Lewis Acid-Catalyzed Annulations of Geminally Disubstituted Cyclopropanes with Aldehydes or 1,3,5-Triazinanes

Under the catalysis of simple Lewis acid catalysts, 2-(1-aroylcyclopropyl)malonates demonstrated unique reactivities in annulation reactions with aryl/alkyl aldehydes, paraformaldehyde, and 1,3,5-triazinanes. Three types of structurally diverse cyclic products that are otherwise not easy to obtain were generated in moderate to good yields and excellent diastereoselectivities. Possible reaction pathways leading to these products were proposed on the basis of the results of control experiments.

Catalytic enantioselective desymmetrization of meso-aziridines

As a type of readily available small strained-ring heterocycle, meso-aziridines may undergo catalytic desymmetrizing transformations to empower the rapid construction of diverse nitrogen-containing structures bearing contiguous stereocenters, which have great relevance in natural product synthesis, drug development and the design and synthesis of chiral catalysts/ligands for asymmetric catalysis. This review outlines the advances achieved in the catalytic asymmetric desymmetrization of meso aziridines and highlights some promising avenues for further work in this realm.

Synthesis of chiral β-substituted γ-amino-butyric acid derivatives via enantioconvergent ring opening of racemic 2-(hetero)aryl aziridines with ketene silyl acetals

Lewis acid-catalyzed enantioconvergent ring opening of racemic 2-(hetero)aryl-N-sulfonyl aziridines with ketene silyl acetals is developed.

Lanthanide-Catalyzed Tandem Addition of Amines to Cyanoalkenes: Synthesis of Cyclic Amidines

A tandem insertion of aliphatic nitriles and unactivated alkenes to the N-H bond of secondary aliphatic amines catalyzed by simple trialkyl rare-earth metal complexes was disclosed. This reaction provides a highly atom-economic and stereoselective way to a range of cyclic amidines under mild reaction conditions.

Urinary complement proteins and risk of end-stage renal disease: quantitative urinary proteomics in patients with type 2 diabetes and biopsy-proven diabetic nephropathy

PURPOSE

To investigate the association between urinary complement proteins and renal outcome in biopsy-proven diabetic nephropathy (DN).

METHODS

Untargeted proteomic and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional analyses and targeted proteomic analysis using parallel reaction-monitoring (PRM)-mass spectrometry was performed to determine the abundance of urinary complement proteins in healthy controls, type 2 diabetes mellitus (T2DM) patients, and patients with T2DM and biopsy-proven DN. The abundance of each urinary complement protein was individually included in Cox proportional hazards models for predicting progression to end-stage renal disease (ESRD).

RESULTS

Untargeted proteomic and functional analysis using the KEGG showed that differentially expressed urinary proteins were primarily associated with the complement and coagulation cascades. Subsequent urinary complement proteins quantification using PRM showed that urinary abundances of C3, C9, and complement factor H (CFAH) correlated negatively with annual estimated glomerular filtration rate (eGFR) decline, while urinary abundances of C5, decay-accelerating factor (DAF), and CD59 correlated positively with annual rate of eGFR decline. Furthermore, higher urinary abundance of CFAH and lower urinary abundance of DAF were independently associated with greater risk of progression to ESRD. Urinary abundance of CFAH and DAF had a larger area under the curve (AUC) than that of eGFR, proteinuria, or any pathological parameter. Moreover, the model that included CFAH or DAF had a larger AUC than that with only clinical or pathological parameters.

CONCLUSION

Urinary abundance of complement proteins was significantly associated with ESRD in patients with T2DM and biopsy-proven DN, indicating that therapeutically targeting the complement pathway may alleviate progression of DN.

Catalytic Asymmetric [3 + 2] Annulation of Hantzsch Esters with Racemic N-Sulfonylaziridines

Hantzsch esters (HEs) served as two-carbon partners in a copper(I)-catalyzed enantioselective [3 + 2] annulation with racemic 2-(hetero)aryl-N-sulfonyl aziridines via kinetic resolution to provide pyrrolo[2,3-b]tetrahydropyridines containing multiple contiguous stereogenic centers including all-carbon quaternary centers in excellent yields and enantiopurities and moderate-to-excellent diastereoselectivities. Mainly dependent upon the structures of the aziridines, a competitive hydrogenolysis process with HEs as the hydrogen source was also observed in some cases.

Associations between WNT signaling pathway-related gene polymorphisms and risks of osteoporosis development in Chinese postmenopausal women: a case-control study

BACKGROUND

The WNT signaling pathway is involved in the regulation of bone homeostasis, and the effect of WNT signaling pathway-related gene (WNT16 and LRP5) polymorphisms on osteoporosis risk among Chinese postmenopausal women is still unknown. Hence, we performed a case-control study to assess the association of WNT signaling pathway-related gene polymorphisms and osteoporosis risk.

METHODS

A total of 1026 women (515 osteoporosis patients and 511 controls) of postmenopausal age who were randomly sampled from Xi'an 630 Hospital (Shaanxi Province, China) were involved in this study. Seven genetic polymorphisms in WNT16 (rs3779381, rs3801387, rs917727 and rs7776725) and LRP5 (rs2291467, rs11228240 and rs12272917) were selected and genotyped using the Agena MassARRAY iPLEX system. The association of the genetic polymorphisms and osteoporosis risk was assessed by odds ratios and 95% confidence intervals. The multifactor dimensionality reduction (MDR) method was conducted to analyze single nucleotide polymorphism (SNP)-SNP interaction.

RESULTS

We found that LRP5 polymorphisms (rs2291467, rs11228240 and rs12272917) were significantly associated with a decreased risk of osteoporosis in homozygote, recessive and additive models (p < 0.05). Stratification analysis showed that LRP5 polymorphisms (rs2291467, rs11228240 and rs12272917) significantly decreased the osteoporosis risk in the subgroup of body mass index (BMI) ≤ 24 (p < 0.05) and that individuals carrying a heterozygote genotype of WNT16 polymorphisms (rs3779381, rs3801387, rs917727 and rs7776725) had a higher osteoporosis risk in the subgroup of BMI > 24 (p < 0.05). Two haplotypes (haplotype 1: rs3779381, rs3801387, rs917727 and rs7776725; haplotype 2: rs2291467 and rs11228240) were observed, yet only T_rs2291467T_rs11228240 and C_rs2291467C_rs11228240 had a strong association with a decreased risk of osteoporosis (p < 0.05). Additionally, MDR analysis revealed that LRP5 rs2291467 was the best model in single-locus MDR analysis. A seven-locus model including rs3779381-AG, rs7776725-TC, rs3801387-GA and rs917727-TC in WNT16 and rs11228240-CC, rs12272917-TC and rs2291467-CC in LRP5 was the best model in multiple-loci MDR analysis (p < 0.001). These two best models were the most significantly associated with osteoporosis risk.

CONCLUSIONS

Our findings suggested that WNT16 and LRP5 genetic polymorphisms are associated with osteoporosis risk among Chinese postmenopausal women.

Catalytic Asymmetric Transformations of Racemic Aziridines

The catalytic asymmetric ring-opening transformations of aziridines represent an important strategy for the construction of various chiral nitrogen-containing molecular architectures. This short review covers the progress achieved in the catalytic asymmetric transformation of racemic aziridines, focusing on the catalytic strategies employed for each different type of such aziridines.

1 Introduction

2 Reaction of Racemic 2-Vinylaziridines

3 Reaction of Racemic 2-Alkylaziridines

3.1 Regiodivergent Parallel Kinetic Resolution

3.2 Kinetic Resolution

4 Reaction of Racemic 2-(Hetero)arylaziridines

4.1 Kinetic Resolution

4.2 Enantioconvergent Transformation

5 Reaction of Racemic Donor–Acceptor-Type Aziridines

6 Conclusion and Outlook

Ti n+1C n MXenes with fully saturated and thermally stable Cl terminations

MXenes are a rapidly growing family of 2D materials that exhibit a highly versatile structure and composition, allowing for significant tuning of the materials properties. These properties are, however, ultimately limited by the surface terminations, which are typically a mixture of species, including F and O that are inherent to the MXene processing. Other and robust terminations are lacking. Here, we apply high-resolution scanning transmission electron microscopy (STEM), corresponding image simulations and first-principles calculations to investigate the surface terminations on MXenes synthesized from MAX phases through Lewis acidic melts. The results show that atomic Cl terminates the synthesized MXenes, with mere residual presence of other termination species. Furthermore, in situ STEM-electron energy loss spectroscopy (EELS) heating experiments show that the Cl terminations are stable up to 750 °C. Thus, we present an attractive new termination that widely expands the MXenes' functionalization space and enables new applications.

Synthesis of 2-Aminophosphates via SN2-Type Ring Openings of Aziridines with Organophosphoric Acids

The synthesis of 2-aminophosphates is achieved by a S_N2-type ring opening reaction of various N-protected or free aziridines with phosphoric acids in a regiospecific and/or enantiospecific way. A one-pot, two-step procedure is also developed enabling direct access to 2-aminophosphates from olefins without isolation of the aziridine intermediates.

Comparative expression profile of microRNAs and piRNAs in three ruminant species testes using next-generation sequencing

microRNA (miRNA) and piwi-interacting RNA (piRNA) are two classes small non-coding regulatory RNAs that play crucial roles in multiple biological processes such as spermatogenesis. However, there are no published studies on conjoint analysis of miRNA and piRNA profiles among cattle, yak and their interspecies (the dzo) using sequencing technology. Next-generation sequencing technology was used to profile miRNAs and piRNAs among those three ruminants to elucidate their functions. A total of 119, 14 and six differentially expressed miRNAs were obtained in cattle vs. dzo, cattle vs. yak and yak vs. dzo comparison groups, while there were 873, 1,065 and 1,158 differentially expressed piRNAs in those three comparison groups. The expression of three miRNAs was validated in the three ruminants, and the results suggested that the miRNA expression profiles data could represent actual miRNA expression levels. Moreover, the putative targets of differentially expressed miRNAs were predicted by their own genome, it is worth to note that both the cattle and yak genome were used for dzo, then the targets were subjected to GO enrichment and KEGG pathway analysis, revealing the likely roles for these differentially expressed miRNAs in spermatogenesis. In conclusion, this study provided a useful resource for further elucidation of the miRNAs and piRNAs regulatory roles in spermatogenesis. It may also facilitate the development of therapeutic strategies for dzo reproduction research.

Lewis acid-catalyzed enantiospecific [3 + 2] annulations of γ-butyrolactone fused cyclopropanes with aromatic aldehydes: synthesis of chiral furanolignans

An enantiospecific [3 + 2] annulation of γ-butyrolactone fused cyclopropanes with aromatic aldehydes was realized to construct chiral furanolignans.

Half-sandwich chiral rare-earth metal complexes with linked tridentate amido-indenyl ligand: synthesis, characterization, and catalytic properties for intramolecular hydroamination

Novel rare-earth metal complexes featuring a tridentate carbon-linked amido-indenyl ligand have been synthesized and used to catalyze the intramolecular olefin hydroamination.

Asymmetric α-amination of 3-substituted oxindoles using chiral bifunctional phosphine catalysts

A highly enantioselective α-amination of 3-substituted oxindoles with azodicarboxylates catalyzed by amino acids-derived chiral phosphine catalysts is reported. The corresponding products containing a tetrasubstituted carbon center attached to a nitrogen atom at the C-3 position of the oxindole were obtained in high yields and with up to 98% ee.

[3 + 2]-Annulations of N-alkyl-3-substituted indoles with quinone monoketals catalysed by Brønsted acids

An organocatalytic dearomative [3 + 2]-annulation of 3-alkylindoles and quinone monoketals provided benzofuro[2,3-b]indolines, while the reaction with 3-phenylindole leads to 2,3-diarylindoles in moderate yields.

Effects of corn and soybean meal types on rumen fermentation, nitrogen metabolism and productivity in dairy cows

Twelve multiparous Holstein dairy cows in mid-lactation were selected for a replicated 4×4 Latin square design with a 2 ×2 factorial arrangement to investigate the effects of corn and soybean meal (SBM) types on rumen fermentation, N metabolism and lactation performance in dairy cows. Two types of corn (dry ground [DGC] and steam-flaked corn [SFC]) and two types of SBM (solvent-extracted and heat-treated SBM) with different ruminal degradation rates and extents were used to formulate four diets with the same basal ingredients. Each period lasted for 21 days, including 14 d for adaptation and 7 d for sample collection. Cows receiving SFC had a lower dry matter (DM) and total N intake than those fed DGC. However, the milk yield and milk protein yield were not influenced by the corn type, resulting in higher feed and N utilization efficiency in SFC-fed cows than those receiving DGC. Ruminal acetate concentrations was greater and total volatile fatty acids concentrations tended to be greater for cows receiving DGC relative to cows fed SFC, but milk fat content was not influenced by corn type. The SFC-fed cows had lower ruminal ammonia-N, less urea N in their blood and milk, and lower fecal N excretion than those on DGC. Compared with solvent-extracted SBM-fed cows, cows receiving heat-treated SBM had lower microbial protein yield in the rumen, but similar total tract apparent nutrient digestibility, N metabolism measurements, and productivity. Excessive supply of metabolizable protein in all diets may have caused the lack of difference in lactation performance between SBM types. Results of the present study indicated that increasing the energy degradability in the rumen could improve feed efficiency, and reduce environmental pollution.