ABSTRACT
This study introduces a novel approach involving XB-mediated cross-coupling of α-trifluoromethylated alkyl bromides with coumarins and quinolinones under visible light irradiation. Both density functional theory (DFT) calculations and experimental studies converge to suggest that the noncovalent interaction between alkyl bromides and DMAP, intensified by the α-trifluoromethyl group, plays a pivotal role in facilitating this chemoselective reaction.
ABSTRACT
Polyfluoroaromatic compounds play crucial roles in medicinal and material science. However, the synthesis of alkylated polyfluoroarenes has been relatively underdeveloped. In this study, we devised a novel decarboxylative coupling reaction between aliphatic N-hydroxyphthalimide esters and polyfluorostyrene, leveraging the photochemical activity of electron donor-acceptor (EDA) complexes. This method offers simple reaction conditions, a broad substrate scope, and excellent functional group tolerance. Furthermore, we have demonstrated the practicality of this protocol through late-stage polyfluoroaryl modification of biologically active molecules using readily available carboxylic acids as starting materials, thus providing an important supplement to the current toolbox for accessing alkylated polyfluoroaryl motifs.
ABSTRACT
<p><b>OBJECTIVE</b>In order to evaluate the safety and immunogenicity of group A + C meningococcal polysaccharide vaccine, a controlled field trial was performed among children at 6-24 months and 5-13 years old in Longsheng county, Guangxi Zhuang Autonomous Region.</p><p><b>METHODS</b>More than 600 children were selected in this trial. 428 children, aged 6-24 month-old and 5-13 year-old were involved in two experimental groups and were inoculated 100 microg of group A + C meningococcal polysaccharide vaccine. 103 children in positive control group were inoculated 50 microg of group A meningococcal polysaccharide vaccine while 94 children in negative control group were inoculated 30 microg of Typhoid Vi polysaccharide vaccine. Both systemic and local reactions were observed in each group at 6 h,24 h,48 h and 72 h after inoculation. Blood samples were collected in all children before and at 1 month after inoculation. Additionally, at least 50 blood samples were taken in each experimental group at 6 and 12 months after inoculation. Serum bactericidal antibody was tested by micro bactericidal test.</p><p><b>RESULTS</b>Both systemic and local reactions were mild in two experimental groups with only 3 children (0.7%) had > or = 37. 6 degrees C fever, 4 children (0.9%) appeared mild areola but all adverse reaction disappeared within 48 hours. In 5-13 year-old experimental group, the rates for four-fold increase of bactericidal antibody were 96.59% and 92.15% to group A and group C meningococcus respectively at 1 month after inoculation, and remained 90.91% and 90.08% at 12 months after inoculation.</p><p><b>CONCLUSION</b>Group A + C meningococal polysaccharide vaccine was safe and having good immunogenicity among Chinese children.</p>
