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We studied the effects of quaternary bis-phosphonium and bis-ammonium salts of pyridoxine with lipophilic substituents on the survival and morphology of Staphylococcus aureus cells. We found that, while originating from the same base, they exhibit considerably different antimicrobial mechanisms. In the presence of Ca(2+) ions the MIC and MBC values of ammonium salt increased 100-fold, suggesting that Ca(2+) ions can successfully impede the membrane Ca(2+) ions exchange required for ammonium salt incorporation. In contrast, in the presence of quaternary phosphonium salt, the artificial capsular-like material was formed around the cells and the filamentous and chain-like growth of the cells was observed suggesting the disruption of the cell division mechanisms. Altogether, both pyridoxine derivatives successfully inhibited the growth of gram-positive bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis) and Escherichia coli considerably, while demonstrated nearly no effect against Klebsiella pneumoniae and Pseudomonas aeruginosa. We suggest that due to their effects on distinct and likely complementary targets the derivatives of pyridoxine represent potentially perspective antibacterials with complicated adaptation and thus with lower risk of drug resistance development.

Base-Promoted Formationofa nA nnelated Pyrrolo-1,4-oxazine Ensemblefrom 1H-pyrrol-2-ylmethanol and Propargyl Chloride:ATheoretical and Experimental Study What prompted you to investigate this topic/problem?The Irkutsk School of Organic Chemistry has rich and broad experience in building and functionalizing pyrrole systems in ac onvenient and universal fashion. The work presented is ac ontinuation of as eries of investigations to activate several reactive centers of pyrrole with the aim to synthesize previously unknown compounds with promising properties, such as drugs and precursors of materials with specific characteristics.Invited for this month'sc over is the group of Prof. Dr.N adezhda M. Vitkovskaya at Irkutsk State University and the group of Dr.A ndrey V. Ivanova tt he A. E. Favorsky Irkutsk Institute of Chemistry,R ussian Federation.The image shows that three different pyrrole derivatives can be obtained from the same starting reagents. The reaction is easily controlled by the ratio of the reagents, the amount of alkali, and the degree of dilution.T he three strings of the balalaika (a Russianf olk instrument) that represent these parametersc an produce melodies from the same notes symbolizing the reagents. The sheets with quantum-chemical calculations under the musical notebooks ymbolize thatt he experimental work is based on the theoretical investigations. Read the full text of the article at

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