10.1016/j.bmcl.2010.10.122
The research focuses on the development of novel gratisin (GR) derivatives with high antimicrobial activity and low hemolytic activity. The study investigates the impact of substituting each constituent amino acid residue of GR with alanine (Ala) and identifies that modifications at the Pro5,5 residues significantly influence both antibiotic and hemolytic activities. Specifically, replacing Pro residues at positions 5 and 5 with cationic amino acids like lysine (Lys) and arginine (Arg) enhances antibiotic activity while reducing toxicity to human blood cells. The researchers synthesized various GR analogues using Boc-solid phase peptide synthesis and characterized their structures and biological activities. Key chemicals involved in the synthesis include Boc-amino acids, BOP (benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate), HOBt (1-hydroxybenzotriazole), NEt3 (triethylamine), and thioanisole. The study also utilized reagents such as acetic acid and trifluoroacetic acid (TFA) for cyclization and deprotection steps. The findings suggest that these modified GR derivatives could serve as potential drug candidates to combat multidrug-resistant bacteria while minimizing adverse effects on human cells.
10.1002/adsc.200800291
Feng Wang, Hua Fu, Yuyang Jiang, and Yufen Zhao presents a green and practical method for synthesizing N-sulfonyltriazoles using a copper-catalyzed cycloaddition reaction. The study focuses on the Huisgen [3+2] cycloaddition of water-insoluble sulfonyl azides with alkynes in water at room temperature, catalyzed by an inexpensive CuX/PhSMe system. The addition of thioanisole as a ligand significantly inhibits the cleavage of the N1–N2 bond in the 5-cuprated N-sulfonyltriazole intermediates, thereby improving the yields of the desired N-sulfonyltriazoles. The optimized conditions involve using 10 mol% CuBr and 20 mol% thioanisole relative to sulfonyl azide in water, resulting in high yields and excellent functional group tolerance. The method is advantageous due to its low cost, high yield, high regioselectivity, use of water as a medium, room temperature operation, and ease of work-up. The findings suggest that this method has potential for practical applications in various research fields.
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