Department of Chemistry and Fujian Provincial Key Laboratory of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, PR China.
Published: August 2021
AI Article Synopsis
Article Abstract
This article describes the full details of our synthetic efforts toward the enantioselective total synthesis of the complex alkaloid methoxystemofoline. The enantioselective construction of the tetracyclic core features: (1) the Keck allylation at the -α bridgehead carbon to forge the tetrasubstituted stereocenter; (2) an olefin cross-metathesis reaction for the side-chain elongation that is amenable for the synthesis of congeners and analogues; and (3) a regioselective aldol addition reaction with methyl pyruvate that ensured the subsequent regioselective cyclization reaction to construct the fourth ring. Overman's method was employed to install the 5-(alkoxyalky1idene)-3-methyl-tetronate moiety. In the last step, a nonstereoselective reaction resulted in the formation of both the proposed structure of methoxystemofoline and its -stereoisomer, the natural product (revised structure), in a 1:1 ratio. We suggest to rename the natural product as isomethoxystemofoline, and report for the first time the complete H NMR data for this natural product.
Clinical trials are the most rigorous scientific and regulated method to investigate the safety and efficacy of vaccines or drugs in pre-licensure stage. Clinical trial design and implementation are complex, time-consuming and involves close engagement with country's regulatory authority, clinical trial sites, investigators, and the healthcare system. Over the past few decades, a significant number of clinical trials have been conducted in low- and middle-income countries (LMICs), particularly in resource-limited settings.
Objectives: To explore the effect and the probable mechanisms of JLD in the treatment of type 2 diabetes mellitus (T2DM) - associated cognitive impairment (TDACI).
Methods: The effect of JLD in combating TDACI was assessed in T2DM model mice by conducting Morris water maze (MWM) behaviour testing. Active components and their putative targets, as well as TDACI-related targets, were collected from public databases.
Acute myeloid leukemia (AML), which is most common in adults, is a challenging hematological malignancy. The occurrence and the progression of AML are often accompanied by various gene fusions and/or mutations. Herein, we report the first case of a fusion transcript with a translocation of (1;12)(q25;p13) in AML progressed from myelodysplastic syndrome (MDS) combined with an -ITD (internal tandem duplication) mutation.
serovar Rissen ( Rissen) is an emerging causative agent of foodborne diseases. The current emergence of antibiotic resistance makes necessary alternative therapeutic strategies. In this study, we investigated the potential of a phage-resistant strain of Rissen (R) as a tool for developing an effective lipopolysaccharide (LPS)-based vaccine.
