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isolation, structure elucidation and inhibitory activity against LPS-induced NO production in macrophages

Catalyst-controlled divergent intermolecular cycloadditions of vinylaziridines with alkynes have been developed. By using [Rh(NBD)2]BF4 as the catalyst, a [3 + 2] cycloaddition reaction was achieved with broad substrate scope and high stereoselectivity under mild reaction conditions. Moreover, the chirality of vinylaziridines can be completely transferred to the [3 + 2] cycloadducts. When the catalyst was changed to [Rh(η(6)-C10H8) (COD)]SbF6, the alternative [5 + 2] cycloadducts were selectively formed under otherwise identical conditions.

The first rhodium-catalyzed intramolecular hetero-[5+2] cycloaddition reaction of vinyl aziridines and alkenes was realized, wherein both internal and terminal alkenes were applicable. With this method, a variety of unique substituted chiral fused bicyclic azepines, bearing multiple contiguous stereogenic centers, were facilely accessed in a straightforward, high-yielding, and highly stereoselective manner under mild reaction conditions. Notably, the E/Z geometry of the CC bonds in the vinyl aziridine-alkene substrates impact the cis/trans stereochemistry of the cycloadducts and up to six stereoisomers could be delivered.

A series of 3-pyrazolylisoindolinone derivatives were synthesized by a concise, efficient, three-component reaction of a 2-formylbenzoic acid, a primary amine (or ammonium hydroxide), and a pyrazolone under catalyst-free conditions. This novel procedure has the advantages of easy handling, mild reaction conditions, and a wide substrate scope, and can be performed as a one-pot operation.

An efficient catalyst-free synthesis of 3′-benzoyl-4′,5′-diphenyl-2H-spiro[acenaphthylene-1,2′-pyrrolidin]-2-one derivatives via one-pot 1,3-dipolar cycloaddition of acenaphthenequinone, arylmethyl amines, and chalcones with high regioselectivity is described. The structure of the cycloadducts were characterized by infrared, high-resolution mass spectrometry (electrospray ionization), 1H NMR, and 13C NMR spectra, and the structure of 4a was confirmed using x-ray single-crystal structure analysis.

It is demonstrated, that the stereochemical information of vinyl-alkyne substrates containing a chiral aziridine substituent can be transferred to fused dihydroazepine derivatives by a Rh-catalyzed formal [5 + 2] cyclization.

A variety of the title spiro-compounds (IV) (17 examples) are synthesized via a NaHCO3-catalyzed three-component reaction.

An efficient one-pot synthesis of 5H-spiro[benzo[7,8]chromeno[2,3-c]pyrazole-7,3′-indoline]-2′,5,6(9H)-trione derivatives via a four-component reaction of hydrazine hydrate, β-keto esters, isatins, and 2-hydroxynaphthalene-1,4-dione catalyzed by MgCl2 in ethanol is reported. This reaction provides the advantages of excellent yields, environmental friendliness solvent, simple workup procedure, and short reaction time.

Recent years have witnessed a huge renaissance in the study of the structures and molecular magnetism of 4f-coordination compounds. In particular, lanthanide single-molecule magnets (Ln-SMMs) have become of increasing interest as the anisotropic barrier records have toppled like dominoes. Among them, tetranuclear Dy 4 compounds have played a key role in elucidating the magnetic relaxation dynamics of Ln-SMMs. In this review, the design and magnetic relaxation behavior of tetranuclear Dy 4 SMMs with diverse metal core structural types are discussed in detail with the goal of identifying features relevant to modulating relaxation dynamics of SMMs. The meaningful structure–property relationship obtained will improve our understanding of the magnetic behavior of SMMs and facilitate their potential applications in data storage and processing, essential for the rational design of new molecular-based materials.

The catalyst can be recycled and reused at least 5 times with only a slight decrease in conversion.

The title compounds (III) and (V) are obtained by reaction of various isatins or acenaphthenequinone, resp., with indoles under mild reaction conditions.

An unprecedented example for the selective and efficient synthesis of an FBT–thiophene structural motif via dual C–H functionalization, catalyzed by palladium, has been developed. Fluorinated benzotriazole is also applicable to the reaction. This protocol provides facile access to unsymmetrical and symmetrical thienylated FBTs that can be applied in the development of high performance photovoltaics, in particular in bulk heterojunction (BHJ) solar cells.

Diversifolide [4, 15-dinor-3-hydroxy-1(5)-xanthen-12, 8-olide], a novel dinorxanthane sesquiterpene, and a new chromone, 6-acetyl-7-hydroxy-2, 3-dimethylchromone, together with four known compounds, 2-deacetyl-11β, 13-dihydroxyxanthinin, 2-acetyl-2, 2-dimethylchromene, 6-acetyl-7-hydroxy-2, 2-dimethylchromene, and 6-acetyl-7-methoxy-2, 2-dimethylchromene were isolated from the root of Tithonia diversifolia. Their structures were spectroscopically determined by 2D-NMR experiments, including heteronuclear multiple bond correlation and nuclear Overhauser enhancement spectroscopy.

An efficient, multigram-scale synthesis of dihydronaphthofuranone 1 using a novel aryl intramolecular Diels–Alder reaction of propargyl trans -cinnamate 8 is described. Catalytic reduction of 1 gave the cis -fused tetrahydronaphthofuranone derivative 2 .

The catalytic enantioselective synthesis of all-carbon quaternary stereogenic centers in spirocyclic diketones has been achieved for the first time by an unprecedented asymmetric vinylogous α-ketol rearrangement in which an enantiocontrolled semipinacol-type 1,2-carbon migration was realized using multifunctional cinchona-modified primary amine catalysis.

An efficient method has been developed for the Barbier–Grignard-type alkylation reaction of aldehydes (including aliphatic version) using unactivated alkyl halides in water in the presence of an In/CuI/I2 or In/AgI/I2 system. The reactions proceeded more efficiently in water than in organic solvent. In, CuI or AgI, and I2 were all essential for the efficient progress of the reactions. A radical-type reaction mechanism was studied and proposed by using 4-pentenal as substrate.

Six novel ionic phosphine ligands with a cobaltocenium backbone, 1,1′-bis(dicyclohexylphosphino) cobaltocenium hexafluorophosphate ( di- cypc + PF 6 - ) (1a), 1,1′-bis(di-iso-propylphosphino) cobaltocenium hexafluorophosphate ( di- isoppc + PF 6 - ) (2a), 1,1′-bis(di-tert-butylphosphino) cobaltocenium hexafluorophosphate ( di- tbpc + PF 6 - ) (3a), and the monophosphine ligand Cc + PR 2 PF 6 - (Cc+ = cobaltocenium; R = Cy, 1b; R = i-Pr, 2b; R = t-Bu, 3b) were synthesized and characterized by elemental analysis, spectroscopy, and X-ray diffraction techniques. These ligands are air-stable and useful for Suzuki coupling reactions in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ( BMIM + PF 6 - ), enabling high catalytic activity.