Antibacterial activity esters

Reaction of 2-methoxytetrahydropyrrole with dioxalane-2,4-dione in presence of Et3N in benzene followed by treatment with MeONa in methanol afforded the monocyclic intermediate 185. Its treatment with BuLi followed by perfluorobenzoyl chloride gave 186 whose hydrolysis gave 187 which possess low or no antibacterial activity (96PHA805). Regiospecific intramolecular cyclization of 188 with sodium hydride yielded 189 as ester whose hydrolysis gave the respective acid (87JHC1537) (Scheme 35). 

These esters of p-hydroxybenzoic acid have been used primarily to prevent growth of molds but in higher concentrations possess some weak antibacterial activity. Their effective use is limited by low aqueous solubility and by reports of stinging and burning sensations related to their use in the eye. They bind to a number of nonionic surfactants and polymers, thereby reducing their bioactivity. They are used in combination, with the methyl ester at 0.03-0.1% and the propyl ester at 0.01-0.02%. Parabens have also been shown to promote corneal absorption [140]. 

The more recently discovered and most unusual structures include the dimeric phenazine derivatives esmeraldin A (52) and esmeraldin B (53), which are produced by Streptomyces antibioticus Tii 2706 together with 49 [54]. Esmeraldins exhibit no antibacterial activity but 53 is effective against tumor cells. Much effort has been directed to the elucidation of the biosynthesis of the esmeraldins [55]. Some rare L-quinovose esters (55a-d) of saphenic acid have... 

Shibasaki, I., and N. Kato. 1978. Combined effects on antibacterial activity of fatty acids and their esters against gram-negative bacteria. In The pharmacological effects of lipids, ed. J.J. Kabara, 15-24. St. Louis American Oil Chemists Society. 

Liu XJ, Cui P et al (2008) Synthesis, structure and antibacterial activity of novel l-(5-substituted-3-substituted-4, 5-dihydropyrazol-l-yl)ethanone oxime ester derivatives. Bioorg Med Chem 16 4075 82... 

This method can be effectively applied to the preparation of /S-lactam compounds. The ester enolate-imine condensation approach to j8-lactam formation has been developed over the past decade. Thienamycin and related carbapenems have been the focus of particular attention because of their structural uniqueness and potent antibacterial activity. 

Bacampidllln Hydrochloride. USP. Bacampicillinh -drochloride (Speetrobid) is the hydrochloride salt of the ethoxyearbonyloxycthyl ester of ampicillin. It is a prodrui of ampicillin with no antibacterial activity. After oral absorp tion. bacampicillin is hydrolyzed rapidly by esterases in iL-plasma to form ampicillin. 

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