N. V. Kulik

Antimicrobial activity of pyrimidinophanes with thiocytosine and uracil moieties.

Reactions of pyrimidinophanes with two 6-methylthiocytosine and one 5(6)-alkyluracil moieties bridged with each other by polymethylene spacers with methyl or nonyl p-toluenesulfonate, p-toluenesulfonic acid, methanesulfonate and trifluorosulfonate afforded amphiphilic macrocyclic bis-p-toluene-, methane- and trifluorosulfonates. Despite the presence of several reaction centers in the initial pyrimidinophane molecules, protonation and methylation occurred only at the N(1) atom (with quaternization) of the 6-methylthiocytosine moieties. The bacteriostatic and fungistatic activity of the products was estimated. Macrocyclic tosylates exhibit a remarkable selectivity towards Staphylococcus aureus, with MIC values comparable with a reference drug. Bacteriostatic activity of the amphiphilic pyrimidinophanes depends on the size of the macrocycles, and the highest activity corresponds to definite lengths of polymethylene bridges. Besides, the antimicrobial activity of the screened pyrimidine derivatives depends on their topology. While macrocyclic tosylates are more active against bacteria than against fungi, acyclic tosylate with the same structural fragments shows a dramatical decrease of MIC towards mold and yeast with respect to the corresponding macrocycle. It is found that macrocyclic and acyclic tosylates in high dilutions decrease the extracellular lipase activity.

Macrocyclic and acyclic 1,3-bis[5-(trialkylammonio)pentyl]-5(6)-substituted uracil dibromides: synthesis, antimicrobial properties, and the structure—activity relationship

A series of acyclic onium uracil derivatives was synthesized, including 1,3-bis[5-(alkyldiethylammonio)pentyl]-5(6)-substituted uracil dibromides and isostructural macrocyclic compounds (isomeric cis- and trans-pyrimidinophanes bearing onium groups in the decamethylene chains). The compounds were found to exhibit considerable bacteriostatic and fungistatic activity. The onium uracil derivatives were found to make a specific contribution to the antimicrobial action: the bacteriostatic and fungistatic activities of the compounds are determined by their topology, the nature of a substituent at atom C(5) of the uracil ring and a substituent in the onium group. The mechanism of antimicrobial action and cytotoxicity of uracil onium derivatives were studied.

Synthesis and antimicrobial and antifungal activity of derivatives of the diterpenoid isosteviol and the glycoside steviolbioside containing onium nitrogen atoms

Previously unknown derivatives of the diterpenoid isosteviol and the glycoside steviobioside containing onium nitrogen atoms were synthesized. The antimicrobial and antifungal activities of these compounds were studied.

Synthesis and antibacterial and antifungal properties of some phosphorus-containing 1,2-dihydroxynaphthalenes

A series of phosphorus-containing 1,2-dihydroxynaphthalenes have been obtained via the reaction of 1,2-naphthoquinone derivatives with tri(n-butyl)- or triphenylphosphine followed by treatment of the intermediate phosphobetaines with various acids. The antimicrobial activity of the synthesized compounds has been studied and the structure—activity relationship established, which gives grounds for the search for new biologically active compounds in this direction.

Synthesis and antimicrobial and toxic properties of novel 1,3-bis(alkyl)-6-methyluracil derivatives containing 1,2,3- and 1,2,4-triazolium fragments

The antimicrobial activity and cytotoxicity of novel 1,3-bis(alkyl)-6-methyluracil derivatives containing 1,2,3- and 1,2,4-triazolium fragments in alkyl chains have been studied. The compounds have been tested for the antimicrobial activity toward some gram-positive and gram-negative bacteria and fungal cultures. The cytotoxic action has been estimated toward mammalian cells. It has been found that the basic structural factor that affects the antimicrobial activity is the nature of alkyl radicals at triazole fragments.

Synthesis and antimicrobial activity of pyrimidinophanes with two uracil units and bridging nitrogen atoms

A series of pyrimidinophanes containing two uracil units and nitrogen atoms in bridging polymethylene chains –(CH2)nN(Et)(CH2)m– (n, m = 5, 6) have been synthesized. The uracil moieties are represented by 6-methyl-, 5-decyl-6-methyl-, and 5-fluorouracils. Quaternization of the bridging N atom with ethylbromide or n-decylbromide yielded amphiphilic pyrimidinophanes, which were evaluated for their antibacterial and antifungal activity in terms of minimal inhibiting concentration (MIC) against Gram-positive and Gram-negative bacteria and fungi. It has been found that MICs of the amphiphilic pyrimidinophanes decrease with increasing lipophilicity of the alkyl substituents at the bridging N atoms and with increasing polymethylene N(pyr)–N chain length (in some cases MIC against Staphylococcus aureus is below 1 ìg/mL). The MICs increase dramatically upon introduction of lipophilic n-decyl substituents at C(5) atoms of the uracil moiety. The results can be used in the search for new highly effective antimicrobial agents.

Synthesis and antimicrobial activity of several bis-quaternized ammonium derivatives of the diterpenoid isosteviol

Previously unreported bis-quaternized ammonium derivatives of the diterpenoid isosteviol (16-oxo-entbeyeran-19-oic acid) were synthesized. The compound in which the two quaternized N atoms were joined by a dodecamethylene spacer had the greatest antimicrobial activity and was comparable in activity with ciprofloxacin and clotrimazole.

Synthesis and antimicrobial activity of pyrimidinophanes containing a uracil moiety and a bridging sulfur atom

Pyrimidinophanes containing one 5(6)-alkylsubstituted uracil moiety and a 10-or 12-methylene bridge including a sulfur atom were synthesized. The bridging S atoms of the macrocycles were converted to sulfonium groups by interaction with para-toluenesulfonate methyl or nonyl esters. The resulting amphiphilic pyrimidinophanes were tested for bacteriostatic and fungistatic activity against Gram-positive and Gram-negative bacteria and fungi. Amphiphilic pyrimidinophanes with 5-decyl-6-methyluracil moieties had high levels of bacteriostatic activity against Gram-positive bacteria. The minimum inhibitory concentration of the macrocycle containing a methyl group in the sulfonium grouping against Staphylococcus aureus was 0.75 !g/ml. These data are of value in seeking new highly effective antimicrobial agents.

Isatin Derivatives Containing Sterically Hindered Phenolic Fragment and Water-Soluble Acyl Hydrazones on Their Basis: Synthesis and Antimicrobial Activity

Condensation reactions of isatin derivatives with 3,5-di(tert-butyl)-4-hydroxybenzyl acetate and the Girard’s reagent T has afforded a series of novel water-soluble isatin-3-acyl hydrazones containing a sterically hindered phenolic fragment in position 1 of the heterocycle; antimicrobial activity of the products has been estimated. It has been shown that the isatin derivatives with bromine or methoxy substituent in the benzo fragment as well as the acyl hydrazones containing 5-methyl or 5-ethyl group are the most active against Staphylococcus aureus and Bacillus cereus.

Synthesis and antimicrobial activity evaluation of some novel water-soluble isatin-3-acylhydrazones

By acid-catalyzed reaction of substituted isatins with Girard’s reagent T, new water-soluble isatin-3-acylhydrazones were obtained with high yields. Their antimicrobial activity was evaluated. Selective activity against Gram-positive bacteria (S. aureus 209p and B. cereus 8035) and yeast-like fungus Candida albicans 855–653 along with low hematoxicity was established.Graphical abstract