Dearomative [4 + 2] Annulation of Electron-Poor N-Heteroarenes with Azoalkenes for Access to Polycyclic Tetrahydro-1,2,4-triazines.

A direct dearomative [4 + 2] annulation of electron-poor N-heteroarenes with azoalkenes generated in situ from α-halogeno hydrazones was developed under mild conditions. Accordingly, a series of fused polycyclic tetrahydro-1,2,4-triazines with potential biological activity were obtained in up to 96% yield. Various α-halogeno hydrazones and N-heteroarenes, such as pyridines, quinolines, isoquinolines, phenanthridine, and benzothiazole, were tolerated by this reaction.

Photo-induced catalytic halopyridylation of alkenes.

The Mizoroki-Heck reaction and its reductive analogue are staples of organic synthesis, but the ensuing products often lack a chemical handle for further transformation. Here we report an atom-economical cross-coupling of halopyridines and unactivated alkenes under photoredox catalysis to afford a series of alkene halopyridylation products. This protocol with mild and redox neutral conditions contributes broad substrate scope.

The serendipitous effect of KF in Ritter reaction: Photo-induced amino-alkylation of alkenes.

Ritter reaction has been recognized as an elegant strategy to construct the C-N bond. Its key feature is forming the carbocation for nucleophilic attack by nitriles. Herein, we report a complementary visible-light-induced three-component Ritter reaction of alkenes, nitriles, and -bromo nitriles/esters, thereby providing mild and rapid access to various -amino nitriles/acids.

Visible Light Induced Bifunctional Rhodium Catalysis for Decarbonylative Coupling of Imides with Alkynes.

Transition metal catalyzed decarbonylation offers a distinct synthetic strategy for new chemical bond formation. However, the π-backbonding between CO π* orbitals and metal center d-orbitals impedes ligand dissociation to regenerate the catalyst under mild reaction conditions. Developed here is visible light induced rhodium catalysis for decarbonylative coupling of imides with alkynes under ambient conditions.

Rhodium-catalyzed asymmetric hydrogenation of exocyclic α,β-unsaturated carbonyl compounds.

A highly enantioselective hydrogenation of exocyclic α,β-unsaturated carbonyl compounds catalyzed by Rh/bisphosphine-thiourea (ZhaoPhos) has been developed, giving the corresponding α-chiral cyclic lactones, lactams and ketones with high yields and excellent enantioselectivities (up to 99% yield and 99% ee). Remarkably, the hydrogen bond between the substrate and the catalyst plays a critical role in this transformation. The synthetic utility of this protocol has been demonstrated by efficient synthesis of chiral 3-(4-fluorobenzyl)piperidine, a key chiral fragment of bioactive molecules.

Enantioselective Rhodium-Catalyzed Cycloisomerization of 1,6-Allenynes to access 5/6-Fused Bicycle[4.3.0]nonadienes.

Transition-metal-catalyzed cycloisomerization of 1,n-allenynes represents a powerful synthetic tool to rapidly assemble complex polycyclic skeletons from simple linear substrates. Nevertheless, there are no reports of the asymmetric version of these reactions. Moreover, most of these reactions proceed through a 6-endo-dig cyclization pathway, which preferentially delivers the distal product (via 5/5 rhodacyclic intermediate) rather than the proximal one (via 6/5 rhodacyclic intermediate).

A cheap metal for a challenging task: nickel-catalyzed highly diastereo- and enantioselective hydrogenation of tetrasubstituted fluorinated enamides.

Nickel-catalyzed asymmetric hydrogenation of challenging tetrasubstituted fluorinated enamides has been achieved, affording chiral α-fluoro-β-amino esters in high yields with excellent diastereo- and enantioselectivities (up to 98% yield, >99 : 1 dr, up to >99% ee). Deuterium-labeling experiments and control experiments were conducted to probe the mechanism, and the results indicated that the acidity of the solvent plays a critical role in the control of diastereoselectivity by trapping the adduct of nickel hydride to C[double bond, length as m-dash]C bonds protonolysis, giving the hydrogenation product with stereospecific -selectivity. This protocol provides efficient access to chiral α-fluoro-β-amino esters which have important potential applications in organic synthesis and medicinal chemistry.

Iridium-Catalyzed Asymmetric Hydrogenation of Tetrasubstituted α-Fluoro-β-enamino Esters: Efficient Access to Chiral α-Fluoro-β-amino Esters with Two Adjacent Tertiary Stereocenters.

An iridium-catalyzed highly efficient asymmetric hydrogenation of challenging tetrasubstituted α-fluoro-β-enamino esters was successfully developed using bisphosphine-thiourea (ZhaoPhos) as the ligand, which prepared a series of chiral α-fluoro-β-amino esters containing two adjacent tertiary stereocenters with high yields and excellent diastereoselectivities/enantioselectivities (73%-99% yields, >25:1 dr, 91%->99% ee, and turnover number (TON) values up to 8600), and no defluorinate byproduct was detected.

Rhodium-catalyzed asymmetric hydrogenation of tetrasubstituted β-acetoxy-α-enamido esters and efficient synthesis of droxidopa.

A rhodium-catalyzed asymmetric hydrogenation of challenging tetrasubstituted β-acetoxy-α-enamido esters was developed, giving chiral β-acetoxy-α-amido esters in high yields with excellent enantioselectivities (up to >99% ee). The products could be easily transformed to β-hydroxy-α-amino acid derivatives which are valuable chiral building blocks and a novel route for the synthesis of droxidopa was also developed.

Enantioselective Rhodium-Catalyzed Cycloisomerization of (E)-1,6-Enynes.

An enantioselective rhodium(I)-catalyzed cycloisomerization reaction of challenging (E)-1,6-enynes is reported. This novel process enables (E)-1,6-enynes with a wide range of functionalities, including nitrogen-, oxygen-, and carbon-tethered (E)-1,6-enynes, to undergo cycloisomerization with excellent enantioselectivity, in a high-yielding and operationally simple manner. Moreover, this Rh(I) -diphosphane catalytic system also exhibited superior reactivity and enantioselectivity for (Z)-1,6-enynes.

Direct enantioselective vinylogous aldol-cyclization cascade reaction of allyl pyrazoleamides with isatins: asymmetric construction of spirocyclic oxindole-dihydropyranones.

The first enantioselective vinylogous aldol-cyclization cascade reaction of allyl pyrazoleamides with isatins is reported. With 1 mol% of Takemoto catalyst, optically active spirocyclic oxindole-dihydropyranones were obtained in excellent yields (93-99%) and good-to-excellent enantioselectivities (82-97% ee).

[Pathologic changes of the palatopharyngeal muscles in adult patients with obstructive sleep apnea hypopnea syndrome].

Objective: To investigate the pathology of palatopharyngeal muscle obtained from patients with obstructive sleep apnea hypopnea syndrome (OSAHS).

Methods: The samples from both groups were studied under HE, nicotinamide adenine dinucleotide-tetrazolium reductase (NADH- TR), modified Gomori trichrome (MGT) and adenosine triphosphatase (ATPase) staining. There were 36 cases of OSAHS who received uvulopalatopharyngoplasty in the experimental group (including 6 mild, 6 moderate and 24 severe cases).

Elevated frequencies of circulating Th22 cell in addition to Th17 cell and Th17/Th1 cell in patients with acute coronary syndrome.

Background: Atherosclerosis is a chronic inflammatory disease mediated by immune cells. Th22 cells are CD4(+) T cells that secret IL-22 but not IL-17 or IFN-γ and are implicated in the pathogenesis of inflammatory disease. The roles of Th22 cells in the pathophysiologic procedures of acute coronary syndrome (ACS) remain unclear.

[Rhabdomyolysis related to statin and seizures: report of 3 cases].

Objective: To investigate the clinical features and prognosis of rhabdomyolysis related to seizure attacks and use of statin.

Methods: The medical records of 3 patients with established diagnosis of rhabdomyolysis were analyzed and the related literatures were reviewed.

Results: All the 3 patients had seizure attacks and/or used statin before the onset of rhabdomyolysis.

The effects of statin on atrial fibrillation: a meta-analysis of published data from randomized controlled trials.

Background: Some clinical and experimental studies have shown the use of statins could protect against AF, but there are not adequate data at present.

Objectives: We performed a meta-analysis of randomized trials with statins on the endpoint of incidence of AF to estimate the impact of statin use on AF development.

Methods: We searched PUBMED, EMBASE and the Cochrane controlled Trials Register (Cochrane Library Issue 4, 2010) up to November 2010 to identify studies covering the use of statins on atrial fibrillation.

[Modified neurological tests for evaluating the severity of cerebral infarction and estimating the infarct area in rats].

Objective: To test the reliability of quantitative neurological tests in evaluating the neurological deficits in rat models of cerebral ischemia.

Methods: Forty male SD rats (7 to 9 weeks old) were subjected to transient (1 h) middle cerebral artery occlusion (MCAO) to induce cerebral infarction and 9 received sham operation only. The motor and sensory functions of the rats were measured before and 1, 3, 7 and 14 days after MCAO by accelerating rotarod test and modified adhesive removal test.