The configuration of the anomeric glycosidic linkages is crucial for maintaining the biological functions and activities of carbohydrate molecules. However, their stereochemistry control in glycosylation represents one of the most challenging tasks in carbohydrate chemistry. In this report, the easily accessible 2-diphenylphosphinoyl-acetyl (DPPA) group was developed as a highly stereodirecting group for catalytic glycosylation via hydrogen-bond mediated delivery of the alcoholic acceptors. TMSOTf-catalyzed glycosylation with DPPA-installed glycosyl imidate donors displayed excellent β-selectivities and broad substrate scope, particularly practical to synthesize the challenging β-configured 2-deoxy and 2-azido-2-deoxy glycosides from poor acceptors suffering from electron-deficiency, steric hindrance, and structural rigidity. Chemoselective removal of the DPPA group could be readily achieved under the mild catalysis of Ni(OTf) 2 without affecting acid-or base-labile functional groups, facilitating a rapid conversion to biologically important molecules such as uronic acids and 2,6-deoxy glycosides. The application of this DPPA-directed glycosylation was further highlighted in the complex synthesis toward saponin dioscin using 2,4-O-glycosylated donor in a convergent manner.
The anomeric configuration can greatly affect the biological functions and activities of carbohydrates. Herein, we report that N‐phenyltrifluoroacetimidoyl (PTFAI), a well‐known leaving group for catalytic glycosylation, can act as a stereodirecting group for the challenging 1,2‐cis α‐glycosylation. Utilizing rapidly accessible 1,6‐di‐OPTFAI glycosyl donors, TMSOTf‐catalyzed glycosylation occurred with excellent α‐selectivity and broad substrate scope, and the remaining 6‐OPTFAI group can be cleaved chemoselectively. The remote participation of 6‐OPTFAI is supported by the first characterization of the crucial 1,6‐bridged bicyclic oxazepinium ion intermediates by low‐temperature NMR spectroscopy. These cations were found to be relatively stable and mainly responsible for the present stereoselectivities. Further application is highlighted in glycosylation reactions toward trisaccharide heparins as well as the convergent synthesis of chacotriose derivatives using a bulky 2,4‐di‐O‐glycosylated donor.
Schizophrenia is an unexplained, complex and serious mental illness. Blonanserin (BNS) is a new antipsychotic drug widely used in the treatment of schizophrenia. However, large-scale clinical studies have not been conducted in China. A multi-center, prospective, open-label, 12-week surveillance was carried out to evaluate the safety and effectiveness of BNS in patients with schizophrenia in China. Safety assessments included adverse drug reactions (ADRs), extrapyramidal symptoms (EPS), akathisia, concomitant medications for EPS by the end of treatment, and the changes in body weight from baseline by the end of treatment. The effectiveness was evaluated by the Brief Psychiatric Rating Scale (BPRS). From September 2018 to May 2020, of the 1,060 patients enrolled, 1,018 were included in the full analysis set (FAS) and safety set (SS), respectively. ADRs were developed in 205 patients among the included, the incidence being 20.1%. ADRs of EPS occurred in 169 patients, the incidence being 16.6%, ADRs of akathisia occurred in 90 patients, the incidence being 8.8%; concomitant therapeutic and prophylactic agents for EPS accounts for 19.2%; 4.0% of patients had a ≥7% increase in body weight from baseline at 12 weeks after initiating treatment. Using the last-observation-carried-forward (LOCF) method, the changes in total BPRS scores were −11.2 ± 10.17 (N = 1,018), −16.8 ± 12.69 (N = 1,018) and −20.6 ± 13.99 (N = 1,018) after 2/4, 6/8, or 12 weeks, respectively. 53.5% (545/1,018) patients showed response to blonanserin treatment in week 12. The post-marketing surveillance results of BNS demonstrates safety profile and effectiveness of the drug.
Anomeric stereocontrol is usually one of the major issues in the synthesis of complex carbohydrates, particularly those involving β‐configured 2,6‐dideoxyglycoside and d/l‐rhamnoside moieties. Herein, we report that 2‐(diphenylphosphinoyl)acetyl is highly effective as a remote stereodirecting group in the direct synthesis of these challenging β‐glycosides under mild conditions. A deoxy‐trisaccharide as a mimic of the sugar chain of landomycin E was prepared stereospecifically in high yield. The synthetic potential was also highlighted in the synthesis of Citrobacter freundii O‐antigens composed of a [→4)‐α‐d‐Manp‐(1→3)‐β‐d‐Rhap(1→4)‐β‐d‐Rhap‐(1→] repeating unit, wherein the convergent assembly up to a nonasaccharide was realized with a strongly β‐directing trisaccharide donor. Variable‐temperature NMR studies indicate the presence of intermolecular H‐bonding between the donor and the bulky acceptor as direct spectral evidence in support of the concept of hydrogen‐bond‐mediated aglycone delivery.
Background Schizophrenia (SCZ) is a severe mental illness with high heritability. This study aimed to explore the correlation between MAD1L1, TSNARE polymorphisms and SCZ susceptibility. Methods A total of 493 SCZ patients and 493 healthy controls were included. The genotypes of MAD1L1 and TSNARE polymorphisms were identified by Agena MassARRAY platform. Odds ratio (OR) and 95% confidence intervals (CIs) were tested via logistic regression analysis in multiple genetic models and different subgroups. Results We observed that AG genotype of rs1107592, AG genotype of rs4976976, and CA genotype of rs67756423 decreased the susceptibility to SCZ (p < 0.05). Age stratification analysis showed that the TC genotype of rs12666575, AG genotype of rs1107592, and AG genotype of rs4976976 decreased the risk of SCZ individuals older than 36 years (p < 0.05). In addition, the AG and AA genotype of rs4976976, the CA genotype of rs67756423 were associated with a lower risk of SCZ in males (p < 0.05). In females, the TT genotype of rs12666575 in recessive model, the AG and AA-AG genotype of rs1107592 in heterozygote and dominant model, could reduce the susceptibility to SCZ (p < 0.05). However, no significant association was found after Bonferroni correction. Conclusions Our results suggest that MAD1L1 and TSNARE genetic polymorphisms exert a protective role in the risk of SCZ. These findings provide evidence that MAD1L1 and TSNARE may serve as potential biomarkers of SCZ. However, a replication experiment in a cohort with large sample size are required to confirm our findings. Trial registration Not applicable.
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