“On Water” Organocatalyzed [4 + 2] Cycloaddition of Enones and Nitro Dienes for the Enantioselective Synthesis of Densely Substituted Cyclohexanones

Copper-Catalyzed Stereoselective [4 + 2] Cycloaddition of β,γ-Unsaturated α-Keto Esters and 2-Vinylpyrroles in Water

An asymmetric [4 + 2] cycloaddition of β,γ-unsaturated α-keto esters with 2-vinylpyrroles in water was developed under the catalysis of a kind of copper complex with a low loading. A series of optically pure 3,4-dihydro-2H-pyran derivatives could be obtained in excellent yields, with high diastereoselectivities and enantioselectivities. The corresponding mechanism was proposed, which was supported by DFT calculations.

Diels-Alder Cycloaddition Reactions in Sustainable Media

Diels–Alder cycloaddition reaction is one of the most powerful strategies for the construction of six-membered carbocyclic and heterocyclic systems, in most cases with high regio- and stereoselectivity. In this review, an insight into the most relevant advances on sustainable Diels–Alder reactions since 2010 is provided. Various environmentally benign solvent systems are discussed, namely bio-based derived solvents (such as glycerol and gluconic acid), polyethylene glycol, deep eutectic solvents, supercritical carbon dioxide, water and water-based aqueous systems. Issues such as method’s scope, efficiency, selectivity and reaction mechanism, as well as sustainability, advantages and limitations of these reaction media, are addressed.

The Diagnostic Value of Conventional MRI and CT Features in the Identification of the IDH1-Mutant and 1p/19q Co-Deletion in WHO Grade II Gliomas

RATIONALE AND OBJECTIVES

The classification of patients based on pathology and molecular features is important for improving WHO grade II glioma patient prognosis, especially for the initially diagnosed patients. Less invasive and more convenient methods for the prediction of the pathological type and gene status are desired.

MATERIALS AND METHODS

This study investigates the ability to use conventional magnetic resonance imaging (MRI) and computed tomography (CT) features for determining the Isocitrate Dehydrogenase (IDH)-mutant and 1p/19q-codeletion status, through a retrospective review of information obtained from 189 WHO grade II glioma patients. Diffuse astrocytoma (IDH-mutant), Diffuse astrocytoma (IDH- wildtype) and Oligodendroglioma (IDH-mutant and 1p/19q co-deletion) were included in this cohort. All patients were divided into IDH-mutant group and IDH-wildtype group according to the IDH R132H mutation status. Moreover, all patients were divided into 1p/19q co-deletion group and 1p/19q non-codeletion group according to the 1p and 19q chromosome status. Patients underwent pre-operative CT and MRI scans, followed by operation and histopathological analyses, including immunohistochemistry and polymerase chain reaction analysis for IDH mutants, and fluorescence capillary electrophoresis analysis for the 1p/19q co-deletion. The χ² test, logistical regression and receiver operating characteristic curve analysis were conducted for statistical analysis.

RESULTS

IDH-mutant group patients exhibited a higher calcification frequency (25.2% vs 2.4%, p = 0.006) and lower frequency of T1 enhancement (20.4% vs 38.1%, p = 0.028) comparing patients in IDH-wildtype group, while 1p/19q co-deletion group patients exhibited a higher calcification frequency (46.67% vs 2.6%, p < 0.001) and lower homogenous signal frequency in T2WI (12.0% vs 31.6%, p = 0.014), sharp lesion margins (14.7% vs 43.0%, p = 0.010), T2/fluid attenuated inversion recovery mismatch signs (22.7% vs 50.9%, p = 0.001), and subventricular zone involvement (64.0% vs 15.8%, p = 0.021) comparing patients in 1p/19q non-codeletion group. According to the results of receiver operating characteristic analysis, these features were observed to have certain diagnostic abilities, especially with regard to combination parameters, which had a high diagnostic capability, with an area under the curve of 0.848.

CONCLUSION

Conventional MRI and CT features, which still represent the most convenient and widely used predictive method, might be a promising noninvasive predictor for differentiating between varied WHO grade II gliomas. Patients with calcification and T1 nonenhancement are more likely to be IDH-mutant. Moreover, patients with noncalcification, homogenous signal, sharp lesion margins, subventricular zone involvement on T2 and T2/fluid attenuated inversion recovery mismatch signs are more likely to be 1p/19q non-codeletion.

Conventional Magnetic Resonance Features for Predicting 1p19q Codeletion Status of World Health Organization Grade II and III Diffuse Gliomas

PURPOSE

The conventional magnetic resonance features of World Health Organization (WHO) grade II and III diffuse gliomas in relation to chromosome 1p and 19q deletions (1p19q codeletion) were analyzed.

METHODS

We identified 147 cases of WHO grade II and III diffuse gliomas (1p/19q codeletion, 36 cases; no 1p/19q codeletion, 111 cases). χ Test and univariate and multivariate binary logistic regression analyses were conducted to evaluate the association between the imaging features and 1p19q codeletion status of WHO grade II and III diffuse gliomas in the discovery group, including the WHO grade II and III subgroups.

RESULTS

(1) In the entire population, multivariate regression demonstrated that proportion contrast-enhanced tumor (>5% vs ≤5%; odds ratio [OR], 0.169; P = 0.009), enhancing margin (poorly vs well defined; OR, 12.435; P = 0.002), and hemorrhage (yes vs no; OR, 21.082; P < 0.001) were associated with a higher incidence of 1p19q codeletion status. The nomogram showed good discrimination (area under the curve [AUC], 0.803) and calibration. (2) For grade II tumors, subgroup analysis found that enhancing margin (poorly vs well defined; OR, 0.308; P = 0.007) and subventricular zone (presence vs absence-; OR, 0.137; P < 0.001) were associated with a higher incidence of 1p19q codeletion status (AUC, 0.779). (3) For grade III tumors, subgroup analysis found that age (≥40 years vs <40 years; OR, 5.977; P = 0.03) and hemorrhage (yes vs no; OR, 18.051; P < 0.001) were associated with a higher incidence of 1p19q codeletion status (AUC, 0.816).

CONCLUSIONS

Conventional magnetic resonance features can be conveniently used to facilitate the preoperative prediction of 1p19q codeletion status of WHO grade II and III diffuse gliomas. Decision curve analysis demonstrated that the nomogram was clinically useful.

Domino ring-opening cyclization (DROC) of activated aziridines and epoxides with nitrones via dual-catalysis “on water”

A simple and green approach for the synthesis of non-racemic 1,2,4-oxadiazinanes and 1,4,2-dioxazinanes with excellent yields (up to 99%) and stereoselectivity (de/ee > 99%) in water has been described.

Organic synthesis reactions on-water at the organic–liquid water interface

Organic synthesis on-water has shown surprising successful synthetic methods. This review discusses the array of chemistry, which has been adapted with this methodology.

Organocatalyzed enantioselective Michael addition/cyclization cascade reaction of 3-isothiocyanato oxindoles with arylidene malonates

Both enantiomers of functionalized 3,2′-pyrrolidinyl spirooxindoles were obtainedviaa Michael-cyclization cascade reaction using pseudoenantiomeric cinchona alkaloid derived thiourea based bifunctional catalysts.