Improved synthesis and in vitro study of antimicrobial activity of α,β-unsaturated and α-bromo carboxylic acids

Abstract

A series of α,β-unsaturated and α-bromo carboxylic acids were identified as potent antimicrobial agents. Antimicrobial activity was evaluated using broth microdilution method. All acids 1-12 exhibit a significant activity against nine laboratory control strains of bacteria and two strains of yeast Candida albicans. The tested acids were efficiently prepared by optimized phase-transfer-catalyzed (PTC) reactions of ketones with bromoform and aqueous lithium hydroxide in alcoholic solvent with TEBA as catalyst

Iodine-Catalyzed Nazarov Cyclizations

“…Cyclohex-1-ene-1-carboxylic acid was obtained following a synthesis route of Vitnik and co-workers . The required starting material ethyl 3-(cyclohex-1-en-1-yl)-3-oxopropanoate (0.94 g, 48 mmol, 40%) was obtained following the same modified procedure of Meggers and co-workers as a light yellow oil from cyclohex-1-ene-1-carboxylic acid (1.50 g, 11.9 mmol, 1.00 equiv).…”

“…15a In addition, Nazarov systems 5 containing the cyclohexene instead of a dihydropyran ring were synthesized in Knoevenagel condensation reactions between suitable aldehydes and the β-keto ester obtained from 1-cyclohexene-1-carboxylic acid. 15a,g, 19 Typically, only the most stable E-configured diastereomer was obtained. We have furthermore synthesized the indole derivatives 7 and 9 as potential starting materials with aromatic character by modifying known procedures.…”

“…Lithiation of dihydropyran, reaction with α,β-unsaturated aldehydes, and subsequent oxidation resulted in the Nazarov systems 1 , while the more polarized structures 3 were obtained from the corresponding β-keto ester and the appropriate aldehyde . In addition, Nazarov systems 5 containing the cyclohexene instead of a dihydropyran ring were synthesized in Knoevenagel condensation reactions between suitable aldehydes and the β-keto ester obtained from 1-cyclohexene-1-carboxylic acid. ,, Typically, only the most stable E -configured diastereomer was obtained. We have furthermore synthesized the indole derivatives 7 and 9 as potential starting materials with aromatic character by modifying known procedures .…”

“…30 Cyclohex-1-ene-1-carboxylic acid was obtained following a synthesis route of Vitnik and co-workers. 19 The required starting material ethyl 3-(cyclohex-1-en-1-yl)-3-oxopropanoate (0.94 g, 48 mmol, 40%) was obtained following the same modified procedure of Meggers and co-workers 15g as a light yellow oil from cyclohex-1-ene-1-carboxylic acid (1.50 g, 11.9 mmol, 1.00 equiv). Ethyl 2-(cyclohex-1-enecarbonyl)-3-(4-methoxyphenyl)acrylate (5a, 0.12 g, 0.39 mmol, 45%) was obtained from ethyl 3-(cyclohex-1-en-1-yl)-3-oxopropanoate (0.17 g, 0.88 mmol, 1.00 equiv) as a colorless oil.…”