CuI-catalyzed synthesis of multisubstituted pyrido[1,2-]pyrimidin-4-ones through tandem Ullmann-type C-N cross-coupling and intramolecular amidation reaction.

Various multi-substituted pyrido[1,2-]pyrimidin-4-ones were synthesized a one-pot tandem CuI-catalyzed C-N bond formation/intramolecular amidation reaction at 130 °C in DMF. This protocol features simple operation, broad substrate scope, good functional group tolerance and gram scale preparation, thus allowing practical and modular synthesis of pyrido[1,2-]pyrimidin-4-ones from readily available 2-halopyridine and ()-3-amino-3-arylacrylate ester in good to excellent yields.

Novel lignin-supported copper complex as a highly efficient and recyclable nanocatalyst for Ullmann reaction.

In this work, we prepared polyhydroxylated lignin by demethylation and hydroxylation of lignin, and grafted phosphorus-containing groups by nucleophilic substitution reaction, the resulting material could be used as a carrier for the preparation of heterogeneous Cu-based catalysts (PHL-CuI-OPR). The optimal PHL-CuI-OPBu catalyst was characterized by FT-IR, TGA, BET, XRD, SEM-EDS, ICP-OES, XPS. The catalytic performance of PHL-CuI-OPBu in the Ullmann CN coupling reaction was evaluated using iodobenzene and nitroindole as model substrates under nitrogen atmosphere with DME and HO as cosolvent at 95 °C for 24 h.

Modeling epidemic spreading through public transit using time-varying encounter network.

Passenger contact in public transit (PT) networks can be a key mediate in the spreading of infectious diseases. This paper proposes a time-varying weighted PT encounter network to model the spreading of infectious diseases through the PT systems. Social activity contacts at both local and global levels are also considered.

Palladium-Catalyzed Synthesis of Fluorescent Benzo[4,5]imidazo[1,2-a]pyridines through Annulation Reaction of Benzimidazoles and Alkynyl Bromides with Internal Alkynes.

An efficient synthesis of fused azapolycycles based on (benz)imidazole and pyridine scaffolds has been developed. In all cases, the first nucleophilic addition of (benz)imidazoles to alkynyl bromides in pentyl alcohol can proceed in a stereoselective manner to provide ()--(1-bromo-1-alken-2-yl)benzimidazoles at 110 °C. Sequentially, these adducts containing alkenyl bromide can undergo Pd-catalyzed intermolecular C-H annulation in the presence of internal alkynes in dimethylacetamide, affording fluorescent (benz)imidazole-fused pyridines in good to high yields.

Copper(ii)-catalyzed synthesis of multisubstituted indoles through sequential Chan-Lam and cross-dehydrogenative coupling reactions.

Starting from arylboronic acids and ester ()-3-aminoacrylates, one-pot syntheses of diverse indole-3-carboxylic esters have been described through copper(ii)-catalyzed sequential Chan-Lam -arylation and cross-dehydrogenative coupling (CDC) reactions. The initial Chan-Lam arylation can proceed in DMF at 100 °C for 24 h to give ester ()-3-(arylamino)acrylate intermediates in the presence of Cu(OAc)/tri--butylphosphine tetrafluoroborate, a catalytic amount of myristic acid as the additive, KMnO and KHCO. Sequentially, these arylated intermediates can undergo an intramolecular oxidative cross-dehydrogenative coupling process in mixed solvents (DMF/DMSO = 2 : 1) at 130 °C to give C3-functionalized multi-substituted indole derivatives.

Palladium(II)-Catalyzed Oxidative Annulation of 2-Hydroxynaphthalene-1,4-diones and Internal Alkynes via C-H Functionalization.

An efficient Pd(II)-catalyzed oxidative annulation of 2-hydroxynaphthalene-1,4-diones and internal alkynes has been developed with high step efficiency. A broad range of functional groups are compatible with this reaction, thus providing a new entry to diverse naphtho[2,3-]furan-4,9-dione derivatives in good to high yields.

Palladium-catalyzed tandem one-pot synthesis of π-expanded imidazoles through a sequential Heck and oxidative amination reaction.

An efficient palladium-catalyzed route for tandem synthesis of imidazole-fused polyheterocycles from 2-vinyl imidazoles and aryl halides is described. The sequentially accomplished process comprises intermolecular Heck arylation of 2-vinyl imidazoles followed by an intramolecular aerobic oxidative C-H amination reaction promoted by the same Pd catalyst. This Pd-catalyzed tandem approach offers a straightforward protocol for the assembly of benzimidazo/phenanthroimidazo[1,2-a]quinolines in moderate to high yields, serving as a useful tool for the discovery of fluorescent materials.

Copper-Catalyzed Synthesis of Multisubstituted Indoles through Tandem Ullmann-Type C-N Formation and Cross-dehydrogenative Coupling Reactions.

Multisubstituted indoles were synthesized via a one-pot tandem copper-catalyzed Ullmann-type C-N bond formation/intramolecular cross-dehydrogenative coupling process at 130 °C in DMSO. The methodology allows practical and modular assembly of indoles in good to excellent yields from readily available aryl iodides and enamines.