Asymmetric Catalytic 1,2-Azaarene Migration to α-Azaaryl-α-Hydroxy Esters Enabled by a Tailored Ligand.

Despite their prevalence in bioactive molecules, the stereoselective construction of α-azaaryl-α-hydroxycarboxylates remains a formidable challenge. Notably, although the benzilic ester rearrangement (BER) is an efficient approach to α-hydroxycarboxylates, asymmetric catalytic BER remains poorly developed, largely due to poor stereorecognition of the vicinal diketone substituents by common chiral catalysts. In response to these issues, here we report a copper-catalyzed asymmetric BER of azaarene-derived 1,2-diketones with simple alcohols to give diverse α-azaaryl-α-hydroxy esters.

Switchable skeletal editing of quinolines enabled by cyclizative sequential rearrangements.

The rapid diversification of core ring structures in complex molecules through switchable skeletal editing is valuable in the drug discovery process. However, controllable methods for chemically divergent modifications of azaarene frameworks using common substrates are challenging, despite the potential to maximize structural diversity and complexity. Here we report the tunable skeletal editing of quinolines through Brønsted acid-catalysed multicomponent reactions of quinoline N-oxides, dialkyl acetylenedicarboxylates and water to generate nitrogen-containing heteroaromatic compounds together with linear compounds in a modular fashion.

Enamine Acylation Enabled Desymmetrization of Malonic Esters.

Asymmetric enamine alkylation represents a powerful tool for stereoselective C-C bond formation; in contrast, the development of enantioselective enamine acylation remains elusive. Here, we report that a chiral phosphoric acid can render an in-situ-formed enamine to undergo a stereoselective intramolecular α-carbon acylation, providing an alternative approach for the synthesis of useful pyrrolinones and indolinones bearing tetrasubstituted stereocenters. Utilizing an effective integration of the desymmetrization strategy and bifunctional organocatalysis, the first example of enantioselective enamine acylation is achieved by employing readily available aminomalonic esters and cyclic ketones.

Catalytic Asymmetric Cyclizative Rearrangement of Anilines and Vicinal Diketones to Access 2,2-Disubstituted Indolin-3-ones.

The efficient synthesis of chiral 2,2-disubstituted indolin-3-ones is of great importance due to its significant synthetic and biological applications. However, catalytic enantioselective methods for de novo synthesis of such heterocycles remain scarce. Herein, a novel cyclizative rearrangement of readily available anilines and vicinal diketones for the one-step construction of enantioenriched 2,2-disubstituted indolin-3-ones is presented.

Multicomponent Cyclizative 1,2-Rearrangement Enabled Enantioselective Construction of 2,2-Disubstituted Pyrrolinones.

The 1,2-rearrangement reaction is one of the most important approaches to construct carbon-carbon bonds in organic synthesis. However, the development of catalytic asymmetric 1,2-rearrangements is still far from mature and often suffers from problems such as complex substrates, single product structure, and lack of synthetic application. Multicomponent reaction has been recognized as a robust tool for the synthesis of diverse and tunable products from readily available starting material.

Symmetrical femtosecond laser arc incision in correcting corneal astigmatism in cataract patients.

Aim: To evaluate the effect of symmetrical arc incision correcting corneal astigmatism in femtosecond laser-assisted phacoemulsification (FLACS).

Methods: This study enrolled patients with cataract combined with regular corneal astigmatism of >0.75 D, who underwent FLACS.

Catalytic Enantioselective Biltz Synthesis.

The Biltz synthesis establishes straightforward access to 5,5-disubstituted (thio)hydantoins by combining a 1,2-diketone and a (thio)urea. Its appealing features include inherent atom and step economy together with the potential to generate structurally diverse products. However, control of the stereochemistry of this reaction has proven to be a daunting challenge.

Zinc chloride-catalyzed cyclizative 1,2-rearrangement enables facile access to morpholinones bearing aza-quaternary carbons.

Morpholines and morpholinones are important building blocks in organic synthesis and pharmacophores in medicinal chemistry, however, C3-disubstituted morpholines/morpholinones are extremely difficult to access. Here we show the ZnCl-catalyzed cyclizative 1,2-rearrangement for the efficient synthesis of morpholinones bearing aza-quaternary stereocenters. A series of structurally diverse C3-disubstituted morpholin-2-ones which are difficultly accessible by existing methods were efficiently constructed from readily available two achiral linear compounds.

Asymmetric Construction of α,α-Disubstituted Piperazinones Enabled by Benzilic Amide Rearrangement.

An unprecedent asymmetric catalytic benzilic amide rearrangement for the synthesis of α,α-disubstituted piperazinones is reported. The reaction proceeds via a domino [4+1] imidazolidination/formal 1,2-nitrogen shift/1,2-aryl or alkyl migration sequence, employing readily available vicinal tricarbonyl compounds and 1,2-diamines as starting materials. This approach provides an efficient access to chiral C3-disubsituted piperazin-2-ones with high enantiocontrol, which are exceedingly difficult to access from the existing synthetic methodologies.

Cerebral arterial air embolism after endobronchial electrocautery: a case report and review of the literature.

Background: Endobronchial electrocautery is a common and safe therapeutic endoscopic treatment for malignant airway obstruction. Cerebral arterial air embolism (CAAE) is a rare but potentially fatal complication of endobronchial electrocautery.

Case Presentation: We present the first case of cerebral arterial air embolism after endobronchial electrocautery.

Catalytic Enantioselective Synthesis of Morpholinones Enabled by Aza-Benzilic Ester Rearrangement.

Chiral morpholinone is an important building block in organic synthesis and a pharmacophore in medicinal chemistry. However, catalytic enantioselective methods for the construction of this ,-heterocycle remain scarce. We report herein a chiral phosphoric acid-catalyzed enantioselective synthesis of C3-substituted morpholinones from aryl/alkylglyoxals and 2-(arylamino)ethan-1-ols.

Catalytic Enantioselective Aminopalladation-Heck Cascade.

Domino processes initiated by intramolecular nucleopalladation of alkynes have been developed into powerful synthetic tools for the synthesis of functionalized heterocycles. However, a catalytic enantioselective version of this class of reactions remains scarce. We report herein that reaction of 2-alkynylanilines with prochiral cyclopentenes in the presence of a catalytic amount of Pd(OAc) , a chiral bidentate pyrox ligand and O as terminal oxidant affords the structurally diverse indole-cyclopentene conjugates bearing two stereocenters in a highly diastereo- and enantio-selective manner.

Palladium-Catalyzed Enantioselective Cacchi Reaction: Asymmetric Synthesis of Axially Chiral 2,3-Disubstituted Indoles.

We report herein the first examples of a palladium-catalyzed enantioselective Cacchi reaction for the synthesis of indoles bearing a chiral C2-aryl axis. In the presence of a catalytic amount of Pd(OAc) and (R,R)-QuinoxP* ligand, reaction of N-aryl(alkyl)sulfonyl-2-alkynylanilides with arylboronic acids under oxygen atmosphere afforded enantioenriched 2,3-disubstituted indoles in high yields and enantioselectivity. The indole ring is constructed de novo in this process and a complexation-induced chirality transfer is proposed to account for the observed enantioselectivity.

β-asarone and levodopa co-administration protects against 6-hydroxydopamine-induced damage in parkinsonian rat mesencephalon by regulating autophagy: down-expression Beclin-1 and light chain 3B and up-expression P62.

In this study, we investigated Beclin-1, light chain (LC)3B, and p62 expression in 6-hydroxydopamine (6-OHDA)-induced parkinsonian rats after β-asarone and levodopa (l-dopa) co-administration. Unilateral 6-OHDA injection into the medial forebrain bundle was used to create the models, except in sham-operated rats. Rats were divided into eight groups: sham-operated group; 6-OHDA model group; madopar group (75 mg/kg, per os (p.

Neuroprotective Effects of β-Asarone Against 6-Hydroxy Dopamine-Induced Parkinsonism via JNK/Bcl-2/Beclin-1 Pathway.

β-asarone, a major component of Acorus tatarinowii Schott, has positive effects in neurodegeneration disease, however, its effect on the Parkinson's disease (PD) remains unclear. In this study, the effects of β-asarone on behavioral tests, neurotransmitters, tyrosine hydroxylase (TH), and α-synuclein (α-syn) were investigated in 6-hydroxydopamine (6-OHDA) induced rats. Furthermore, the JNK/Bcl-2/Beclin-1 autophagy pathway was also studied.

Dynamic expressions of Beclin 1 and tyrosine hydroxylase in different areas of 6-hydroxydopamine-induced Parkinsonian rats.

Beclin 1, a regulator of the autophagy pathway, plays an important role in Parkinson's disease (PD). However, the crucial mechanism of Beclin 1 in PD remains unclear. Therefore, we investigated dynamic expressions of Beclin 1 and tyrosine hydroxylase (TH) in different brain areas of 6-OHDA-induced rats.

[Effects of qingyang toujie mixture in combination with prednisone tablet on Th1/Th2 cytokines in patients suffering from systemic lupus erythematosus].

Objective: To research the effects of Qingyang Toujie Mixture (QTM) in combination with prednisone tablet on the balance of Th1 and Th2 (Th1/Th2) of systemic lupus erythematosus (SLE) patients of yin deficiency syndrome (YDS).

Methods: Totally 42 patients with SLE were recruited from clinics of internal medicine and hospitalization department of First Hospital Affiliated to Guangzhou University of Traditional Chinese Medicine from August 2009 to March 2011. They were randomly assigned to the treatment group (22 cases) and the control group (20 cases) according to the random digit table.

Cascade hydroamination/redox reaction for the synthesis of cyclic aminals catalyzed by a combined gold complex and Brønsted acid.

Relay catalysis: An unprecedented protocol for the synthesis of cyclic aminals has been realized under the relay catalysis of a gold(I)/Brønsted acid binary system to generate cyclic aminals in excellent yields of up to 99 % with moderate to high diastereoselectivity (see scheme; up to 95:5 d.r.).

Direct access to enantioenriched spiroacetals through asymmetric relay catalytic three-component reaction.

The gold(I)/chiral Brønsted acid relay catalysis enabled a highly stereoselective three-component reaction of salicylaldehydes, anilines, and alkynols to give aromatic spiroacetals in high yields and stereoselectivities.

β-Asarone protects PC12 cells against OGD/R-induced injury via attenuating Beclin-1-dependent autophagy.

Aim: To explore the effects of β-asarone from Acorus Tatarinowii Schott on autophagy in an ischemic stroke model of PC12 cells.

Methods: The ischemic stroke model of PC12 cells was made by OGD/R (2 h oxygen-glucose deprivation followed by 24 h reperfusion). Drug administration was started 1 h before OGD and last for 3 h.

Beta-asarone attenuates ischemia-reperfusion-induced autophagy in rat brains via modulating JNK, p-JNK, Bcl-2 and Beclin 1.

Beta-asarone has significant pharmacological effects on the central nervous system. It can attenuate neuronal apoptosis, but its effects on the brain ischemia-reperfusion-induced autophagy have not been reported yet. Our study was a two-stage procedure: evaluation of β-asarone effects on the autophagy at first, and then analysis of the possible mechanism.