Synthesis and antibacterial activity of bis-[2-hydroxy-3-(1,7,8,9,10-pentamethyl-3,5-dioxo-4-aza-tricyclo[5.2.1.02,6]dec-8-en-4-yloxy)-propyl]-dimethyl-ammonium chloride

Cobalt-Catalyzed Enantio- and Regioselective C(sp3 )-H Alkenylation of Thioamides

An enantioselective cobalt-catalyzed C(sp3 )-H alkenylation of thioamides with but-2-ynoate ester coupling partners employing thioamide directing groups is presented. The method is operationally simple and requires only mild reaction conditions, while providing alkenylated products as single regioisomers in excellent yields (up to 85 %) and high enantiomeric excess [up to 91 : 9 enantiomeric ratio (er), or up to >99 : 1 er after a single recrystallization]. Diverse downstream derivatizations of the products are demonstrated, delivering a range of enantioenriched constructs. Extensive computational studies using density functional theory provide insight into the detailed reaction mechanism, origin of enantiocontrol, and the unusual regioselectivity of the alkenylation reaction.

Synthesis, cytotoxicity and antimicrobial activity of thiourea derivatives incorporating 3-(trifluoromethyl)phenyl moiety

A total of 31 of thiourea derivatives was prepared reacting 3-(trifluoromethyl)aniline and commercial aliphatic and aromatic isothiocyanates. The yields varied from 35% to 82%. All compounds were evaluated in vitro for antimicrobial activity. Derivatives 3, 5, 6, 9, 15, 24 and 27 showed the highest inhibition against Gram-positive cocci (standard and hospital strains). The observed MIC values were in the range of 0.25-16 μg/ml. Inhibitory activity of thioureas 5 and 15 against topoisomerase IV isolated from Staphylococcus aureus was studied. Products 5 and 15 effectively inhibited the formation of biofilms of methicillin-resistant and standard strains of Staphylococcus epidermidis. Moreover, all obtained thioureas were evaluated for cytotoxicity and antiviral activity against a large panel of DNA and RNA viruses. Compounds 5, 6, 8-12, 15 resulted cytotoxic against MT-4 cells (CC50 ≤ 10 μM).

Synthesis, surface and antimicrobial properties of some quaternary ammonium homochiral camphor sulfonamides

A group of homochiral quaternary ammonium sulfonamides bearing hydrophobic camphor derived moieties were synthesized and characterized. The described synthetic procedure is quick and efficient. The novel quaternary ammonium bromides were tested as antimicrobial and antifungal agents. They exhibited strong antimicrobial and also antifungal activity, especially N-{2-[((1S, 4R)-7,7-dimethyl-2-oxobicyclo[2.2.1]heptan-1-yl)methylsulfonamido] ethyl}-N,N-dimethyltetradecan-1-aminium bromide 1c. The surface properties of prepared compounds were evaluated by surface tension measurements and critical micelle concentration (CMC) with surface tension at CMC (γCMC) was calculated.

Synthesis and antimicrobial properties of binaphthyl derived quaternary ammonium bromides

(S)-N-(2-(4,5-dihydro-3H-dinaphtho[2,1-c:1',2'-e]azepin-1-yl)ethyl)-N, N-dimethyl-N-dodecyl ammonium bromide (S)-1a and (S)-N-(2-(4,5-dihydro-3H-dinaphtho[2,1-c:1',2'-e]azepin-1-yl)ethyl)-N, N-dimethyl-N-tetradecylammonium bromide (S)-1b have been synthesized as optically active quaternary ammonium salts starting from 1,1'-binaphthyl-2,2'-diol. Their antimicrobial activity expressed as minimal inhibition concentration (MIC) was tested against Gram-positive human pathogenic bacteria S. Aureus, Gram-negative bacteria E. coli and human fungal pathogen C. Albicans.

Antimicrobial activity of [2-(methacryloyloxy)ethyl]trimethylammonium chloride against Candida spp

BACKGROUND

Candida-associated denture stomatitis is the most common manifestation of oral candidal infection, caused mainly by Candida albicans. Several authors have attempted to add antifungal agents or antiseptics to denture temporary soft lining materials or to denture acrylic resins, without relevant results. Therefore, the investigation of a quaternary ammonium functionalized compound [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MADQUAT), which copolymerizes with methacrylates and which could act as a fungal inhibitor, is of paramount importance.

AIMS

To evaluate the in vitro activity of MADQUAT against Candida species.

METHODS

Thirty-one Candida strains were used to determine the in vitro antifungal activity of this compound. The minimum inhibitory concentrations and minimum fungicidal concentrations of MADQUAT and nystatin were determined.

RESULTS

MADQUAT showed antifungal properties at concentrations of 6.25 to > 100mg/ml, and fungicidal activity between 25 and > 100mg/ml. The quantitative determinations of the fungistatic and fungicidal activity of MADQUAT showed fungistatic activity against all Candida albicans, Candida krusei and Candida parapsilosis strains, revealing fungicidal activity against some strains of the other species.

CONCLUSIONS

MADQUAT has antifungal activity against Candida spp. Moreover, the sensitivity to this substance varies across the different species in terms of MIC values and fungicidal or fungistatic activity.