.

A simple and efficient Mn-catalyzed acylation of amines is achieved using both acyl and alkoxy functions of unactivated esters with the liberation of molecular hydrogen as a sole byproduct. The present protocol provides an atom-economical and sustainable route for the synthesis of amides from esters by employing an earth-abundant manganese salt and inexpensive phosphine-free tridentate ligand. [ABSTRACT FROM AUTHOR]

The gamma C(sp 3 )-H bond alkynylation of R chains of amides R 1 C(O)NHR, a fundamental class of synthetic substrates, has not been accomplished to date. Here, the first example of palladium(ii)-catalyzed alkynylation of an unactivated gamma C(sp 3 )-H bond of alkyl amides (cyclic, linear, and amino acids) is reported. The kinetic experiment shows that the rate of the reaction depends on the coupling partners and the amides. Late-stage diversification of alkynylated amides was developed by utilizing amine and alkyne functionalities.

The ability of hydrogen-transfer transition-metal catalysts, which enable increasingly rapid access to important structural scaffolds from simple starting materials, has led to a plethora of research efforts on the construction of heterocyclic scaffolds. Transition-metal-catalyzed hydrogen-transfer annulations are environmentally benign and highly atom-economical as they release of water and hydrogen as by-product and utilize renewable feedstock alcohols as starting materials. Recent advances in this field with respect to the annulations of alcohols with various nucleophilic partners, thus leading to the formation of heterocyclic scaffolds, are highlighted herein., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Palladium-catalyzed highly regio- and stereoselective 6-exo-dig and 7-endo-dig cyclization of functionalized propargylic compounds has been developed for the synthesis of (E)-4-(isobenzofuran-1(3H)-ylidene)-1,2,3,4-tetrahydroisoquinolines and aze/oxepinoindoles.